使用Jackson完成全局序列化配置

SpringBoot：使用Jackson完成全局序列化配置

一、引入Jackson， pom配置准备

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.14.2</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.14.2</version>
</dependency>

方式一：@Bean注解创建ObjectMapper实现

全局序列化配置类：

@Configuration
public class JsonConfig {

    /**
     * 创建Jackson对象映射器
     *
     * @param builder Jackson对象映射器构建器
     * @return ObjectMapper
     */
    @Bean
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        //序列换成json时,将所有的long变成string.因为js中得数字类型不能包含所有的java long值，超过16位后会出现精度丢失
        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
        objectMapper.registerModule(simpleModule);
        //反序列化的时候如果多了其他属性,不抛出异常
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        //注意：当bean没有属性时产生空的对象而不是报错
        objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS,false);
 
        //日期格式处理
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        return objectMapper;
    }
}

方式二: 重写configureMessageConverters方法

全局序列化配置类：

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.nio.charset.StandardCharsets;
import java.text.SimpleDateFormat;
import java.util.List;

@Configuration
@EnableWebMvc
public class JsonWebMvcConfigurer implements WebMvcConfigurer {

    /**
     * 全局序列化方式
     * @param converters
     */
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        //Jackson的全局序列化方式
        configureJacksonHttpMessageConverter(converters);
    }

    /**
     * Jackson的全局序列化方式
     * @param converters
     */
    private void configureJacksonHttpMessageConverter(List<HttpMessageConverter<?>> converters) {
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        ObjectMapper objectMapper = new ObjectMapper();

        //序列换成json时,将所有的long变成string.因为js中得数字类型不能包含所有的java long值，超过16位后会出现精度丢失
        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
        objectMapper.registerModule(simpleModule);

        //反序列化的时候如果多了其他属性,不抛出异常
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        //日期格式处理
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        converter.setObjectMapper(objectMapper);
        converters.add(converter);
        converters.add(new StringHttpMessageConverter(StandardCharsets.UTF_8));
    }
}