Gson-序列化案例

本文介绍如何使用Gson将数组，集合和泛型进行序列化/反序列化。

1 Gson处理数组

1.1 编写核心类

MainApp：

package com.yiidian.gson;

import com.google.gson.Gson;
import java.util.Arrays;

/**
 * 一点教程网 - http://www.yiidian.com
 */
public class MainApp {

    public static void main(String args[]) {

        Gson gson = new Gson();
        int[] marks = {100,90,85};
        String[] names = {"eric","jack","rose"};

        //序列化
        System.out.print("{");
        System.out.print("marks:" + gson.toJson(marks) + ",");
        System.out.print("names:" + gson.toJson(names));
        System.out.println("}");

        //反序列化
        marks = gson.fromJson("[100,90,85]", int[].class);
        names = gson.fromJson("[\"eric\",\"jack\",\"rose\"]", String[].class);
        System.out.println("marks:" + Arrays.toString(marks));
        System.out.println("names:" + Arrays.toString(names));
    }

}

1.2 运行测试

2 Gson处理集合

2.1 编写核心类

MainApp：

package com.yiidian.gson;

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

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;

/**
 * 一点教程网 - http://www.yiidian.com
 */
public class MainApp {

    public static void main(String args[]) {

        Gson gson = new Gson();
        Collection<Integer> marks = new ArrayList<Integer>();
        marks.add(100);
        marks.add(90);
        marks.add(85);

        //序列化
        System.out.print("{");
        System.out.print("marks:" + gson.toJson(marks));
        System.out.println("}");

        //反序列化
        Type listType = new TypeToken<Collection<Integer>>(){}.getType();
        marks = gson.fromJson("[100,90,85]", listType);
        System.out.println("marks:" +marks);
    }

}

2.2 运行测试

3 Gson处理泛型

3.1 编写核心类

MainApp：

package com.yiidian.gson;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.Type;

/**
 * 一点教程网 - http://www.yiidian.com
 */
public class MainApp {

    public static void main(String args[]) {

        //创建Shape对象
        Shape<Circle> shape = new Shape<Circle>();

        //创建Circle对象
        Circle circle = new Circle(5.0);

        //把circle对象赋值给shape
        shape.setShape(circle);
        Gson gson = new Gson();

        Type shapeType = new TypeToken<Shape<Circle>>() {}.getType();

        //序列化
        String jsonString = gson.toJson(shape, shapeType);
        System.out.println(jsonString);
        Shape shape1 = gson.fromJson(jsonString, Shape.class);

        System.out.println(shape1.get().getClass());
        System.out.println(shape1.get().toString());
        System.out.println(shape1.getArea());
        Shape shape2 = gson.fromJson(jsonString, shapeType);
        System.out.println(shape2.get().getClass());
        System.out.println(shape2.get().toString());
        System.out.println(shape2.getArea());
    }

}

class Shape <T> {
    public T shape;

    public void setShape(T shape) {
        this.shape = shape;
    }
    public T get() {
        return shape;
    }
    public double getArea() {
        if(shape instanceof Circle) {
            return ((Circle) shape).getArea();
        } else {
            return 0.0;
        }
    }
}

class Circle {
    private double radius;

    public Circle(double radius){
        this.radius = radius;
    }
    public String toString() {
        return "Circle";
    }
    public double getRadius() {
        return radius;
    }
    public void setRadius(double radius) {
        this.radius = radius;
    }
    public double getArea() {
        return (radius*radius*3.14);
    }
}

3.2 运行测试