java利器F Json之Gson（三）

1.看看map的特殊处理：

1.Point.java:

package com.wds.json;

public class Point {
	private int x;
	private int y;
	
	public Point() {
		super();
	}
	public Point(int x, int y) {
		super();
		this.x = x;
		this.y = y;
	}
	
	@Override
	public String toString() {
		return "Point[x="+x+",y="+y+"]";
	}
	public int getX() {
		return x;
	}
	public void setX(int x) {
		this.x = x;
	}
	public int getY() {
		return y;
	}
	public void setY(int y) {
		this.y = y;
	}
}

Student.java:

package com.wds.json;

import java.util.Date;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Student {
	private int id;
	@Expose
	private String name;
	@Expose
	@SerializedName("bir")
	private Date birthDay;
	
	public Student() {
		super();
	}
	public Student(int id, String name, Date birthDay) {
		super();
		this.id = id;
		this.name = name;
		this.birthDay = birthDay;
	}
	@Override
	public String toString() {
		return "Student [birthDay="+birthDay+",id="+id+",name="+name+"]";
	}
	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 Date getBirthDay() {
		return birthDay;
	}
	public void setBirthDay(Date birthDay) {
		this.birthDay = birthDay;
	}
}

  

 

2.测试类：

package com.wds.json;

import java.util.LinkedHashMap;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;

public class GsonTest3 {
	public static void main(String[] args) {
		Gson gson = new GsonBuilder().enableComplexMapKeySerialization()
		.create();
		
		test1(gson);
		System.out.println();
		test2(gson);

	}

	private static void test2(Gson gson) {
		Map<String,Point> map1 = new LinkedHashMap<String,Point>();
		map1.put("a", new Point(5, 6));
		map1.put("b",new Point(8, 8));

		// map => json
		
		String s = gson.toJson(map1);
		System.out.println("map = > json:" + s);

		// json => map
		Map<String,Point> retMap = gson.fromJson(s,
				new TypeToken<Map<String,Point>>() {
				}.getType());
		for (String key : retMap.keySet()) {
			System.out.println("p[key:" + key + ",value:" + retMap.get(key)+"]");
		}
		System.out.println("map1:"+map1);
		System.out.println("map:"+retMap);
	}

	private static void test1(Gson gson) {
		// 使用LinkedHashMap将结果按先进先出顺序排列
		Map<Point, String> map1 = new LinkedHashMap<Point, String>();
		map1.put(new Point(5, 6), "a");
		map1.put(new Point(8, 8), "b");

		// map => json
		
		String s = gson.toJson(map1);
		System.out.println("map = > json:" + s);

		// json => map
		Map<Point, String> retMap = gson.fromJson(s,
				new TypeToken<Map<Point, String>>() {
				}.getType());
		for (Point p : retMap.keySet()) {
			System.out.println("p[key:" + p + ",value:" + retMap.get(p)+"]");
		}
		System.out.println("map1:"+map1);
		System.out.println("map:"+retMap);
	}

}

 3.运行结果：

map = > json:[[{"x":5,"y":6},"a"],[{"x":8,"y":8},"b"]]
p[key:Point[x=5,y=6],value:a]
p[key:Point[x=8,y=8],value:b]
map1:{Point[x=5,y=6]=a, Point[x=8,y=8]=b}
map:{Point[x=5,y=6]=a, Point[x=8,y=8]=b}

map = > json:{"a":{"x":5,"y":6},"b":{"x":8,"y":8}}
p[key:a,value:Point[x=5,y=6]]
p[key:b,value:Point[x=8,y=8]]
map1:{a=Point[x=5,y=6], b=Point[x=8,y=8]}
map:{a=Point[x=5,y=6], b=Point[x=8,y=8]}

 

4.测试类：

package com.wds.json;

import java.util.ArrayList;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class GsonTest4 {

	public static void main(String[] args) {
		Map<String, Object> map = new LinkedHashMap<String, Object>();
		List<Point> points = new ArrayList<Point>();
		points.add(new Point(3, 4));
		points.add(new Point(5, 6));
		points.add(new Point(9, 3));
		List<Student> students = new ArrayList<Student>();
		students.add(new Student(1, "songjiang", new Date()));
		students.add(new Student(2, "lujunyi", new Date()));
		students.add(new Student(3, "linchong", new Date()));
		map.put("points", points);
		map.put("students", students);

		Gson gson = new Gson();
		String json = gson.toJson(map);
		System.out.println("map = > json:" + json+"\n");
		Map<String, Object> retMap = gson.fromJson(json,
				new TypeToken<Map<String, List<Object>>>() {
				}.getType());

		for (String key : retMap.keySet()) {
			System.out.println("key:" + key + " value:" + retMap.get(key));
			if (key.equals("students")) {
				List<Student> stus = (List<Student>) retMap.get(key);
				System.out.println(stus+"\n");
			} else if (key.equals("points")) {
				List<Point> pointss = (List<Point>) retMap.get(key);
				System.out.println(pointss+"\n");
			}
		}
	}

}

运行结果：

map = > json:{"points":[{"x":3,"y":4},{"x":5,"y":6},{"x":9,"y":3}],"students":[{"id":1,"name":"songjiang","bir":"Jun 19, 2013 10:22:20 PM"},{"id":2,"name":"lujunyi","bir":"Jun 19, 2013 10:22:20 PM"},{"id":3,"name":"linchong","bir":"Jun 19, 2013 10:22:20 PM"}]}

key:points value:[{x=3.0, y=4.0}, {x=5.0, y=6.0}, {x=9.0, y=3.0}]
[{x=3.0, y=4.0}, {x=5.0, y=6.0}, {x=9.0, y=3.0}]

key:students value:[{id=1.0, name=songjiang, bir=Jun 19, 2013 10:22:20 PM}, {id=2.0, name=lujunyi, bir=Jun 19, 2013 10:22:20 PM}, {id=3.0, name=linchong, bir=Jun 19, 2013 10:22:20 PM}]
[{id=1.0, name=songjiang, bir=Jun 19, 2013 10:22:20 PM}, {id=2.0, name=lujunyi, bir=Jun 19, 2013 10:22:20 PM}, {id=3.0, name=linchong, bir=Jun 19, 2013 10:22:20 PM}]