jackson

---

mybatis-plus:
  mapper-locations: classpath:xxx/*.xml
  type-aliases-package: com.xxx.xxx
  configuration:
    call-setters-on-nulls: true    # null 显示问题
  global-config: 
     banner: false
     db-config:
        #updateStrategy: ignored   
        table-prefix: T_

---

spring:
  jackson:
    date-format: yyyy-MM-dd HH:mm:ss   # 时间格式化

---

import java.io.IOException;

import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;

/**
 * null 不显示
 * 
 * @author 
 *
 */
@Configuration
public class JacksonConfig {

    @Bean
    @Primary
    @ConditionalOnMissingBean(ObjectMapper.class)
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
            @Override
            public void serialize(Object o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)
                    throws IOException, JsonProcessingException {
                jsonGenerator.writeString("");
            }
        });
        return objectMapper;
    }

    @Bean
    public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter(ObjectMapper objectMapper) {
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
            @Override
            public void serialize(Object param, JsonGenerator jsonGenerator, SerializerProvider paramSerializerProvider)
                    throws IOException {
                jsonGenerator.writeString("");
            }
        });

        MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
        mappingJackson2HttpMessageConverter.setObjectMapper(objectMapper);
        return mappingJackson2HttpMessageConverter;
    }
}