jackson 問題定位

問題背景：

雲計算Pass平臺版本升級，致使引用的jackson的包直接由1.*升級爲2.* 。在版本1.*中對於字段名與實際json不符的直接忽略了，而在2.*中則會報錯。諸如此類，有較大差別，須要一一排查

---

 

1、配置maven依賴

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.9.5</version>
    </dependency>　

 

https://mvnrepository.com

 

2、測試類

 

 1 package com.example.myspring.transfer;
 2 
 3 import com.example.myspring.App;
 4 import com.fasterxml.jackson.core.JsonProcessingException;
 5 import com.fasterxml.jackson.databind.ObjectMapper;
 6 import org.junit.Test;
 7 
 8 import java.io.IOException;
 9 import java.util.Arrays;
10 import java.util.HashMap;
11 import java.util.Map;
12 
13 public class JacksonTest {
14 
15     private ObjectMapper objectMapper = new ObjectMapper();
16 
17     Map map = new HashMap();
18 
19     @Test
20     public void toJsonTest1() throws JsonProcessingException {
21         // 多種類型能夠先封裝爲Map
22         map.put("alibaba", new App());
23         map.put("tengxun", Arrays.asList("weixin", "wangzherongyao"));
24         map.put("hugh", null);
25         map.put("DOU", "DOU");
26         System.out.println(objectMapper.writeValueAsString(map));
27         // {"alibaba":{},"DOU":"DOU","tengxun":["weixin","wangzherongyao"],"hugh":null}
28     }
29 
30     @Test
31     public void toJsonTest2() throws IOException {
32         // 新加非類Stu屬性six，且值爲null，依然能夠被識別
33         String likeStu = "{\"sto\":\"001\",\"name\":\"xx\", \"six\":null}";
34         Map<String, Object> mock = objectMapper.readValue(likeStu, Map.class); // {"sto":"001","name":"xx","six":null}
35         System.out.println(objectMapper.writeValueAsString(mock));
36     }
37 
38     public static class Stu{
39 
40         private String sto;
41         private String name;
42 
43         public Stu(String sto, String name) {
44             this.sto = sto;
45             this.name = name;
46         }
47 
48         public String getSto() {
49             return sto;
50         }
51 
52         public void setSto(String sto) {
53             this.sto = sto;
54         }
55 
56         public String getName() {
57             return name;
58         }
59 
60         public void setName(String name) {
61             this.name = name;
62         }
63     }
64 }

 

測試結果：

（1）未能復現項目中報錯，推斷與版本號有關聯

（2）2.9.5  版本能夠解析出以上結果；可是切換到 2.7.0 或者 如下版本，又報不一樣的錯

 

3、總結

不一樣版本的jackson存在較大差別，坑較多

 

【參考】https://www.jianshu.com/p/4bd355715419