Spring Boot配置 jackson 序列化一系列的参数

package net.jinwei.config.converters;


import com.alibaba.fastjson.serializer.SerializeConfig;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
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.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;


import java.math.BigDecimal;
import java.nio.charset.Charset;
import java.util.List;




/**
 * 功能简要
 * 消息转换配置
 *
 * @author xbcui
 * createTime 2021/12/24 9:52 AM
 */
@Configuration
@EnableWebMvc
public class JinWeiConvertersConfigurer  implements WebMvcConfigurer {
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        //在json转换之前先进行string转换
        converters.add(new StringHttpMessageConverter());
        //添加json转换
        MappingJackson2HttpMessageConverter jackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
        jackson2HttpMessageConverter.setObjectMapper(new ConvertersJsonMapper());
        converters.add(jackson2HttpMessageConverter);
    }


    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        //过滤swagger
        registry.addResourceHandler("swagger-ui.html")
                .addResourceLocations("classpath:/META-INF/resources/");
        registry.addResourceHandler("/webjars/**")
                .addResourceLocations("classpath:/META-INF/resources/webjars/");
        registry.addResourceHandler("/swagger-resources/**")
                .addResourceLocations("classpath:/META-INF/resources/swagger-resources/");
        registry.addResourceHandler("/swagger/**")
                .addResourceLocations("classpath:/META-INF/resources/swagger*");
        registry.addResourceHandler("/v2/api-docs/**")
                .addResourceLocations("classpath:/META-INF/resources/v2/api-docs/");
    }
}

package net.jinwei.config.converters;


import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;


import java.io.IOException;
import java.lang.reflect.Field;
import java.text.SimpleDateFormat;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.TimeZone;


import static com.fasterxml.jackson.databind.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES;


/**
 * 功能简要
 * 转JSON 空值处理
 *
 * @author xbcui
 * createTime 2021/12/29 5:25 PM
 */
public class ConvertersJsonMapper extends ObjectMapper {
    public ConvertersJsonMapper() {
        super();
        //收到未知属性时不报异常
        this.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);
        this.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        this.setTimeZone(TimeZone.getTimeZone("GMT+8"));

        //Long类型转为String类型
        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
        this.registerModule(simpleModule);
        //处理null时设置的值
        this.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
            @Override
            public void serialize(Object value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
                String fieldName = gen.getOutputContext().getCurrentName();
                try {
                    //反射获取字段类型
                    Field field = gen.getCurrentValue().getClass().getDeclaredField(fieldName);
                    if (Objects.equals(field.getType(), String.class)) {
                        //字符串型空值""
                        gen.writeString("");
                        return;
                    } else if (Objects.equals(field.getType(), List.class)) {
                        //列表型空值返回[]
                        gen.writeStartArray();
                        gen.writeEndArray();
                        return;
                    } else if (Objects.equals(field.getType(), Map.class)) {
                        //map型空值返回{}
                        gen.writeStartObject();
                        gen.writeEndObject();
                        return;
                    } else if(Objects.equals(field.getType(), Long.class)){
                        gen.writeNumber(0);
                        return;
                    }else if (Objects.equals(field.getType(), String[].class)) {
                        //列表型空值返回[]
                        gen.writeStartArray();
                        gen.writeEndArray();
                        return;
                    }
                } catch (NoSuchFieldException e) {
                }
                //默认返回""
                gen.writeString("");
            }
        });
    }
}