maven工程的依赖

                
     
      com.alibaba
                 
     
      fastjson
                 
     
      1.2.45
             
    

创建两个实体类 一个是部门类，一个是部门员工类

部门员工类

public class Person {
        private Integer id;    private String name;    private Integer age;    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public Integer getAge() {        return age;    }    public void setAge(Integer age) {        this.age = age;    }    @Override    public String toString() {        return "Person{" +                "id=" + id +                ", name='" + name + '\'' +                ", age=" + age +                '}';    } }

部门类

public class Dept {    private String deptName;    private List
    
      personList;    public String getDeptName() {        return deptName;    }    public void setDeptName(String deptName) {        this.deptName = deptName;    }    public List
     
       getPersonList() {        return personList;    }    public void setPersonList(List
      
        personList) {        this.personList = personList;    }    @Override    public String toString() {        return "Dept{" +                "deptName='" + deptName + '\'' +                ", personList=" + personList +                '}';    }}
      
     
    

对象转为json字符串格式

JSON.toJSONString(Object object)

@Test    public void fun1(){        List
    
      personArrayList = new ArrayList
     
      ();        Person person = new Person();        person.setId(1);        person.setName("张三");        person.setAge(18);        System.out.println(JSON.toJSONString(person));        personArrayList.add(person);        Person person1 = new Person();        person1.setId(2);        person1.setName("李四");        person1.setAge(18);        personArrayList.add(person1);        System.out.println(JSON.toJSONString(person1));        Dept dept = new Dept();        dept.setDeptName("财务部");        dept.setPersonList(personArrayList);        String jsonString = JSON.toJSONString(personArrayList);        System.out.println(jsonString);    }
     
    

控制台的打印

JSON字符串转JavaBean

JSON.parseObject(String text,Class
    
      clazz)
    

@Test    public void fun2(){        String str1="{\"age\":18,\"id\":1,\"name\":\"张三\"}";        System.out.println(JSON.parseObject(str1,Person.class));        String str2="{\"age\":18,\"id\":2,\"name\":\"李四\"}";        System.out.println(JSON.parseObject(str2,Person.class));    }

控制台打印

JSON字符串数组转List集合

JSON.parseArray(String text, Class
    
      clazz)
    

@Test    public void fun3(){        String str="[{\"age\":18,\"id\":1,\"name\":\"张三\"},{\"age\":18,\"id\":2,\"name\":\"李四\"}]";        List
    
      PersonList=JSON.parseArray(str,Person.class);        System.out.println(PersonList);    }
    

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Map集合转json

JSON.toJSONString(Object object)

@Test    public void fun4(){        Map
    
      personMap=new HashMap
     
      ();        Person person = new Person();        person.setId(1);        person.setName("张三");        person.setAge(18);        personMap.put("zhangsan",person);        Person person1 = new Person();        person1.setId(2);        person1.setName("李四");        person1.setAge(18);        personMap.put("lisi",person1);        String json =  JSON.toJSONString(personMap);        System.out.println(json);    }
     
    

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MapJson字符串转Map集合

(Map)JSON.parse(Object object)

@Test    public void fun5(){        String str="{\"lisi\":{\"age\":18,\"id\":2,\"name\":\"李四\"},\"zhangsan\":{\"age\":18,\"id\":1,\"name\":\"张三\"}}";        Map
    
      map = (Map)JSONObject.parse(str);        System.out.println(map.get("lisi"));        System.out.println(map.get("zhangsan"));    }
    

控制台的打印输出