Java对【JSON数据的解析】--Gson解析法

﹏ヽ暗。殇╰゛Y 2022-06-16 04:20 216阅读 0赞

**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

--------------------

**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：**

![这里写图片描述][SouthEast]

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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**  
![这里写图片描述][SouthEast 1]

--------------------

**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：**

![这里写图片描述][SouthEast 2]

![这里写图片描述][SouthEast 3]

[SouthEast]: /images/20220616/efa31f1c546e4e0795698e180e7e7c93.png
[SouthEast 1]: /images/20220616/2e1201ad6cba4706b752c42a493b3029.png
[SouthEast 2]: /images/20220616/ea26292435c849b6926ae9ee4f349ed6.png
[SouthEast 3]: /images/20220616/f03a3fed67ed4ac0975bdbef48bb4c9b.png