Struts2实现异步调用机制详细剖析（XML和JSON）

一、使用XML传递

1、页面展示getXML.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
 
    <title>My JSP 'getXML.jsp' starting page</title>
 
    <script type="text/javascript" src="scripts/jquery-1.4.4.js"></script>
 
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">   
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
 
    <script type="text/javascript">
 
    function getInfo()
    {
        $.post("getXMLAction.action",
        {
            name: $("#name").val()//像后台getXMLAction.action中传递name值
        },function(returnedData, status)
        {
            var id = $(returnedData).find("id").text();//使用find函数取得后台传递的XML信息
            var name = $(returnedData).find("name").text();
            var age = $(returnedData).find("age").text();
            var address = $(returnedData).find("address").text();
 
            var html = "<table width='60%' border='1' align='center'><tr><th>id</th><th>name</th><th>age</th><th>address</th><tr align='center'><td>" + id + "</td><td>" + name + "</td><td>" + age + "</td><td>" + address + "</td></tr></table>";
 
            $("#theBody table:eq(0)").remove();//表示每次将table表格中的第一行清除掉，进行添加，显示为每次显示一条结果
 
            $("#theBody").append(html);
        });       
    }
    </script>
 
  </head>
 
    <body id="theBody">
 
   <select id="name">
 
    <option value="zhangsan">zhangsan</option>
    <option value="lisi">lisi</option>
 
   </select>  
 
    <input type="button" value="get information" onclick="getInfo();">
  </body>
</html>
2、配置struts
<action name="getXMLAction" class="com.shengsiyuan.action.xml.GetXMLAction">
</action>
3、bean对象Person.java
package com.shengsiyuan.action.xml;
 
public class People
{
    private int id;
 
    private String name;
 
    private int age;
 
    private String address;
 
    public int getId()
    {
        return id;
    }
 
    public void setId(int id)
    {
        this.id = id;
    }
 
    public String getName()
    {
        return name;
    }
 
    public void setName(String name)
    {
        this.name = name;
    }
 
    public int getAge()
    {
        return age;
    }
 
    public void setAge(int age)
    {
        this.age = age;
    }
 
    public String getAddress()
    {
        return address;
    }
 
    public void setAddress(String address)
    {
        this.address = address;
    }
}
4、GetXMLAction.java用于处理请求和返回请求
package com.shengsiyuan.action.xml;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import com.opensymphony.xwork2.ActionSupport;
public class GetXMLAction extends ActionSupport
{
    private String name;
 
    public String getName()
    {
        return name;
    }
 
    public void setName(String name)
    {
        this.name = name;
    }
 
    @Override
    public String execute() throws Exception
    {
        //zhang san
        People people1 = new People();
 
        people1.setId(1);
        people1.setName("zhangsan");
        people1.setAge(30);
        people1.setAddress("beijing");
 
        People people2 = new People();
 
        people2.setId(2);
        people2.setName("lisi");
        people2.setAge(50);
        people2.setAddress("tianjin");
 
        Document document = DocumentHelper.createDocument();//dom4j中的document对象
 
        Element rootElement = document.addElement("persons");//使用element来定义XML
 
        rootElement.addComment("This is comment!!");
 
        Element e = rootElement.addElement("person");//根元素为person
 
        Element idElement = e.addElement("id");//子元素对应关系
        Element nameElement = e.addElement("name");
        Element ageElement = e.addElement("age");
        Element addressElement = e.addElement("address");
 
        if("zhangsan".equals(name))
        {
            idElement.setText(people1.getId() + "");
            nameElement.setText(people1.getName());
            ageElement.setText(people1.getAge() + "");
            addressElement.setText(people1.getAddress());
        }
        else
        {
            idElement.setText(people2.getId() + "");
            nameElement.setText(people2.getName());
            ageElement.setText(people2.getAge() + "");
            addressElement.setText(people2.getAddress());
        }
 
        HttpServletResponse response = ServletActionContext.getResponse();
 
        response.setContentType("text/xml; charset=utf-8");
        response.setHeader("cache-control", "no-cache");
 
        PrintWriter out = response.getWriter();
 
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("utf-8");
 
        XMLWriter writer = new XMLWriter(out, format);
 
        writer.write(document);
 
        out.flush();
        out.close();
 
        return null;//返回空值，这里对应struts处无result对应的返回值
    }
}
5、对应的XML输出信息
 

二、使用json异步获取信息

1、页面getJson.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
 
    <title>My JSP 'json.jsp' starting page</title>
 
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">   
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
    <script type="text/javascript" src="scripts/jquery-1.4.4.js"></script>
 
    <script type="text/javascript">
 
    $(function()
    {
        $("#button1").click(function()
        {
            $.post("getJsonAction2.action",{name: $("#name").val()},
                function(returnedData, status)
            {
                var people = returnedData;
 
                var id = people.id;
                var name = people.name;
                var age = people.age;
                var address = people.address;
 
                var html = "<table width='60%' border='1' align='center'><tr><th>id</th><th>name</th><th>age</th><th>address</th><tr align='center'><td>" + id + "</td><td>" + name + "</td><td>" + age + "</td><td>" + address + "</td></tr></table>";
 
                $("#theBody table:eq(0)").remove();
 
                $("#theBody").append(html);
 
            });           
        });
    });
 
    </script>
 
 
  </head>
 
  <body id="theBody">
 
   <select id="name">
 
    <option value="zhangsan">zhangsan</option>
    <option value="lisi">lisi</option>
 
   </select> 
 
 
    <input type="button" value="get json content from server" id="button1">
 
  </body>
</html>
2、struts控p制层
        <action name="getJsonAction" class="com.shengsiyuan.action.json.GetJsonAction">
        </action>
3、bean对象Person.java见使用XML获取后台信息
4、GetJsonAction.java处理信息的action
package com.shengsiyuan.action.json;
 
import java.io.PrintWriter;
 
import javax.servlet.http.HttpServletResponse;
 
import org.apache.struts2.ServletActionContext;
 
import com.google.gson.Gson;
import com.opensymphony.xwork2.ActionSupport;
import com.shengsiyuan.action.xml.People;
 
public class GetJsonAction extends ActionSupport
{
    private String name;
 
    public String getName()
    {
        return name;
    }
 
    public void setName(String name)
    {
        this.name = name;
    }
 
    @Override
    public String execute() throws Exception
    {
        People people = new People();
 
        people.setId(1);
        people.setName(name);
        people.setAge(30);
        people.setAddress("beijing");
 
        Gson gson = new Gson();
 
        String result = gson.toJson(people);
 
        HttpServletResponse response = ServletActionContext.getResponse();
 
        response.setContentType("application/json; charset=utf-8");
        response.setHeader("cache-control", "no-cache");
 
        PrintWriter out = response.getWriter();
 
        out.print(result);
 
        out.flush();
        out.close();
 
        return null;
    }
}
5、以下是Json打印出的json数据

三、使用struts插件获得json数据信息

 
此插件解压缩中对应xml文件信息如下：返回一个json的结果于对应的类进行过处理，而且还定义啦一个json拦截器
 
1、页面中和以上页面相同
2、struts配置
<package name="struts2_ajax" extends="json-default"><!-- 其中更改继承为json-default-->
<action name="getJsonAction2" class="com.shengsiyuan.action.json.GetJsonAction2">
            <result name="success" type="json">
 
                <param name="excludeProperties">address</param><!--这里表示你不想传递到页面的变量-->
 
            </result>
        </action>
</package>
 3、GetJsonAction2.java处理​信息的action
package com.shengsiyuan.action.json;
 
import org.apache.struts2.json.annotations.JSON;
 
import com.opensymphony.xwork2.ActionSupport;
 
public class GetJsonAction2 extends ActionSupport
{
    private String name;
 
    private int id;
 
    private int age;
 
    private String address;
 
    public String getName()
    {
        return name;
    }
 
    public void setName(String name)
    {
        this.name = name;
    }
 
    public int getId()
    {
        return id;
    }
 
    public void setId(int id)
    {
        this.id = id;
    }
 
    @JSON(name="myAge")//这里演示的是注解更改为我们想要的名字，那在页面中我们就要用myAge，可以不使用注解
    public int getAge()
    {
        return age;
    }
 
    public void setAge(int age)
    {
        this.age = age;
    }
 
    public String getAddress()
    {
        return address;
    }
 
    public void setAddress(String address)
    {
        this.address = address;
    }
 
    @Override
    public String execute() throws Exception
    {
        this.id = 1;
        this.age = 30;
        this.address = "beijing";
 
        return SUCCESS;//由于使用了struts插件我们这里返回success
    }
}





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原文地址：https://www.cnblogs.com/wang3680/p/3283761.html