定製解串器從來沒有所謂

Question

這是我所使用的@JsonDeserialize

@Transient 
@JsonDeserialize(using = SharedUserDeserializer.class) 
private Set<UserVehicleMappingVO> sharedVehicle; 

public Set<UserVehicleMappingVO> getSharedVehicle() { 
    return sharedVehicle; 
} 
public void setSharedVehicle(Set<UserVehicleMappingVO> sharedVehicle) { 
    this.sharedVehicle = sharedVehicle; 
} 

而定製的解串器代碼的屬性是

public class SharedUserDeserializer extends JsonDeserializer<Set<UserVehicleMappingVO>> { 

@Override 
public Set<UserVehicleMappingVO> deserialize(JsonParser paramJsonParser, 
     DeserializationContext paramDeserializationContext) 
     throws IOException, JsonProcessingException { 
    try { 
     Set<UserVehicleMappingVO> list = new ObjectMapper().readValue(paramJsonParser.toString(), 
       new TypeReference<Set<UserVehicleMappingVO>>() {}); 
     return list; 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return new HashSet<>(); 
} 
} 

但解串器永遠不會被調用。請幫助

每次我得到這個異常，而不是....

ERROR :::9,gajendranc@azuga.com - Exception in 
method===org.springframework.validation.BeanPropertyBindingResult: 1 errors 
Field error in object 'trackee' on field 'sharedVehicle': rejected value 
[[{"userId":"5d48b74f-7da2-11e7-87bf- 
1383429d1d89","expireTime":1504190100000}]]; codes 
[typeMismatch.trackee.sharedVehicle,typeMismatch.sharedVehicle, 
typeMismatch.java.util.Set,typeMismatch]; arguments 
[org.springframework.context.support.DefaultMessageSourceResolvable: codes 
[trackee.sharedVehicle,sharedVehicle]; arguments []; default message 
[sharedVehicle]]; default message [Failed to convert property value of type 
[java.lang.String] to required type [java.util.Set] for property 
'sharedVehicle'; nested exception is java.lang.IllegalStateException: Cannot 
convert value of type [java.lang.String] to required type 
[com.azuga.user.manager.UserVehicleMappingVO] for property 
'sharedVehicle[0]': 

請幫助........

Answer 1

嘗試反序列化唯一的 「設置」 - >擴展JsonDeserializer <集>

Answer 2

您是否註冊了本示例中提到的模塊http://www.baeldung.com/jackson-deserialization？

 ObjectMapper mapper=new ObjectMapper(); 
     SimpleModule module = new SimpleModule(); 

     module.addDeserializer(Set.class, new SharedUserDeserializer()); 
     mapper.registerModule(module); 

這是爲我工作：

@Test 
    public void test() throws IOException { 

     ObjectMapper mapper=new ObjectMapper(); 
     SimpleModule module = new SimpleModule(); 

     module.addDeserializer(Set.class, new SharedUserDeserializer()); 
     mapper.registerModule(module); 
     TestUser user=new TestUser(); 

    Set<UserVehicleMappingVO> sets=new HashSet<>(); 

    sets.add(new UserVehicleMappingVO("test1")); 
    user.setVechicles(sets); 

    String jsonString=mapper.writeValueAsString(user); 
    Set<UserVehicleMappingVO> vechiles=mapper.readValue(jsonString, new TypeReference<Set<UserVehicleMappingVO>>() { 
    }); 

} 

型號：

public class TestUser { 

    @JsonDeserialize(using = SharedUserDeserializer.class) 
    private Set<UserVehicleMappingVO> vechicles; 
    //getters and setters 
} 

public class UserVehicleMappingVO { 

    private String name; 

//getters and setters 

} 

自定義解串器類：

public class SharedUserDeserializer extends JsonDeserializer<Set<UserVehicleMappingVO>> { 

@Override 
public Set<UserVehicleMappingVO> deserialize(JsonParser paramJsonParser, 
     DeserializationContext paramDeserializationContext) 
     throws IOException, JsonProcessingException { 
    try { 
     System.out.println("hello"); 
     Set<UserVehicleMappingVO> list = new ObjectMapper().readValue(paramJsonParser.toString(), 
       new TypeReference<Set<UserVehicleMappingVO>>() {}); 
     return list; 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return new HashSet<>(); 
} 

響應：

Output {"vechicles":[{"name":"test1"}]} 
hello 

定製HttpMessageConverters：

@Bean 
public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() { 
MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter(); 
ObjectMapper objectMapper = new ObjectMapper(); 
SimpleModule module = new SimpleModule(); 

      module.addDeserializer(Set.class, new SharedUserDeserializer()); 
      objectMapper.registerModule(module); 

jsonConverter.setObjectMapper(objectMapper); 
return jsonConverter; 
} 

參考這裏：https://dzone.com/articles/customizing