文章目录

• Jackson处理序列化转换的方式
• • 细粒度，范围具体字段 @JsonSerialize
  • 作用范围，根据字段命名或类型
  • 全局转换 ObjectMapper
  • jackson2 应用全局配置

Jackson处理序列化转换的方式

细粒度，范围具体字段 @JsonSerialize

指定当前字段使用 ToStringSerializer 序列化

    @JsonSerialize(using = ToStringSerializer.class)
    private Long id;

作用范围，根据字段命名或类型

指定范围Long类型转换为String

public class Long2StringJacksonConverter extends JsonSerializer<Long> {
    @Override
    public void serialize(Long value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
        // currentName 为当前字段名
        String currentName = jsonGenerator.getOutputContext().getCurrentName();
        String text = (value == null ? null : String.valueOf(value));
        if (text != null) {
            jsonGenerator.writeString(text);
        }
    }
    // 指定转换器所属类型，key为class类型
    @Override
    public Class<Long> handledType() {
        return Long.class;
    }
}

jackson2ObjectMapperFactoryBean 注册序列化

@Configuration
public class ConverterConfig {
    @Bean
    public DateJacksonConverter dateJacksonConverter() {
        return new DateJacksonConverter();
    }
    @Bean
    public Long2StringJacksonConverter long2StringJacksonConverter() {
        return new Long2StringJacksonConverter();
    }
    @Bean
    public Jackson2ObjectMapperFactoryBean jackson2ObjectMapperFactoryBean(
            @Autowired
                    Long2StringJacksonConverter long2StringJacksonConverter) {
        Jackson2ObjectMapperFactoryBean jackson2ObjectMapperFactoryBean = new Jackson2ObjectMapperFactoryBean();
        jackson2ObjectMapperFactoryBean.setSerializers(long2StringJacksonConverter);
        return jackson2ObjectMapperFactoryBean;
    }
}

全局转换 ObjectMapper

ObjectMapper 注册 module 模块

@Configuration
public class ConverterConfig {

    @Bean
    public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter(
            @Autowired
                    ObjectMapper objectMapper) {
        MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter =
                new MappingJackson2HttpMessageConverter();

        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
        objectMapper.registerModule(simpleModule);
        mappingJackson2HttpMessageConverter.setObjectMapper(objectMapper);
        return mappingJackson2HttpMessageConverter;
    }
}

jackson2 应用全局配置

Jackson2ObjectMapperBuilderCustomizer 自定义 ObjectMapper 建造其器

@Configuration
public class JacksonConfig {
 
	/**
	 * Jackson全局转化long类型为String，解决jackson序列化时long类型缺失精度问题
	 * @return Jackson2ObjectMapperBuilderCustomizer 注入的对象
	 */
	@Bean
	public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
		Jackson2ObjectMapperBuilderCustomizer cunstomizer = new Jackson2ObjectMapperBuilderCustomizer() {
			
			@Override
			public void customize(Jackson2ObjectMapperBuilder jacksonObjectMapperBuilder) {
 
				jacksonObjectMapperBuilder.serializerByType(Long.TYPE, ToStringSerializer.instance);
				jacksonObjectMapperBuilder.serializerByType(Long.class, ToStringSerializer.instance);

			}
		};
		
		return cunstomizer;
	}