setCycleDetectionStrategy 防止自包含

 1 package com.wzw.jsonConfig;
 2 
 3 /**
 4  * @ProjectName: Zwen_Demo
 5  * @Package: com.wzw.jsonConfig
 6  * @ClassName: User
 7  * @Author: WangZunWen
 8  * @Description: ${description}
 9  * @Date: 2020/5/4 17:02
10  */
11 public class User {
12     private String username;
13     private Integer age;
14     private  User user = this;
15     
16     //get
17     //set
18     
19 }
20 //错误展示
21 public class Test1 {
22     public static void main(String[] args) {
23         User user = new User();
24         user.setUsername("userName");
25         user.setAge(20);
26         JsonConfig jsonConfig = new JsonConfig();
27         JSONObject json = JSONObject.fromObject(user);
28         System.out.println(json);
29 
30     }
31 }
32 /*
33 Exception in thread "main" net.sf.json.JSONException: There is a cycle in the hierarchy!
34     at net.sf.json.util.CycleDetectionStrategy$StrictCycleDetectionStrategy.handleRepeatedReferenceAsObject(CycleDetectionStrategy.java:97)
35     at net.sf.json.JSONObject._fromBean(JSONObject.java:859)
36     at net.sf.json.JSONObject.fromObject(JSONObject.java:194)
37     at net.sf.json.JSONObject._processValue(JSONObject.java:2793)
38     at net.sf.json.JSONObject._setInternal(JSONObject.java:2817)
39     at net.sf.json.JSONObject.setValue(JSONObject.java:1527)
40     at net.sf.json.JSONObject._fromBean(JSONObject.java:946)
41     at net.sf.json.JSONObject.fromObject(JSONObject.java:194)
42     at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
43     at com.wzw.jsonConfig.Test1.main(Test1.java:22)
44 
45 Process finished with exit code 1
46 */
47 
48 
49 
50 
51 
52 public class Test2 {
53     public static void main(String[] args) {
54         User user = new User();
55         user.setUsername("userName");
56         user.setAge(20);
57         JsonConfig jsonConfig = new JsonConfig();
58         jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);
59         JSONObject json = JSONObject.fromObject(user,jsonConfig);
60         System.out.println(json);
61 
62     }
63 }
64 /*
65 {"user":null,"age":20,"username":"userName"}
66 
67 Process finished with exit code 0
68 */