Struts2返回JSON对象的方法总结

             1
            public
            void write() throws IOException{
 2     HttpServletResponse response=ServletActionContext.getResponse();
 3/* 4     * 在调用getWriter之前未设置编码(既调用setContentType或者setCharacterEncoding方法设置编码),
 5     * HttpServletResponse则会返回一个用默认的编码(既ISO-8859-1)编码的PrintWriter实例。这样就会
 6     * 造成中文乱码。而且设置编码时必须在调用getWriter之前设置,不然是无效的。
 7     * */ 8     response.setContentType("text/html;charset=utf-8");
 9//response.setCharacterEncoding("UTF-8");10     PrintWriter out = response.getWriter();
11//JSON在传递过程中是普通字符串形式传递的，这里简单拼接一个做测试12     String jsonString="{\"user\":{\"id\":\"123\",\"name\":\"张三\",\"say\":\"Hello , i am a action to print a json!\",\"password\":\"JSON\"},\"success\":true}";
13    out.println(jsonString);
14    out.flush();
15    out.close();
16 }

            1 <action name="write" class="json.JsonAction" method="write" />  

            1 {"user":{"id":"123","name":"张三","say":"Hello , i am a action to print a json!","password":"JSON"},"success":true}   

             1
            package
             json;

             2
             3
            import
             java.util.HashMap;

             4
            import
             java.util.Map;

             5
             6
            import
             org.apache.struts2.json.annotations.JSON;

             7
            import
             com.opensymphony.xwork2.ActionSupport;

             8
             9
            /**
            10
             * JSON测试

            11
             * 

            12
             * 
            @author
             Watson Xu

            13
             * @date 2012-8-4 下午06:21:01

            14
            */
            15
            public
            class JsonAction extends ActionSupport{
16privatestaticfinallong serialVersionUID = 1L;
1718private Map<String,Object> dataMap;
19private String key = "Just see see";
2021public String json() {
22// dataMap中的数据将会被Struts2转换成JSON字符串，所以这里要先清空其中的数据23         dataMap = new HashMap<String, Object>();
24         User user = new User();
25         user.setName("张三");
26         user.setPassword("123");
27         dataMap.put("user", user);
28// 放入一个是否操作成功的标识29         dataMap.put("success", true);
30// 返回结果31return SUCCESS;
32    }
3334public Map<String, Object> getDataMap() {
35return dataMap;
36    }
3738//设置key属性不作为json的内容返回39     @JSON(serialize=false)
40public String getKey() {
41return key;
42    }
4344 }

             1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 4     "http://struts.apache.org/dtds/struts-2.0.dtd">
 5 <struts> 
 6      <package name="json" extends="struts-default,json-default" >
 7         <action name="json" class="json.JsonAction" method="json">
 8             <result type="json">
 9                 <!-- 这里指定将被Struts2序列化的属性，该属性在action中必须有对应的getter方法 -->
10                 <param name="root">dataMap</param>
11             </result>
12         </action>
13     </package>
14 </struts>

            1 {"success":true,"user":{"name":"张三","password":"123"}}  

             1 <dependencies>
 2     <!-- struts2核心依赖 -->
 3     <dependency>
 4         <groupId>org.apache.struts</groupId>
 5         <artifactId>struts2-core</artifactId>
 6         <version>2.3.4</version>
 7         <type>jar</type>
 8         <scope>compile</scope>
 9     </dependency>
10     <!-- struts2零配置依赖 -->
11     <dependency>
12         <groupId>org.apache.struts</groupId>
13         <artifactId>struts2-convention-plugin</artifactId>
14         <version>2.3.4</version>
15         <type>jar</type>
16         <scope>compile</scope>
17     </dependency>
18     <!-- struts2的json依赖 -->
19     <dependency>
20         <groupId>org.apache.struts</groupId>
21         <artifactId>struts2-json-plugin</artifactId>
22         <version>2.3.4</version>
23         <type>jar</type>
24         <scope>compile</scope>
25     </dependency>
26 </dependencies>

             1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
 3     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
 5     http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 6 7     <filter> 
 8         <filter-name>StrutsPrepareAndExecuteFilter </filter-name> 
 9         <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter </filter-class>
10         <init-param>
11             <param-name>config</param-name>
12             <param-value>struts-default.xml,struts-plugin.xml,struts.xml</param-value>
13         </init-param> 
14     </filter>
15     <filter-mapping>
16         <filter-name>StrutsPrepareAndExecuteFilter</filter-name>
17         <url-pattern>/*</url-pattern>
18    </filter-mapping>
19</web-app>

             1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE struts PUBLIC
 3 "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
 4 "http://struts.apache.org/dtds/struts-2.0.dtd">
 5 6 <struts>
 7     <package name="base" extends="json-default,struts-default">
 8         <!-- 这里可以设置一些全局的返回值映射关系等 -->
 9     </package>
1011     <constant name="struts.action.extension" value="" />
12     <constant name="struts.ui.theme" value="simple" />
13     <constant name="struts.i18n.encoding" value="utf-8" />
14     <constant name="struts.multipart.maxSize" value="1073741824"/>
15     <constant name="struts.devMode" value="false"/>
16 </struts>

             1
            package
             watson.action;

             2
             3
            import
             java.util.HashMap;

             4
            import
             java.util.Map;

             5
             6
            import
             org.apache.struts2.convention.annotation.Action;

             7
            import
             org.apache.struts2.convention.annotation.Namespace;

             8
            import
             org.apache.struts2.convention.annotation.ParentPackage;

             9
            import
             org.apache.struts2.convention.annotation.Result;

            10
            import
             org.apache.struts2.convention.annotation.Results;

            11
            12 @ParentPackage("base")
13 @Namespace("/watson")
14@Results({
15     @Result(name = "json",type="json", params={"root","msg"})
16})
17publicclass JsonAction {
1819     @Action(value="json")
20public String json() {
21         msg = new HashMap<String, Object>();
22         msg.put("flag", "success");
2324         Map<String, String> user = new HashMap<String, String>();
25         user.put("name", "张三");
26         user.put("age", "34");
27         msg.put("user", user);
28return "json";
29    }
3031//==================================32private Map<String, Object> msg;
3334public Map<String, Object> getMsg() {
35return msg;
36    }
3738 }

            1 {"flag":"success","user":{"age":"34","name":"张三"}}  

            1 @ParentPackage("base")
2 @Namespace("/watson")
3@Results({
4     @Result(name = "json",type="json", params={"root","msg"})
5 })

             1 <result type="json">
 2     <!-- 这里指定将被Struts2序列化的属性，该属性在action中必须有对应的getter方法 -->
 3     <!-- 默认将会序列所有有返回值的getter方法的值，而无论该方法是否有对应属性 -->
 4     <param name="root">dataMap</param>
 5     <!-- 指定是否序列化空的属性 -->
 6     <param name="excludeNullProperties">true</param>
 7     <!-- 这里指定将序列化dataMap中的那些属性 -->
 8     <param name="includeProperties">userList.*</param>
 9     <!-- 这里指定将要从dataMap中排除那些属性，这些排除的属性将不被序列化，一般不与上边的参数配置同时出现 -->
10     <param name="excludeProperties">SUCCESS</param>
11 </result>