Question

我有一个RESTful Spring Boot API，它有一个注册端点。

在我的@RestController类中，我编写了一个简单的字符串值预处理器，用于修剪和替换仅具有null值的空白字符串。

  @InitBinder
  public void blankStringBinder(WebDataBinder dataBinder) {
    dataBinder.setDisallowedFields("password", "confirmPassword");
    StringTrimmerEditor stringTrimmerEditor = new StringTrimmerEditor(true);
    dataBinder.registerCustomEditor(String.class, stringTrimmerEditor);
  }

但是当我将Postman的数据作为原始JSON提交时，修剪编辑没有进行。我在blankStringBinder方法中设置了一个断点，我发现每次传入的请求都会调用它。

WebDataBinder似乎适用于form-data。有没有办法让它适用于原始的JSON数据？

Answer 1

创建自定义JsonDeserializer：

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonNode;

public class EmptyToNullCustomDeserializer extends JsonDeserializer<String> {
    @Override
    public String deserialize(JsonParser jp, DeserializationContext dc) throws IOException, JsonProcessingException {
        JsonNode node = jp.readValueAsTree();
        if (node.asText().isEmpty()) {
            return null;
        }
        return node.toString();
    }
}

在POJO的每个String上添加此注释：@JsonDeserialize(using = EmptyToNullCustomDeserializer.class)。例如：

@JsonDeserialize(using = EmptyToNullCustomDeserializer.class)
private String content;

<小时/> 修改：

如果你有很多字符串，那就太麻烦了。

为了概括所有字符串，你必须修改EmptyToNullCustomDeserializer：

@Component
public class EmptyToNullCustomDeserializer extends StdDeserializer<String> {
    protected EmptyToNullCustomDeserializer() {
        super(String.class);
    }

    @Override
    public String deserialize(JsonParser jp, DeserializationContext dc) throws IOException, JsonProcessingException {
        JsonNode node = jp.readValueAsTree();
        if (node.asText().isEmpty()) {
            return null;
        }
        return node.toString();
    }
}

创建此组件：

@Component
public class JacksonConfiguration {

    @Autowired
    private EmptyToNullCustomDeserializer emptyToNullCustomDeserializer;

    @Primary
    @Bean
    public Jackson2ObjectMapperBuilder jacksonObjectMapperBuilder(List<Jackson2ObjectMapperBuilderCustomizer> customizers) {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
        for (Jackson2ObjectMapperBuilderCustomizer customizer : customizers) {
            customizer.customize(builder);
        }
        return builder;
    }

    @Bean
    public Jackson2ObjectMapperBuilderCustomizer addEmptyToNullStringDeserialization() {
        return new Jackson2ObjectMapperBuilderCustomizer() {
            @Override
            public void customize(Jackson2ObjectMapperBuilder jacksonObjectMapperBuilder) {
                jacksonObjectMapperBuilder.deserializerByType(String.class, emptyToNullCustomDeserializer);
            }

        };
    }
}

Spring Boot预处理JSON数据

1 个答案: