Jackson.jar的使用记录

Jackson.jar的使用记录

之前一直使用json-lib.jar,近期发现网上说这个jackson.jar比較好

package com.spring.controller;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import org.codehaus.jackson.JsonEncoding;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.ObjectWriter;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class JacksonController {

	@RequestMapping(value="user/jackson", method = {RequestMethod.POST,RequestMethod.GET})
	public ModelAndView PostJsonTest(HttpServletRequest request,HttpServletResponse response) throws IOException{
		ModelAndView mav=new ModelAndView();
		mav.addObject("time", new Date());
		JsonGenerator jsonGenerator = null;
		ObjectMapper objectMapper = new ObjectMapper();
		jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(System.out, JsonEncoding.UTF8);

		//将java对象转为json
		UserJson userJson=new UserJson();
		userJson.setUsername("小米");
		userJson.setId("31231");
		userJson.setPwd("123456");
		userJson.setAge(24);
		userJson.setAddress("广州");
		userJson.setTel(13676586);
		//objectMapper.writeValue(jsonGenerator, userJson);
		String jsonStr = objectMapper.writeValueAsString(userJson);

		//writeObject能够转换java对象，eg:JavaBean/Map/List/Array等
		//jsonGenerator.writeObject(userJson);

		System.out.println("-----json-------");
		String jsonSS="{\"address\":\"广州\",\"id\":\"31231\",\"username\":\"小米\",\"tel\":13676586,\"age\":24,\"pwd\":\"123456\"}";
		System.out.println("--------字符串json-------"+jsonSS);
		System.out.println("------标准jsonStr--------"+jsonStr);
		mav.addObject("jsonStr", jsonStr);
		mav.addObject("jsonss", jsonSS.toString());
		mav.setViewName("json/jackson");

		//将list集合转为json
		List<UserJson> list=new ArrayList<UserJson>();
		for(int i=0;i<5;i++){
			UserJson u3=new UserJson();
			u3.setId("ooo"+i);
			u3.setUsername("小小明"+i);
			u3.setPwd("123456"+i);
			u3.setAge(20+i);
			u3.setAddress("广州"+i);
			u3.setTel(13664+i*i*i);
			list.add(u3);
		}
		String jsonlist = objectMapper.writeValueAsString(list);
		mav.addObject("jsonlist", jsonlist.toString());

		mav.setViewName("json/jackson");
		return mav;
	}

	/**
	 * list转为json数组
	 */
	public String writeListToJsonArray() throws IOException {
	    /*List<Event> list = new ArrayList<Event>(2);
	    list.add(new Event("a1","a2"));
	    list.add(new Event("b1","b2"));*/

		List<String> list = new ArrayList<String>();
	    list.add("A2");
	    list.add("B2");

	    OutputStream out = new ByteArrayOutputStream();
	    ObjectMapper mapper = new ObjectMapper();
	    mapper.writeValue(out, list);
	    byte[] data = ((ByteArrayOutputStream) out).toByteArray();
	    System.out.println(new String(data));
	    String result=new String(data);
	    return result;
	}

	/**
	 * list转为json数组
	 */
	public String writeListToJsonArray2() throws IOException {
		ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
		final ObjectMapper mapper = new ObjectMapper();
		List<String> list = new ArrayList<String>();
	    list.add("A2");
	    list.add("B2");
		String jsonArray = ow.writeValueAsString(list);
		System.out.println(jsonArray);
		return jsonArray;
	}

}

///java对象
class UserJson{
	private String id;
	private String username;
	private String pwd;
	private Integer age;
	private int tel;
	private String address;
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public int getTel() {
		return tel;
	}
	public void setTel(int tel) {
		this.tel = tel;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}

}

list转为json数组（是Java main程序）

package com.main.java.demo;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.ObjectWriter;

public class JacksonDemo {
	public static void main(String args[]) throws IOException{
		//writeListToJsonArray();
		//writeListToJsonArray2();
		//writeListToJsonArray3();
		//writeListToJsonArray4();
		//writeListToJsonArray5();
		writeListToJsonArray6();
	}

	/**
	 * list转为json数组
	 */
	public static String writeListToJsonArray() throws IOException {
	    /*List<Event> list = new ArrayList<Event>(2);
	    list.add(new Event("a1","a2"));
	    list.add(new Event("b1","b2"));*/

		/*List<String> list = new ArrayList<String>();
	    list.add("A2");
	    list.add("B2");*/

		/*List<Integer> list = new ArrayList<Integer>();
	    list.add(12);
	    list.add(45);
	    list.add(5);*/

		List<Float> list = new ArrayList<Float>();
	    list.add((float) 12.32);
	    list.add((float) 45.12);
	    list.add((float) 5.09);

	    OutputStream out = new ByteArrayOutputStream();
	    ObjectMapper mapper = new ObjectMapper();
	    mapper.writeValue(out, list);
	    byte[] data = ((ByteArrayOutputStream) out).toByteArray();
	    System.out.println(new String(data));
	    String result=new String(data);
	    return result;
	}

	/**
	 * list转为json数组
	 */
	public static String writeListToJsonArray2() throws IOException {
			ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
			final ObjectMapper mapper = new ObjectMapper();
			List<String> list = new ArrayList<String>();
		    list.add("A2");
		    list.add("B2");

		    //// Using writeValueAsString
			String jsonArray = ow.writeValueAsString(list);
			System.out.println(jsonArray);
			return jsonArray;
	}

	/**
	 * list转为json数组
	 */
	public static String writeListToJsonArray3() throws IOException {
		ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
		ObjectMapper mapper = new ObjectMapper();
		List<String> list = new ArrayList<String>();
		list.add("A23");
		list.add("B23");

		//// Using Bytes
		byte[] data = mapper.writeValueAsBytes(list);
		String jsonArray = new String(data, "UTF-8");
		System.out.println(jsonArray);
		return jsonArray;
	}

	/**
	 * list转为json数组
	 */
	public static String writeListToJsonArray4() throws IOException {
		ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
		ObjectMapper mapper = new ObjectMapper();
		List<String> list = new ArrayList<String>();
		list.add("A234");
		list.add("B234");

		// Using ByteArrayOutputStream with new String()
		OutputStream os = new ByteArrayOutputStream();
		mapper.writeValue(os, list);
		byte[] data = ((ByteArrayOutputStream) os).toByteArray();
		String jsonArray = new String(data, "UTF-8");
		System.out.println(jsonArray);
		return jsonArray;
	}

	/**
	 * list转为json数组
	 */
	public static String writeListToJsonArray5() throws IOException {
		ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
		ObjectMapper mapper = new ObjectMapper();
		List<String> list = new ArrayList<String>();
		list.add("A2345");
		list.add("B2345");

		// Using ByteArrayOutputStream
		final OutputStream os = new ByteArrayOutputStream();
		mapper.writeValue(os, list);
		String jsonArray = ((ByteArrayOutputStream) os).toString("UTF-8");
		System.out.println(jsonArray);
		return jsonArray;
	}

	/**
	 * list转为json数组
	 */
	public static String writeListToJsonArray6() throws IOException {
		ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
		ObjectMapper mapper = new ObjectMapper();
		List<String> list = new ArrayList<String>();
		list.add("A23456");
		list.add("B23456");

		// Using writeValueAsString
		String jsonArray = mapper.writeValueAsString(list);
		System.out.println(jsonArray);
		return jsonArray;
	}

}

jsp页面：

<%@ 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 'jackson.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 src="<%=basePath%>js/jquery.min.js"></script>

  </head>

  <body>
     <h3>Jackson 解析json</h3>
     <div><p>传过来的标准json字符串-----是一个json对象----</p>${jsonStr}</div>

     <div><p>传过来的json格式字符串-----是一个json对象-----</p>${jsonss}</div>

     <p>本页面造的json格式字符串------要转为json对象才干解析(还不是一个json对象)----</p>
     <div class="jsonHtml">{"address":"广州","id":"31231","username":"小米","tel":13676586,"pwd":"123456","age":24}</div>

     <div><p>传过来的jsonlist-----是一个json数组对象-----</p>${jsonlist}</div>

  </body>
</html>
<script type="text/javascript">
<!--
    $(document).ready(function(){
    /*
    	//解析服务端传过来的标准json
    	var jsonStr=${jsonStr};//是一个json对象
    	alert(jsonStr.username);//能够解析服务端传过来的json字符串。但解析不了页面造的字符串
    	//遍历json标准字符串
    	//var data=eval("("+jsonStr+")");
    	//alert(data.tel);

    	//var jsonss=${jsonss};//是一个json对象,不用转为json对象，否则出错
    	//alert(jsonss);//是一个对象
    	//var item = jQuery.parseJSON(jsonss);
    	//alert(item.address);

    	var jsonHtml = $(".jsonHtml").html();//是一个字符串，要转为json对象
    	//alert(jsonHtml.tel);//解析不了页面造的字符串，但能解析服务端传过来的字符串

    	var item = jQuery.parseJSON(jsonHtml);
    	alert(item.address);
    */	

    //解析listjson
    var jsonlist=${jsonlist};
    alert(jsonlist.length);
    alert(jsonlist[0].username);
    for(var i=0;i<jsonlist.length;i++){
    	alert(jsonlist[i].username);
    }

    });
//-->
</script>