Struts2+JQuery+JSON实现异步交互

package struts2jsonjquery.test.entity;

import java.io.Serializable;
/**
 * <p>
 *     用户实体类
 * </p>
 * @author 朱延伟
 *
 */
public class UserInfo implements Serializable {

    private static final long serialVersionUID = 3952189513312630860L;
    
    private int userId;
    private String userName;
    private String password;
    public int getUserId() {
        return userId;
    }
    public void setUserId(int userId) {
        this.userId = userId;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
}

package struts2jsonjquery.test.action;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import struts2jsonjquery.test.entity.UserInfo;

import com.opensymphony.xwork2.ActionSupport;

public class JsonJqueryStruts2Action extends ActionSupport {

    private static final long serialVersionUID = 3518833679938898354L;
    
    private String message;        //使用json返回单个值
    private UserInfo userInfo;         //使用json返回对象
    private List<UserInfo> userInfosList;        //使用josn返回List对象
    private Map<String,UserInfo> userInfosMap;     //使用json返回Map对象
    //为上面的的属性提供get，Set方法
    public String getMessage() {
        return message;
    }
    public void setMessage(String message) {
        this.message = message;
    }
    public UserInfo getUserInfo() {
        return userInfo;
    }
    public void setUserInfo(UserInfo userInfo) {
        this.userInfo = userInfo;
    }
    public List<UserInfo> getUserInfosList() {
        return userInfosList;
    }
    public void setUserInfosList(List<UserInfo> userInfosList) {
        this.userInfosList = userInfosList;
    }
    public Map<String, UserInfo> getUserInfosMap() {
        return userInfosMap;
    }
    public void setUserInfosMap(Map<String, UserInfo> userInfosMap) {
        this.userInfosMap = userInfosMap;
    }
    /**
     * <p>
     *     返回单个值
     * <p>
     * @return
     */
    public String returnMessage(){
        this.message = "成功返回单个值";
        return "message";
    }
    /**
     * <p>
     *     返回UserInfo对象
     * </p>
     * @return
     */
    public String returnUserInfo(){
        userInfo = new UserInfo();
        userInfo.setUserId(10000);
        userInfo.setUserName("张三");
        userInfo.setPassword("000000");
        return "userInfo";
    }
    /**
     * <p>
     *     返回List对象
     * </p>
     * @return
     */
    public String returnList(){
        userInfosList = new ArrayList<UserInfo>();
        UserInfo u1 = new UserInfo();
        u1.setUserId(10000);
        u1.setUserName("张三");
        u1.setPassword("000000");
        UserInfo u2 = new UserInfo();
        u2.setUserId(10001);
        u2.setUserName("李四");
        u2.setPassword("111111");
        UserInfo u3 = new UserInfo();
        u3.setUserId(10002);
        u3.setUserName("王五");
        u3.setPassword("222222");
        UserInfo u4 = new UserInfo();
        u4.setUserId(10003);
        u4.setUserName("赵六");
        u4.setPassword("333333");
        userInfosList.add(u1);
        userInfosList.add(u2);
        userInfosList.add(u3);
        userInfosList.add(u4);
        return "list";
    }
    /**
     * <p>
     *     返回Map对象
     * </p>
     * @return
     */
    public String returnMap(){
        userInfosMap = new HashMap<String,UserInfo>();
        UserInfo u1 = new UserInfo();
        u1.setUserId(10000);
        u1.setUserName("张三");
        u1.setPassword("000000");
        UserInfo u2 = new UserInfo();
        u2.setUserId(10001);
        u2.setUserName("李四");
        u2.setPassword("111111");
        UserInfo u3 = new UserInfo();
        u3.setUserId(10002);
        u3.setUserName("王五");
        u3.setPassword("222222");
        UserInfo u4 = new UserInfo();
        u4.setUserId(10003);
        u4.setUserName("赵六");
        u4.setPassword("333333");
        userInfosMap.put(u1.getUserId()+"", u1);
        userInfosMap.put(u2.getUserId()+"", u2);
        userInfosMap.put(u3.getUserId()+"", u3);
        userInfosMap.put(u4.getUserId()+"", u4);
        return "map";
    }
    /**
     * <p>
     *     获得对象，也就是通过表达获得对象(异步的)
     * </P>
     * @return
     */
    public String gainUserInfo(){
        System.out.println("用户ID："+userInfo.getUserId());
        System.out.println("用户名："+userInfo.getUserName());
        System.out.println("密码："+userInfo.getPassword());
        return "userInfo";
    }
    /**
     * 获得单个值就不用写了和平常一样
     */
}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

    <package name="default" namespace="/" extends="json-default">
        <action name="jsontest" class="struts2jsonjquery.test.action.JsonJqueryStruts2Action">
            <!-- 返回单个值的result -->
            <result name="message" type="json"></result>
            <!-- 返回UserInfo对象的 -->
            <result name="userInfo" type="json"></result>
            <!-- 返回List对象的 -->
            <result name="list" type="json"></result>
            <!-- 返回Map对象的 -->
            <result name="map" type="json"></result>
        </action>
    </package>
</struts>