Struts2 returns Json data (using the Struts2 plug-in), jsonstruts2

Struts2 returns Json data (using the Struts2 plug-in), jsonstruts2

This article describes how to use the Struts2 struts2-json-plugin.jar plug-in to return JSON data.

 

1. The main steps are as follows:

1. Copy the struts2-json-plugin.jar plug-in to the project's "/WEB-INF/lib" folder;

2. Compile an Action file;

3. in struts. configure the Action in the xml file. The "<package... /> "must inherit" json-default ". The Result type of the Action is json, that is, type =" json ", and does not correspond to any view resource.

 

Ii. Sample Code:

Action files:

package com.example.action;import java.util.ArrayList;import com.opensymphony.xwork2.ActionSupport;public class StrutsJsonAction extends ActionSupport {    private int i=123;    private String str="str";    private int[] array={1,2,3};    private ArrayList<String> list;        public int getI() {        return i;    }    public void setI(int i) {        this.i = i;    }    public String getStr() {        return str;    }    public void setStr(String str) {        this.str = str;    }    public int[] getArray() {        return array;    }    public void setArray(int[] array) {        this.array = array;    }    public ArrayList<String> getList() {        return list;    }    public void setList(ArrayList<String> list) {        this.list = list;    }    public String execute(){        list = new ArrayList<String>();        list.add("red");        list.add("green");        list.add("yellow");        return SUCCESS;    }}

 

Struts. xml file:

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"><struts>    <package name="json-example" namespace="/" extends="json-default">        <action name="JSONExample" class="com.example.action.StrutsJsonAction">            <result name="success" type="json"/>        </action>    </package></struts>    

Access "http: // localhost: 8080/Struts2_JSON/JSONExample" in the browser, and the result is displayed.

The JSON plugin serializes all serializable Action attributes into JSON data.

 

3. Configure the Result of the JSON type:

Serialization includes the following attributes:

<Result type = "json"> <! -- Disable browser cache --> <param name = "noCache"> true </param> <! -- Set the server response type --> <param name = "contentType"> application/json </param> <! -- All matching expression attribute names will be serialized --> <param name = "includeProperties"> I, str </param> </result>

 

Serialize only the specified Action attribute:

<Result type = "json"> <! -- Disable browser cache --> <param name = "noCache"> true </param> <! -- Set the server response type --> <param name = "contentType"> application/json </param> <! -- Only serialize the specified attribute in the Action --> <param name = "root"> list </param> </result>