list数据转换成String和Object的格式是不一样的

水深无声 2023-02-24 07:53 4阅读 0赞

**引入jar**

<dependency>
    			<groupId>com.alibaba</groupId>
    			<artifactId>fastjson</artifactId>
    			<version>1.2.70</version>
    		</dependency>

**ListFormat.java**

package com.example.demo.util;
    
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONArray;
    import com.alibaba.fastjson.JSONObject;
    import com.example.demo.entity.User;
    
    import java.util.ArrayList;
    import java.util.List;
    
    /** * list数据转换成String和Object的格式是不一样的。 * String值字符串格式，Object是数组格式 */
    public class ListFormat { 
        public static void main(String[] args) throws Exception { 
            List<String> list = new ArrayList<String>();
            list.add("床前明月光，");
            list.add("疑是地上霜。");
            list.add("举头望明月，");
            list.add("低头思故乡。");
    
            //1. list转json字符串格式
            String jsonStr = JSONArray.toJSONString(list);
            System.out.println("list转json字符串格式 = " + jsonStr);
            User u3 = new User();
            u3.setId(1);
            u3.setName("刘德华");
            u3.setObj(jsonStr);
            System.out.println(JSON.toJSONString(u3));
    
            //2. json字符串格式转Object格式
            Object objectData = JSONObject.parse(jsonStr);
            User u = new User();
            u.setId(1);
            u.setName("刘德华");
            u.setObj(objectData);
            System.out.println(JSON.toJSONString(u));
    
            //3. list转Object格式(第1步和第2步的结合)
            Object objectData2 = JSONArray.toJSON(list);
            User u2 = new User();
            u2.setId(1);
            u2.setName("他好帅");
            u2.setObj(objectData2);
            System.out.println(JSON.toJSONString(u2));
        }
    }
    
    
    package com.example.demo.entity;
    
    public class User { 
        private Integer id;
        private String name;
        private Object obj;
    
        public User() { 
        }
    
        public User(Integer id, String name) { 
            this.id = id;
            this.name = name;
        }
    
        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 Object getObj() { 
            return obj;
        }
    
        public void setObj(Object obj) { 
            this.obj = obj;
        }
    
        @Override
        public String toString() { 
            return "User{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    '}';
        }
    }