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struts2：JSON在struts中的应用（JSP页面中将对象转换为JSON字符串提交、JSP页面中获取后台Response返回的JSON对象）

JSON主要创建如下两种数据对象：

由JSON格式字符串创建，转换成JavaScript的Object对象；
由JSON格式字符串创建，转换成JavaScript的List或数组链表对象。

更多关于JSON的信息，请参考：JSON概述及其在JavaScript与Java中的应用（整理）

1. JSP页面中将对象转换为JSON字符串提交

1.1 创建JSP文件（convertObject2Json.jsp）

<%@ page language="java" import="java.util.*" pageEncoding="utf-8" %>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <script type="text/javascript" src="../../js/json2.js">
        </script>
        <script type="text/javascript">
            function ajaxTransferText(){
                var BigText = document.getElementById("BigText").value;
                var ajaxTransferObjectRef = new ajaxTransferObject("张三", "密码11", 10, BigText);
                var JSONString = JSON.stringify(ajaxTransferObjectRef);
                
                if (window.ActiveXObject) {
                    myAjaxObject = new ActiveXObject("Microsoft.XMLHTTP");
                }
                else {
                    myAjaxObject = new XMLHttpRequest();
                }
                
                var urlString = "jsonString=" + JSONString;
                
                alert(urlString);
                myAjaxObject.open("POST", "postJson.action"+"?timestamp=" + new Date().getTime(), true);
                myAjaxObject.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
                
                myAjaxObject.send(urlString);
            }
            
            function ajaxTransferObject(username, password, age, BigText){
                this.username = username;
                this.password = password;
                this.age = age;
                this.BigText = BigText;
            }
        </script>
    </head>
    <body>
        <textarea name="textarea" id="BigText" cols="45" rows="5">需要提交的信息主体...</textarea>
        <br/>
        <input type="button" value="提交试试" onclick="ajaxTransferText()"/>
    </body>
</html>

1.2 创建后台处理Action类

package com.clzhang.ssh.demo6;

import net.sf.json.JSONObject;

import com.opensymphony.xwork2.ActionSupport;

/**
 * 获取前台提交的JSON数据
 * @author Administrator
 *
 */
public class PostJSONAction extends ActionSupport {
    public static final long serialVersionUID = 1;

    private String jsonString;

    public String getJsonString() {
        return jsonString;
    }

    public void setJsonString(String jsonString) {
        this.jsonString = jsonString;
    }

    public String execute() {
        System.out.println(jsonString);
        
        JSONObject json = JSONObject.fromObject(jsonString);
        System.out.println("username=" + json.get("username"));
        System.out.println("username=" + json.get("password"));
        System.out.println("username=" + json.get("age"));
        System.out.println("username=" + json.get("BigText"));

        return null;
    }
}

1.3 修改配置文件struts.xml

        <action name="postJson" class="com.clzhang.ssh.demo6.PostJSONAction">
        </action>

1.4 测试

打开IE，输入地址：http://127.0.0.1:8080/st/ssh/demo6/convertObject2Json.jsp

结果如下：

确定后，后台显示：

2. JSP页面获取后台Response返回的JSON对象

2.1 创建JSP文件（getJsonFromResp.jsp）

<%@ page language="java" import="java.util.*" pageEncoding="utf-8" %>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <script type="text/javascript" src="../../js/json2.js">
        </script>
        <script type="text/javascript">
            var myAjaxObject;
            //在List中存字符串
            function getListString(){
                if (window.ActiveXObject) {
                    myAjaxObject = new ActiveXObject("Microsoft.XMLHTTP");
                }
                else {
                    myAjaxObject = new XMLHttpRequest();
                }
                
                myAjaxObject.open("GET", "getJson!listString.action?date=" + new Date().getTime(), true);
                myAjaxObject.onreadystatechange = retrunListString;
                myAjaxObject.send();
            }
            
            function retrunListString(){
                if (myAjaxObject.readyState == 4) {
                    if (myAjaxObject.status == 200) {
                        var returnJSONString = myAjaxObject.responseText;
                        var returnJSON = JSON.parse(returnJSONString);
                        var showString = "";
                        for (var i = 0; i < returnJSON.length; i++) {
                            showString = showString + returnJSON[i] + " ";
                        }
                        alert(showString);
                    }
                }
            }
            
            //在List中存Bean            
            function getListBean(){
                if (window.ActiveXObject) {
                    myAjaxObject = new ActiveXObject("Microsoft.XMLHTTP");
                }
                else {
                    myAjaxObject = new XMLHttpRequest();
                }
                
                myAjaxObject.open("GET", "getJson!listBean.action?date=" + new Date().getTime(), true);
                myAjaxObject.onreadystatechange = retrunListBean;
                myAjaxObject.send();
            }
            
            function retrunListBean(){
                if (myAjaxObject.readyState == 4) {
                    if (myAjaxObject.status == 200) {
                        var returnJSONString = myAjaxObject.responseText;
                        var returnJSON = JSON.parse(returnJSONString);
                        var showString = "";
                        for (var i = 0; i < returnJSON.length; i++) {
                            showString = showString + returnJSON[i].username + " " + returnJSON[i].password + " " + returnJSON[i].age + " " + returnJSON[i].createDate + "
";
                        }
                        alert(showString);
                    }
                }
            }
            
            //在Map中存字符串            
            function getMapString(){
                if (window.ActiveXObject) {
                    myAjaxObject = new ActiveXObject("Microsoft.XMLHTTP");
                }
                else {
                    myAjaxObject = new XMLHttpRequest();
                }
                
                myAjaxObject.open("GET", "getJson!mapString.action?date=" + new Date().getTime(), true);
                myAjaxObject.onreadystatechange = retrunMapString;
                myAjaxObject.send();
            }
            
            function retrunMapString(){
                if (myAjaxObject.readyState == 4) {
                    if (myAjaxObject.status == 200) {
                        var returnJSONString = myAjaxObject.responseText;
                        var returnJSON = JSON.parse(returnJSONString);
                        var showString = "";
                        for (var i in returnJSON[0]) {
                            showString = showString + "key=" + i + " value=" + returnJSON[0][i] + "
";
                        }
                        alert(showString);
                    }
                }
            }
            
            //在Map中存Bean            
            function getMapBean(){
                if (window.ActiveXObject) {
                    myAjaxObject = new ActiveXObject("Microsoft.XMLHTTP");
                }
                else {
                    myAjaxObject = new XMLHttpRequest();
                }
                
                myAjaxObject.open("GET", "getJson!mapBean.action?date=" + new Date().getTime(), true);
                myAjaxObject.onreadystatechange = retrunMapBean;
                myAjaxObject.send();
            }
            
            function retrunMapBean(){
                if (myAjaxObject.readyState == 4) {
                    if (myAjaxObject.status == 200) {
                        var returnJSONString = myAjaxObject.responseText;
                        var returnJSON = JSON.parse(returnJSONString);
                        var showString = "";
                        for (var i in returnJSON[0]) {
                            showString = showString + "key=" + i + " username=" + returnJSON[0][i].username + " password=" + returnJSON[0][i].password + " age=" + returnJSON[0][i].age + " createDate=" + returnJSON[0][i].createDate + "
";
                        }
                        alert(showString);
                    }
                }
            }
        </script>
    </head>
    <body>
        <input type="button" value="返回List中存String类型的JSON" onclick="getListString()"/>
        <br/>
        <br/>
        <input type="button" value="返回List中存Bean类型的JSON" onclick="getListBean()"/>
        <br/>
        <br/>
        <input type="button" value="返回Map中存String类型的JSON" onclick="getMapString()"/>
        <br/>
        <br/>
        <input type="button" value="返回Map中存Bean类型的JSON" onclick="getMapBean()"/>
        <br/>
    </body>
</html>

View Code

2.2 创建后台处理Action类

package com.clzhang.ssh.demo6;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.*;

import net.sf.json.JSONArray;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;

/**
 * 返回给前台JSON数据，以四种方式 
 * @author Administrator
 *
 */
public class ReturnJSONAction extends ActionSupport {
    public static final long serialVersionUID = 1;
    
    private List<String> lstString = new ArrayList<String>();
    
    public ReturnJSONAction() {
        lstString.add("你今天吃了吗？");
        lstString.add("吃了多吃点");
        lstString.add("没吃回家吃去");
        lstString.add("好好学习");
        lstString.add("天天向上");
    }

    public String listString() throws IOException {
        JSONArray json = JSONArray.fromObject(lstString);
        System.out.println(json.toString());

        ServletActionContext.getResponse().setContentType("text/html");
        ServletActionContext.getResponse().setCharacterEncoding("utf-8");
        ServletActionContext.getResponse().getWriter().printf(json.toString());
        ServletActionContext.getResponse().getWriter().flush();
        ServletActionContext.getResponse().getWriter().close();

        return null;
    }

    public String listBean() throws IOException {
        List<UserInfo> listBean = new ArrayList<UserInfo>();
        
        for(String str: lstString) {
            UserInfo userInfo1 = new UserInfo();
            userInfo1.setUsername(str);
            userInfo1.setPassword("P" + Math.random());
            userInfo1.setAge((int)(Math.random()*10));
            userInfo1.setCreateDate(new SimpleDateFormat("yyyy-MM-dd hh-mm-ss")
                    .format(new Date()));

            listBean.add(userInfo1);
        }

        JSONArray json = JSONArray.fromObject(listBean);
        System.out.println(json.toString());

        ServletActionContext.getResponse().setContentType("text/html");
        ServletActionContext.getResponse().setCharacterEncoding("utf-8");
        ServletActionContext.getResponse().getWriter().printf(json.toString());
        ServletActionContext.getResponse().getWriter().flush();
        ServletActionContext.getResponse().getWriter().close();

        return null;
    }

    public String mapString() throws Exception {
        LinkedHashMap<String, String> mapString = new LinkedHashMap<String, String>();
        int count = 1;
        for(String str: lstString) {
            mapString.put(""+count++, str+count);
        }

        JSONArray json = JSONArray.fromObject(mapString);
        System.out.println(json.toString());

        ServletActionContext.getResponse().setContentType("text/html");
        ServletActionContext.getResponse().setCharacterEncoding("utf-8");
        ServletActionContext.getResponse().getWriter().printf(json.toString());
        ServletActionContext.getResponse().getWriter().flush();
        ServletActionContext.getResponse().getWriter().close();

        return null;
    }

    public String mapBean() throws Exception {
        LinkedHashMap<String, UserInfo> mapString = new LinkedHashMap<String, UserInfo>();

        int count = 1;
        for(String str: lstString) {
            UserInfo userInfo1 = new UserInfo();
            userInfo1.setUsername(str);
            userInfo1.setPassword("P" + Math.random());
            userInfo1.setAge((int)(Math.random()*10));
            userInfo1.setCreateDate(new SimpleDateFormat("yyyy-MM-dd hh-mm-ss")
                    .format(new Date()));

            mapString.put(""+count++, userInfo1);
        }

        JSONArray json = JSONArray.fromObject(mapString);
        System.out.println(json.toString());

        ServletActionContext.getResponse().setContentType("text/html");
        ServletActionContext.getResponse().setCharacterEncoding("utf-8");
        ServletActionContext.getResponse().getWriter().printf(json.toString());
        ServletActionContext.getResponse().getWriter().flush();
        ServletActionContext.getResponse().getWriter().close();

        return null;
    }

    public String execute() throws IOException {
        return null;
    }
}

View Code

2.3 修改配置文件struts.xml

        <action name="getJson" class="com.clzhang.ssh.demo6.ReturnJSONAction">
        </action>

2.4 测试

打开IE，输入地址：http://127.0.0.1:8080/st/ssh/demo6/getJsonFromResp.jsp

2.4.1 按下“返回List中存String类型的JSON”按钮

2.4.2 按下“返回List中存Bean类型的JSON”按钮

2.4.3 按下“返回Map中存String类型的JSON”按钮

2.4.4 按下“返回Map中存Bean类型的JSON”按钮

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原文地址：https://www.cnblogs.com/nayitian/p/3461478.html