Java EE – Page 2 – Alex Arriaga

alex-arriaga January 17, 2014

How to set no-cache headers in a Java EE application’s response (using a Spring controller)

Enterprise Development, Java EE No Reply

Sometimes when you do a request to a Java service you will need to add some custom headers in the response, for example, today I was creating a service to get the current logged user data and I realized one client was storing (creating a cache) the response and sometimes the service was not working as expected.

So, in my case I was using Spring MVC to create a custom XML response I wanted to add a no-cache header, for that reason I spent some time to figure out which is the right way to do it, please let me explain how you can do that easily!

1) Following is an example of a Java method that contains Spring and JAXB annotations to create a custom XML and set custom headers in the response:

	@RequestMapping(method ={RequestMethod.GET, RequestMethod.POST}, produces="application/xml")
	public @ResponseBody UserProfileResponse getUserProfileInXML(HttpServletRequest request, HttpServletResponse response) {

		// UserProfileResponse and UserProfileService are MY custom classes, but you can retrieve any class you want!
		UserProfileResponse profileResponse = new UserProfileResponse();
		UserProfileService service = UserProfileService.getInstance();	// A singleton class
		Principal principal = (Principal) request.getUserPrincipal();

		if (principal != null) {
			profileResponse.setUserProfile( service.getUserProfile(principal.getName()) );
		}

		// Setting response's headers
		response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
		response.setHeader("Pragma", "no-cache"); // HTTP 1.0.
		response.setDateHeader("Expires", 0); // Proxies.

		return profileResponse;
	}

@RequestMapping(method ={RequestMethod.GET, RequestMethod.POST}, produces="application/xml")

public @ResponseBody UserProfileResponse getUserProfileInXML(HttpServletRequest request, HttpServletResponse response) {

// UserProfileResponse and UserProfileService are MY custom classes, but you can retrieve any class you want!

UserProfileResponse profileResponse = new UserProfileResponse();

UserProfileService service = UserProfileService.getInstance(); // A singleton class

Principal principal = (Principal) request.getUserPrincipal();

if (principal != null) {

profileResponse.setUserProfile( service.getUserProfile(principal.getName()) );

}

// Setting response's headers

response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.

response.setHeader("Pragma", "no-cache"); // HTTP 1.0.

response.setDateHeader("Expires", 0); // Proxies.

return profileResponse;

}

2) The important lines in previous code are:

// Setting response's headers
response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
response.setHeader("Pragma", "no-cache"); // HTTP 1.0.
response.setDateHeader("Expires", 0); // Proxies.

// Setting response's headers

response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.

response.setHeader("Pragma", "no-cache"); // HTTP 1.0.

response.setDateHeader("Expires", 0); // Proxies.

Because they set custom response’s headers to establish a no-cache configuration.

3) Now, just to test we could do a normal request in a browser and we can see the headers:

As you can see, the headers were set correctly.

That’s it!

Be happy with your code!

alex-arriaga January 7, 2014

Setting UTF-8 encoding in a JSP (changing ISO-8859-1 to UTF-8 on IBM Rational Application Developer)

Enterprise Development, Java EE 2 Replies

Today, I was integrating a custom JSP component into IBM WCM and I noticed some characters were not displaying as expected, after looking into the generated source code in Firefox I realized the used encoding was ISO-8859-1, let me explain what ISO-8859-1 means…

According the W3C the ISO-8859-1 encoding:

ISO-8859-1 is the default character set in most browsers.

The first 128 characters of ISO-8859-1 is the original ASCII character-set (the numbers from 0-9, the uppercase and lowercase English alphabet, and some special characters).

The higher part of ISO-8859-1 (codes from 160-255) contains the characters used in Western European countries and some commonly used special characters.

Entities are used to implement reserved characters or to express characters that cannot easily be entered with the keyboard.

My source code looked like this (in Firefox):

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />

1	<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />

And this was the displayed characters (look the “Spanish”, “Portuguese” and “Russian” language labels):

Well, solution for this enconding error is really easy, we only need to:

1) Set the encoding in the JSP file (using your editor or IDE), in my case I was using Rational:

2) Type a directive to indicate we WANT to use UTF-8. At the beginning of your JSP code add following line:

<%@page language="java" contentType="text/html; charset=utf-8" %>

1	<%@page language="java" contentType="text/html; charset=utf-8" %>

That’s it! now all our messages will be ok 🙂

Be happy with your code!

alex-arriaga October 21, 2013

How to add attributes in XML elements using JAXB in dynamic web application for Java EE

Enterprise Development, Java EE No Reply

If you are trying to add an XML attribute in an XML entry using JAXB this information is for you. First of all you need to understand what an attribute in a XML entry means: in strict sense an attribute provides additional information about an element, this information could be useful to add metadata, states of an XML entry or any other extra information you want. As you know, all attribute’s values must always be quoted. Either single or double quotes can be used. Now, what’s better: use many attributes o XML elements? well, the answer according to W3C is: avoid attributes and try to adapt them to XML elements; but in my case I needed to use attributes.

1) Imagine you need to get this kind of XML output:

<profiles current="profileID1">
	<profile>
		<profile_id>profileID1</profile_id>
		<user_id>alex_arriaga</user_id>
		<name>Big Dealer Supply Co</dealer_name>
		<application>TOOL_ZH</application>
	</profile>
	<profile>
		<profile_id>profileID2</profile_id>
		<user_id>alex_arriaga_m</user_id>
		<application>TOOL_SX</application>
	</profile>
</profiles>

<profile_id>profileID1</profile_id>

<user_id>alex_arriaga</user_id>

<name>Big Dealer Supply Co</dealer_name>

</profile>

<profile_id>profileID2</profile_id>

<user_id>alex_arriaga_m</user_id>

</profile>

</profiles>

2) And you are using JAXB for dynamic generating for your XML document:

DataUserProfiles is a composed class to hold all profile data.

package com.base22.model;
import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="profiles")
@XmlAccessorType(XmlAccessType.FIELD)
public class DataUserProfiles{

	@XmlElement(name="profiles")
	private UserProfilesList profilesList;

	public DataUserProfiles(){

	}

	public DataUserProfiles(UserProfilesList profilesList){
		this.profilesList = profilesList;
	}

	public UserProfilesList getProfilesList() {
		return profilesList;
	}

	public void setProfilesList(UserProfilesList profilesList) {
		this.profilesList = profilesList;
	}

}

package com.base22.model;

import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlElementWrapper;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="profiles")

@XmlAccessorType(XmlAccessType.FIELD)

public class DataUserProfiles{

@XmlElement(name="profiles")

private UserProfilesList profilesList;

public DataUserProfiles(){

}

public DataUserProfiles(UserProfilesList profilesList){

this.profilesList = profilesList;

}

public UserProfilesList getProfilesList() {

return profilesList;

}

public void setProfilesList(UserProfilesList profilesList) {

this.profilesList = profilesList;

}

This class UserProfileList contains the definition of an attribute called current.

package com.base22.model;
import java.util.ArrayList;
import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

/**
 * This class was created to hold an attribute "current" on the list of User's profiles
 * It could be removed if another library can be added (like EclipseLink MOXy to support XmlPath annotation)
 * @author Alex Arriaga (base22.com)
 *
 */
@XmlRootElement(name="profiles")
@XmlAccessorType(XmlAccessType.FIELD)
public class UserProfilesList {
	@XmlElement(name="profile")
	private List<UserProfile> profiles;

	@XmlAttribute(name="current")
	private String currentUserProfile;

	public UserProfilesList(){
		this.profiles = new ArrayList<UserProfile>();
	}

	public UserProfilesList(List<UserProfile> listProfiles){
		this.profiles = listProfiles;
	}

	public UserProfilesList(List<UserProfile> listProfiles, String currentUserProfile){
		this.profiles = listProfiles;
		this.currentUserProfile = currentUserProfile;
	}

	public List<UserProfile> getProfiles() {
		return profiles;
	}

	public void setProfiles(List<UserProfile> profiles) {
		this.profiles = profiles;
	}

	public String getCurrentUserProfile() {
		return currentUserProfile;
	}

	public void setCurrentUserProfile(String currentUserProfile) {
		this.currentUserProfile = currentUserProfile;
	}

}

package com.base22.model;

import java.util.ArrayList;

import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlAttribute;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlRootElement;

/**

* This class was created to hold an attribute "current" on the list of User's profiles

* It could be removed if another library can be added (like EclipseLink MOXy to support XmlPath annotation)

* @author Alex Arriaga (base22.com)

@XmlRootElement(name="profiles")

@XmlAccessorType(XmlAccessType.FIELD)

public class UserProfilesList {

@XmlElement(name="profile")

private List<UserProfile> profiles;

@XmlAttribute(name="current")

private String currentUserProfile;

public UserProfilesList(){

this.profiles = new ArrayList<UserProfile>();

}

public UserProfilesList(List<UserProfile> listProfiles){

this.profiles = listProfiles;

}

public UserProfilesList(List<UserProfile> listProfiles, String currentUserProfile){

this.profiles = listProfiles;

this.currentUserProfile = currentUserProfile;

}

public List<UserProfile> getProfiles() {

return profiles;

}

public void setProfiles(List<UserProfile> profiles) {

this.profiles = profiles;

}

public String getCurrentUserProfile() {

return currentUserProfile;

}

public void setCurrentUserProfile(String currentUserProfile) {

this.currentUserProfile = currentUserProfile;

}

Finally, class UserProfile contains: userId, profileId, name and application elements.

package com.base22.model;

import java.util.ArrayList;
import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;

/**
 * @author Alex Arriaga
 *
 */
@XmlRootElement(name = "profile")
@XmlAccessorType(XmlAccessType.FIELD)
public class UserProfile{
	@XmlElement(name="profile_id")
	private String profileId;

	@XmlElement(name="user_id")
	private String userId;

	@XmlElement(name="name")
	private String name;

	@XmlElement(name="application")
	private String application;

	public UserProfile(){

	}

	public UserProfile(String userId, String name, String application){
		this.userId = userId;
		this.profileId = "profile" + this.userId;
		this.name = name;
		this.application = application;
	}

	public String getProfileId() {
		return profileId;
	}

	public void setProfileId(String profileId) {
		this.profileId = profileId;
	}

	public String getUserId() {
		return userId;
	}

	public void setUserId(String userId) {
		this.userId = userId;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = dealerName;
	}

	public String getApplication() {
		return application;
	}

	public void setApplication(String application) {
		this.application = application;
	}
}

package com.base22.model;

import java.util.ArrayList;

import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlElementWrapper;

import javax.xml.bind.annotation.XmlRootElement;

/**

* @author Alex Arriaga

@XmlRootElement(name = "profile")

@XmlAccessorType(XmlAccessType.FIELD)

public class UserProfile{

@XmlElement(name="profile_id")

private String profileId;

@XmlElement(name="user_id")

private String userId;

@XmlElement(name="name")

private String name;

@XmlElement(name="application")

private String application;

public UserProfile(){

}

public UserProfile(String userId, String name, String application){

this.userId = userId;

this.profileId = "profile" + this.userId;

this.name = name;

this.application = application;

}

public String getProfileId() {

return profileId;

}

public void setProfileId(String profileId) {

this.profileId = profileId;

}

public String getUserId() {

return userId;

}

public void setUserId(String userId) {

this.userId = userId;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = dealerName;

}

public String getApplication() {

return application;

}

public void setApplication(String application) {

this.application = application;

}

3) As you can see, it’s very easy to add an XML attribute to your Java class, just type the annotation “@XmlAttribute” and JAXB will create your attribute automatically.

@XmlAttribute(name="current")
private String currentUserProfile;

1 2	@XmlAttribute(name="current") private String currentUserProfile;

That’s it!

Be happy with your code!

alex-arriaga October 16, 2013

“IWKMU1026X: File not found” error when render WCM components or elements in IBM WCM 6 SOLVED

Enterprise Development, IBM Web Content Manager, IBM WebSphere, Java EE 1 Reply

Today, I spent a lot of time trying to render an ImageComponent using the WCM 6 API, because when I used the method render() from the workspace this error was appearing:

IWKMU1026X: File not found

The thing is, almost all in the web point to a permission issue, but at the end my solution is not necessarily related with that kind of issues. Please, pay attention in next steps in order to solve this error correctly.

1) Of course, the first thing that we need to be sure is that we have permission for reading information from WCM using the API. So, how can we verify that?

Use next way if you have possibility to enable WebSphere logs (if not, just replace LOG.log() by System.out.println()):

// This obtains an HTML Component called "Rendering-An-HTML-Component" to render it later (you can use any other component to test this)
DocumentIdIterator componentIdIterator = workspace.findComponentByName("Rendering-An-HTML-Component");

while(componentIdIterator.hasNext())
{
	DocumentId cmpntId = (DocumentId)componentIdIterator.next();
	LibraryHTMLComponent htmlComponent = (LibraryHTMLComponent) workspace.getById(cmpntId);

	if(LOG.isLoggable(WsLevel.DETAIL)){
		// Here, we verify if we have access to our HTML component
		LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasUserAccess: "+ workspace.hasUserAccess(cmpntId));
		LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasContributorAccess: "+ workspace.hasContributorAccess(cmpntId));
		LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasEditorAccess: "+ workspace.hasEditorAccess(cmpntId));
		LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasManagerAccess: "+ workspace.hasManagerAccess(cmpntId));

		// Also, we can get the current user profile
		UserProfile userProfile = workspace.getUserProfile();
		if(userProfile != null){
			LOG.log(WsLevel.DETAIL, "-- addImageComponent(): getUsername(): "+ userProfile.getUsername());
		}else{
			LOG.log(WsLevel.DETAIL, "-- addImageComponent(): UserProfile is NULL.");
		}
	}
}

// This obtains an HTML Component called "Rendering-An-HTML-Component" to render it later (you can use any other component to test this)

DocumentIdIterator componentIdIterator = workspace.findComponentByName("Rendering-An-HTML-Component");

while(componentIdIterator.hasNext())

{

DocumentId cmpntId = (DocumentId)componentIdIterator.next();

LibraryHTMLComponent htmlComponent = (LibraryHTMLComponent) workspace.getById(cmpntId);

if(LOG.isLoggable(WsLevel.DETAIL)){

// Here, we verify if we have access to our HTML component

LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasUserAccess: "+ workspace.hasUserAccess(cmpntId));

LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasContributorAccess: "+ workspace.hasContributorAccess(cmpntId));

LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasEditorAccess: "+ workspace.hasEditorAccess(cmpntId));

LOG.log(WsLevel.DETAIL, "-- addImageComponent(): hasManagerAccess: "+ workspace.hasManagerAccess(cmpntId));

// Also, we can get the current user profile

UserProfile userProfile = workspace.getUserProfile();

if(userProfile != null){

LOG.log(WsLevel.DETAIL, "-- addImageComponent(): getUsername(): "+ userProfile.getUsername());

}else{

LOG.log(WsLevel.DETAIL, "-- addImageComponent(): UserProfile is NULL.");

}

A possible output could be something like this:

-- addImageComponent(): hasUserAccess: true
-- addImageComponent(): hasContributorAccess: true
-- addImageComponent(): hasEditorAccess: true
-- addImageComponent(): hasManagerAccess: true
-- addImageComponent(): getUsername(): wps admin

-- addImageComponent(): hasUserAccess: true

-- addImageComponent(): hasContributorAccess: true

-- addImageComponent(): hasEditorAccess: true

-- addImageComponent(): hasManagerAccess: true

-- addImageComponent(): getUsername(): wps admin

2) The RenderingContext object must be well configured, in my case the path of the content was not well constructed. If you don’t know anything about Rendering Context, maybe this article will be useful: https://wiki.base22.com/display/btg/Understand+rendering+contexts.

So, the configuration that I used was this:

// content is an instance of com.ibm.workplace.wcm.api.Content
String pathContent = workspace.getPathById(content.getId(), true, true);
renderingContext.setRenderedContent(pathContent);

// content is an instance of com.ibm.workplace.wcm.api.Content

String pathContent = workspace.getPathById(content.getId(), true, true);

renderingContext.setRenderedContent(pathContent);

Method setRenderedContent() is very important because it is used in order to render all Image Components that “live” in the CURRENT piece of content or external components.

3) In my case I needed to render an image loaded as element in a piece of content, so, for rendering that image, following code was necessary:

ImageComponent image = (ImageComponent) content.getComponentByReference("myImageElementInPieceOfContent");
String renderedImage = workspace.render(renderingContext,image);

1 2	ImageComponent image = (ImageComponent) content.getComponentByReference("myImageElementInPieceOfContent"); String renderedImage = workspace.render(renderingContext,image);

4) After executing the render() method, we will get a String with the full-image-tag, for example:

<img src="/wcm/myconnect/f5ec6f004174a7c1a3f4a37ca91860da/std_tr270_wide_cover.jpg?MOD=AJPERES&amp;CACHEID=f5ec6f004174a7c1a3f4a37ca91860da" border="0" width="1024" height="330" />

1	<img src="/wcm/myconnect/f5ec6f004174a7c1a3f4a37ca91860da/std_tr270_wide_cover.jpg?MOD=AJPERES&CACHEID=f5ec6f004174a7c1a3f4a37ca91860da" border="0" width="1024" height="330" />

If we want just the image URL, we can create a regular expression to get it. Next code, will obtain a String like: /wcm/myconnect/1d433c004174a7c2a3f8a37ca91860da/std_tr270_small_product_preview.jpg?MOD=AJPERES please don’t remove ?MOD=AJPERES that is required by WCM to render our image given the URL.

Pattern pattern = Pattern.compile("(<img\\s*src=\\s*\")(.*?)(\\&)");
Matcher m = pattern.matcher(renderedImage);
while(m.find()){
	imageURL = m.group(2); // Gets the URL
}

Pattern pattern = Pattern.compile("(<img\\s*src=\\s*\")(.*?)(\\&)");

Matcher m = pattern.matcher(renderedImage);

while(m.find()){

imageURL = m.group(2); // Gets the URL

}

5) Be sure your piece of content is PUBLISHED!

6) If after following previous steps, you are getting the same error maybe you forgot the same as me: MAPPINGS between Authoring Templates and Presentation Templates in the site areas that contain the contents that you are using for configuring your Rendering Context object.

So, please go to WCM then look for your site area and check you have mappings well configured (see next image as an example).

That’s it!

Be happy with your code!

alex-arriaga September 26, 2013

Solving “The matching wildcard is strict, but no declaration can be found for element mvc:annotation-driven”

Enterprise Development, IBM WebSphere, Java EE No Reply

If you are using Spring to create an awesome enterprise application and you are a beginner like me this article is for you. Today when I was integrating new configurations to Spring MVC to an existing project an error appeared, this error was related with <mvc-anotation-driven /> annotation. At the beginning I thought it would be easy to solve it, but not at all… so this is proof that in Enterprise Web Development, every single character in code is really important. The error was appearing is the next (also, see the image):

Description Resource Path Location Type
cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element 'mvc:annotation-driven'. dispatcher-servlet.xml dealerweb/WebContent/WEB-INF line 28 XML Problem

cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element 'mvc:resources'. dispatcher-servlet.xml dealerweb/WebContent/WEB-INF line 27 XML Problem

Description Resource Path Location Type

cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element 'mvc:annotation-driven'. dispatcher-servlet.xml dealerweb/WebContent/WEB-INF line 28 XML Problem

cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element 'mvc:resources'. dispatcher-servlet.xml dealerweb/WebContent/WEB-INF line 27 XML Problem

The file with the problem (dispatcher-servlet.xml)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:p="http://www.springframework.org/schema/p"  
	xmlns:context="http://www.springframework.org/schema/context" 
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.0.xsd 
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">

	<context:property-placeholder location="classpath:/config.properties"/>

	<!-- Spring will search in the bellow paths controller an services annotations-->	
	<context:component-scan base-package="com.rest.web" /> 
 	<mvc:resources mapping="/css/**" location="/css/" />
	<mvc:annotation-driven />

	<!-- More code goes here -->
</beans>

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:p="http://www.springframework.org/schema/p"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:mvc="http://www.springframework.org/schema/mvc"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.0.xsd

http://www.springframework.org/schema/mvc

http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">

<context:property-placeholder location="classpath:/config.properties"/>

<context:component-scan base-package="com.rest.web" />

<mvc:resources mapping="/css/**" location="/css/" />

<mvc:annotation-driven />

</beans>

Solution

After spending more than three hours to try to fix this compile error, the only wrong thing that I had was:

1) Version of XML schemes:

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

1	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

http://www.springframework.org/schema/context/spring-context-3.0.xsd

1	http://www.springframework.org/schema/context/spring-context-3.0.xsd

They should be compatible with:

http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd

1	http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd

2) Be sure, what Spring version you are using. In my case my .jar files are Spring 3.1 which is different to Spring 3.0 (this is very important).

3) Of course, you should check if you have Spring MVC jar file loaded in your project libraries.

So, the fixed file is this:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:p="http://www.springframework.org/schema/p"  
	xmlns:context="http://www.springframework.org/schema/context" 
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.1.xsd 
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">

	<context:property-placeholder location="classpath:/config.properties"/>

	<!-- Spring will search in the bellow paths controller an services annotations-->	
	<context:component-scan base-package="com.rest.web" /> 
 	<mvc:resources mapping="/css/**" location="/css/" />
	<mvc:annotation-driven />

	<!-- More code goes here -->
</beans>

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:p="http://www.springframework.org/schema/p"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:mvc="http://www.springframework.org/schema/mvc"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.1.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.1.xsd

http://www.springframework.org/schema/mvc

http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">

<context:property-placeholder location="classpath:/config.properties"/>

<context:component-scan base-package="com.rest.web" />

<mvc:resources mapping="/css/**" location="/css/" />

<mvc:annotation-driven />

</beans>

What does “<mvc-annotation-driven />” do?

Taken from the official documentation: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/mvc.html

“The above registers a RequestMappingHandlerMapping, a RequestMappingHandlerAdapter, and an ExceptionHandlerExceptionResolver (among others) in support of processing requests with annotated controller methods using annotations such as @RequestMapping , @ExceptionHandler, and others”.

It also enables the following:

Spring 3 style type conversion through a ConversionService instance in addition to the JavaBeans PropertyEditors used for Data Binding.
Support for formatting Number fields using the @NumberFormat annotation through the ConversionService.
Support for formatting Date, Calendar, Long, and Joda Time fields using the @DateTimeFormat annotation.
Support for validating @Controller inputs with @Valid, if a JSR-303 Provider is present on the classpath.
HttpMessageConverter support for @RequestBody method parameters and @ResponseBody method return values from @RequestMapping or @ExceptionHandler methods.
This is the complete list of HttpMessageConverters set up by mvc:annotation-driven:
ByteArrayHttpMessageConverter converts byte arrays.
StringHttpMessageConverter converts strings.
ResourceHttpMessageConverter converts to/from org.springframework.core.io.Resource for all media types.
SourceHttpMessageConverter converts to/from a javax.xml.transform.Source.
FormHttpMessageConverter converts form data to/from a MultiValueMap<String, String>.
Jaxb2RootElementHttpMessageConverter converts Java objects to/from XML — added if JAXB2 is present on the classpath.
MappingJackson2HttpMessageConverter (or MappingJacksonHttpMessageConverter) converts to/from JSON — added if Jackson 2 (or Jackson) is present on the classpath.
AtomFeedHttpMessageConverter converts Atom feeds — added if Rome is present on the classpath.
RssChannelHttpMessageConverter converts RSS feeds — added if Rome is present on the classpath.

That’s it!

Be happy with your code!

alex-arriaga September 25, 2013

How to solve the “Class has two properties of the same name” JAXB error (WebSphere Application Server)

Enterprise Development, IBM WebSphere, Java EE No Reply

Today, when I was creating a RESTful service in JavaEE for a dynamic web application to run in IBM® WebSphere Application Server (WAS) an error like this was appearing:

Class has two properties of the same name "userId" 
this problem is related to the following location: 
at public java.lang.String com.rest.model.UserProfile.getUserId() 
at com.rest.model.UserProfile this problem is related to the following location: 
at private java.lang.String com.rest.model.UserProfile.userId 
at com.rest.model.UserProfile

Class has two properties of the same name "userId"

this problem is related to the following location:

at public java.lang.String com.rest.model.UserProfile.getUserId()

at com.rest.model.UserProfile this problem is related to the following location:

at private java.lang.String com.rest.model.UserProfile.userId

at com.rest.model.UserProfile

After looking for documentation and all related issues, I found a solution that I would like to share with you:

1) My class looked like this:

package com.rest.model;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlType;

/**
 * @author Alex Arriaga
 */
@XmlRootElement(name = "profile")
public class UserProfile{
	@XmlElement(name="user_id")
	private String userId;

	// More code here...

	public UserProfile(){

	}

	public UserProfile(String s){
		this.test = s;
	}

	public String getUserId() {
		return userId;
	}

	public void setUserId(String userId) {
		this.userId = userId;
	}

	// More code here...

}

package com.rest.model;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlRootElement;

import javax.xml.bind.annotation.XmlElementWrapper;

import javax.xml.bind.annotation.XmlType;

/**

* @author Alex Arriaga

@XmlRootElement(name = "profile")

public class UserProfile{

@XmlElement(name="user_id")

private String userId;

// More code here...

public UserProfile(){

}

public UserProfile(String s){

this.test = s;

}

public String getUserId() {

return userId;

}

public void setUserId(String userId) {

this.userId = userId;

}

// More code here...

}

2) How to fix it

It was really easy after spending time to search this issue. My JAXB was looking at both the getUserId() method and the member userId. I didn’t say which JAXB implementation I was using, the exception was fairly clear but that was the first time that I was working with JABX, at the beginning it is a little complicated to understand that message.

To solve this issue just was necessary to specify to JAXB which implementation I wanted to use using @XmlAccessorType(XmlAccessType.FIELD) annotation after @XmlRootElement(name = “profile”) please, see next code to have a clearer idea.

package com.rest.model;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlType;

/**
 * @author Alex Arriaga
 *
 */
@XmlRootElement(name = "profile")
@XmlAccessorType(XmlAccessType.FIELD) // This line was added
public class UserProfile{
	@XmlElement(name="user_id")
	private String userId;

	// More code here...

	public UserProfile(){

	}

	public UserProfile(String s){
		this.test = s;
	}

	public String getUserId() {
		return userId;
	}

	public void setUserId(String userId) {
		this.userId = userId;
	}

	// More code here...

}

package com.rest.model;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlRootElement;

import javax.xml.bind.annotation.XmlElementWrapper;

import javax.xml.bind.annotation.XmlType;

/**

* @author Alex Arriaga

@XmlRootElement(name = "profile")

@XmlAccessorType(XmlAccessType.FIELD) // This line was added

public class UserProfile{

@XmlElement(name="user_id")

private String userId;

// More code here...

public UserProfile(){

}

public UserProfile(String s){

this.test = s;

}

public String getUserId() {

return userId;

}

public void setUserId(String userId) {

this.userId = userId;

}

// More code here...

}

That’s it!

Be happy with your code.

alex-arriaga July 16, 2013

How to use and understand Binary Search on Java SE

Enterprise Development, Java EE 2 Replies

Java is a Platform to create robust, secure and scalable stand-alone and enterprise web applications. It has a lot of classes and resources that make easy to develop many functionalities in systems. One of the most interesting parts of the Java API (Application Programming interface) is work with collections and generics. Basically, Java has three kinds of “collections”: Set, List and Map (this one is not necessarily a collection but it is enough alike than one, so its use doesn’t cause any problem, if we understand how collections work).

Well, in Java there is a special static class called Arrays (java.util.Arrays),

This class contains various methods for manipulating arrays (such as sorting and searching). This class also contains a static factory that allows arrays to be viewed as lists.

Today, I would like to show you how to use a method that implements Binary Search, but before we could check the official information about this method:

Binary Search method. Searches the specified array of ints for the specified value using the binary search algorithm. The array must be sorted (as by the sort(int[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found.

This method has a lot of overrides, for more information about them, please visit: http://docs.oracle.com/javase/6/docs/api/java/util/Arrays.html#binarySearch(java.lang.Object[], java.lang.Object)

Now, imagine that we have the next code:

import java.util.*;

public class ArraysTest{
	public static void main(String [] args) {
		String [] colors = {"blue", "red", "green", "yellow", "orange"};

		// It is necessary to have an ordered array
		Arrays.sort(colors);
		for(String color : colors)
			System.out.print(color + " ");

		int index1 = Arrays.binarySearch(colors, "orange");
		int index2 = Arrays.binarySearch(colors, "violet");
		System.out.println("\norange => " + index1);
		System.out.println("violet => " + index2);
	}
}

import java.util.*;

public class ArraysTest{

public static void main(String [] args) {

String [] colors = {"blue", "red", "green", "yellow", "orange"};

// It is necessary to have an ordered array

Arrays.sort(colors);

for(String color : colors)

System.out.print(color + " ");

int index1 = Arrays.binarySearch(colors, "orange");

int index2 = Arrays.binarySearch(colors, "violet");

System.out.println("\norange => " + index1);

System.out.println("violet => " + index2);

}

The output is something like this:

blue green orange red yellow
orange => 2
violet => -5

blue green orange red yellow

orange => 2

violet => -5

According to the API:

Parameters:
- a – the array to be searched
- key – the value to be searched for
Returns:
- index of the search key, if it is contained in the array; otherwise, (-(insertion point) – 1). The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or a.length if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws:
- ClassCastException – if the search key is not comparable to the elements of the array.

Explanation

The first result after searching for “orange” is clear because “orange” was found in the index: 2.

Second result is a little more complex. Let me ask you, was “violet” found in the array? what should the index where “violet” be inserted? Well, see next image to understand better:

As you can see index:4 is where “violet” should be inserted. For this reason binarySearch return -5 (see next operation for more details):

-(insertion point) - 1 = -(4) -1 = -5

1	-(insertion point) - 1 = -(4) -1 = -5

That’s it, at this moment.

Be happy with your code!

—

Alex Arriaga

What would you like to know about?

Alex Arriaga

Category Archives:
Java EE

How to set no-cache headers in a Java EE application’s response (using a Spring controller)

Setting UTF-8 encoding in a JSP (changing ISO-8859-1 to UTF-8 on IBM Rational Application Developer)

How to add attributes in XML elements using JAXB in dynamic web application for Java EE

“IWKMU1026X: File not found” error when render WCM components or elements in IBM WCM 6 SOLVED

Solving “The matching wildcard is strict, but no declaration can be found for element mvc:annotation-driven”

The file with the problem (dispatcher-servlet.xml)

Solution

What does “<mvc-annotation-driven />” do?

How to solve the “Class has two properties of the same name” JAXB error (WebSphere Application Server)

1) My class looked like this:

2) How to fix it

How to use and understand Binary Search on Java SE

Join me, have fun and learn!

Recent Posts

Recent Comments

Join me, have fun and learn!

Recent Posts

Day quote…

Recent Comments

Categories

Archives

Join me, have fun and learn!

Recent Posts

Archives

Recent Comments

Categories

What would you like to know about?

Category Archives:Java EE

The file with the problem (dispatcher-servlet.xml)

Solution

What does “<mvc-annotation-driven />” do?

1) My class looked like this:

2) How to fix it

Join me, have fun and learn!

Tag Cloud

Recent Posts

Recent Comments

Join me, have fun and learn!

Recent Posts

Day quote…

Recent Comments

Categories

Tag Cloud

Archives

Join me, have fun and learn!

Recent Posts

Archives

Tag Cloud

Recent Comments

Categories

Category Archives:
Java EE