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">
    

    <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

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

);
        people1.setName();
        people1.setAddress();
        people2.setName();
        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">
    
    <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

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

);
        people.setName(name);
        people.setAge();
        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">
<action name="getJsonAction2" class="com.shengsiyuan.action.json.GetJsonAction2">
            <result name="success" type="json">

                <param name="excludeProperties">address</param>

            </result>
        </action>
</package>

3、GetJsonAction2.java处理信息的action

;
        ;
        this.address = "beijing";

        return SUCCESS;//由于使用了struts插件我们这里返回success
    }
}

来自为知笔记(Wiz)