Java对【JSON数据的解析】--Gson解析法

Gson和fastjson分别为谷歌和阿里巴巴对JSON数据进行处理封装的jar包

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两者异同点：

相同点：都是根据JSON数据创建相应的类

不同点：
    1.调用方式区别
    谷歌：方法都是非静态的，需要先创建对象，再去调用
    阿里：方法都是静态的，直接用类调用，不需要创建对象

    2.方法区别：
    谷歌：fromJson（参数1，参数2）
    阿里：JSON.parseXX（参数1，参数2）
        具体是parseObject（）还是parseArray（），根据需要定

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要求：解析下面JSON数据

1.String string = “{name:’zhangsan’,age:18}”;

2.String string = “{persons:[{name:’zhangsan’,age:20},{name:’lisi’,age:21},{name:’wangwu’,age:22}]}”;

3.String string = “{no:1,name:’android’,employees:[{name:’zhangsan’,age:20},{name:’lisi’,age:21},{name:’wangwu’,age:22}]}”;

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代码：

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第一题：

package 谷歌和阿里解析JSON数据;

import com.google.gson.Gson;

public class Test {
    public static void main(String[] args) {
        //Gson解析JSON数据
        //1.创建对象Person，有属性：name，age--创建结束
        String string = "{name:'zhangsan',age:18}";

        Gson gson=new Gson();
        Person person=gson.fromJson(string, Person.class);
        System.out.println(person.getName()+","+person.getAge());
    }
}

class Person{
    private String name;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + "]";
    }
    public Person(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }
    public Person() {
        super();
    }

}

运行结果：

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第2题：

package 谷歌和阿里解析JSON数据;

import java.util.ArrayList;

import com.google.gson.Gson;

public class Test2 {
    public static void main(String[] args) {
        //Gson解析时，遇到对象创建对象，这个对象里所有的内容键都作为对象的属性
        //1.创建第一个对象，有属性：persons，且为集合
        //2.persons集合里是对象，设对象为Person
        //3.Person，它有两个属性：name，age
        //4.相应的类创建完毕后，就可以解析了
        String string = "{persons:[{name:'zhangsan',age:20},{name:'lisi',age:21},{name:'wangwu',age:22}]}";

        Gson gson=new Gson();
        Persons persons=gson.fromJson(string, Persons.class);
        System.out.println(persons);
    }
}

class Persons{
    private ArrayList<Person1> persons;

    public ArrayList<Person1> getPersons() {
        return persons;
    }

    public void setPersons(ArrayList<Person1> persons) {
        this.persons = persons;
    }


    @Override
    public String toString() {
        return "Persons [persons=" + persons + "]";
    }

    public Persons(ArrayList<Person1> persons) {
        super();
        this.persons = persons;
    }

    public Persons() {
        super();
    }

}

class Person1{
    private String name;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + "]";
    }
    public Person1(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }
    public Person1() {
        super();
    }
}

运行结果

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第三题：

package 谷歌和阿里解析JSON数据;

import java.util.ArrayList;

import com.google.gson.Gson;

public class Test3 {
    public static void main(String[] args) {
        //1.第一个对象有属性：no，name，employees，且employees为集合
        //2.employees数组中有对象，设该对象为Person
        //3.Person有属性：name，age----创建结束
        String string = "{no:1,name:'android',employees:[{name:'zhangsan',age:20},{name:'lisi',age:21},{name:'wangwu',age:22}]}";

        Gson gson=new Gson();
        Demo demo=gson.fromJson(string, Demo.class);
        System.out.println(demo);
    }
}

class Demo{
    private int no;
    private String name;
    private ArrayList<Person2> employees;
    public int getNo() {
        return no;
    }
    public void setNo(int no) {
        this.no = no;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public ArrayList<Person2> getEmployees() {
        return employees;
    }
    public void setEmployees(ArrayList<Person2> employees) {
        this.employees = employees;
    }
    @Override
    public String toString() {
        return "Demo [no=" + no + ", name=" + name + ", employees=" + employees + "]";
    }
    public Demo(int no, String name, ArrayList<Person2> employees) {
        super();
        this.no = no;
        this.name = name;
        this.employees = employees;
    }
    public Demo() {
        super();
    }

}

class Person2{
    private String name;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + "]";
    }
    public Person2(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }
    public Person2() {
        super();
    }
}

运行结果：