用structs2怎样返回json类型数据

使用Servlet返回JSON数据到客户端：

Java代码

package cn.ysh.studio.struts2.json.demo.servlet

import java.io.IOException

import java.io.PrintWriter

import javax.servlet.ServletException

import javax.servlet.http.HttpServlet

import javax.servlet.http.HttpServletRequest

import javax.servlet.http.HttpServletResponse

import net.sf.json.JSONObject

import cn.ysh.studio.struts2.json.demo.bean.User

public class JSON extends HttpServlet {

/**

*

*/

private static final long serialVersionUID = 1L

/**

* The doGet method of the servlet. <br>

*

* This method is called when a form has its tag value method equals to get.

*

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

*/

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html")

PrintWriter out = response.getWriter()

//将要被返回到客户端的对象

User user=new User()

user.setId("123")

user.setName("JSONServlet")

user.setPassword("JSON")

user.setSay("Hello , i am a servlet !")

JSONObject json=new JSONObject()

json.accumulate("success", true)

json.accumulate("user", user)

out.println(json.toString())

// 因为JSON数据在传递过程中是以普通字符串形式传递的，所以我们也可以手动拼接符合JSON语法规范的字符串输出到客户端

// 以下这两句的作用与38-46行代码的作用是一样的，将向客户端返回一个User对象，和一个success字段

// String jsonString="{\"user\":{\"id\":\"123\",\"name\":\"JSONServlet\",\"say\":\"Hello , i am a servlet !\",\"password\":\"JSON\"},\"success\":true}"

// out.println(jsonString)

out.flush()

out.close()

}

/**

* The doPost method of the servlet. <br>

*

* This method is called when a form has its tag value method equals to post.

*

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

*/

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response)

}

}

返回的对象是实体类得对象的话，先把重写实体类的toString方法：

public

String

toString(){

String

json

=

"{属性1:'%s',属性2:'%s',属性3:'%s',属性4:'%s'}"

//如果是int类型就把单引号去掉，把%s改成%d,double就改成%f

return

String.forMat(json,属性1,属性2,属性3,属性4,)

}

这是实体类里面的

在Action里面使用out.print()打印输出对象的行了，返回return

null

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