java通过servlet实现restful接口示例

参考原文https://blog.csdn.net/a249130/article/details/81302123
项目结构：

JsonServlet接口:

package com.demo;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONException;
import org.json.JSONObject;

public class JsonServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String page = req.getParameter("page");
// 将数据添加到数组
List<String> newslist = new ArrayList<String>();
if (page == null || page.equals("0")) {
newslist.add("1");
newslist.add("2");
newslist.add("3");
newslist.add("4");
newslist.add("5");
newslist.add("6");
}else {
newslist.add("01");
newslist.add("001");
newslist.add("0001");
newslist.add("00001");
newslist.add("000001");
newslist.add("00000001");
}
// 调用json.jar工具封装json
JSONObject object = new JSONObject();
for(String str : newslist){
try {
object.put(str, str+":"+page);
}catch (JSONException e) {
e.printStackTrace();
}
}
String json = object.toString();
// 输出到界面
System.out.println(json);
resp.setContentType("text/plain");
resp.setCharacterEncoding("gb2312");
PrintWriter out = new PrintWriter(resp.getOutputStream());
out.print(json);
out.flush();
// 更多Json转换使用请看JsonTest类

}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req, resp);
}
}

index.jsp：

<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="getJson" method="get">
<input type="submit" value="点击获取JSON数据"/>
</form>
</body>
</html>

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>JsonTest</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>

<servlet>
<servlet-name>JsonServlet</servlet-name>
<servlet-class>com.demo.JsonServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>JsonServlet</servlet-name>
<url-pattern>/getJson</url-pattern>
</servlet-mapping>
</web-app>

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