SpringBoot ResponseBody返回值处理的实现

SpringBoot ResponseBody返回值处理的实现

1. SpringBoot ResponseBody 返回值中null值处理

@PostMapping(path = "/test", produces = MediaType.APPLICATION_jsON_VALUE)

public Object test() {

JSONObject jsonObject = new JSONObject();

jsonObject.put("test","test");

jsonObject.put("testnull",null);

ApiResponseVo apiResponseVo = new ApiResponseVo();

apiResponseVo.setData(jsonObject );

apiResponseVo.setStatus(0);

return apiResponseVo;

}

接口返回 (想实现将testnull也进行返回) :

{

"data": {

"test": "test"

},

"status": 0

}

import java.nio.charset.Charset;

import java.util.ArrayList;

import java.util.List;

import org.springframework.context.annotation.Configuration;

import org.springframework.http.MediaType;

import org.springframework.http.converter.HttpMessageConverter;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

import com.alibaba.fastjson.serializer.SerializerFeature;

import com.alibaba.fastjson.support.config.FastJsonConfig;

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;

@Configuration

public class fastJsonConfig extends WebMvcConfigurationSupport {

@Override

public void configureMessageConverters(List> converters) {

FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();

FastJsonConfig config = new FastJsonConfig();

config.setSerializerFeatures(

// 保留 Map 空的字段

SerializerFeature.WriteMapNullValue,

// 将 String 类型的 null 转成""

// SerializerFeature.WriteNullStringAsEmpty,

// 将 Number 类型的 null 转成 0

// SerializerFeature.WriteNullNumberAsZero,

// 将 List 类型的 null 转成 []

// SerializerFeature.WriteNullListAsEmpty,

// 将 Boolean 类型的 null 转成 false

// SerializerFeature.WriteNullBooleanAsFalse,

// 避免循环引用

SerializerFeature.DisableCircularReferenceDetect

);

converter.setFastJsonConfig(config);

converter.setDefaultCharset(Charset.forName("UTF-8"));

List mediaTypeList = new ArrayList<>();

// 解决中文乱码问题，相当于在 Controller 上的 @RequestMapping 中加了个属性 produces = "application/json"

mediaTypeList.add(MediaType.APPLICATION_JSON);

converter.setSupportedMediaTypes(mediaTypeList);

converters.add(converter);

}

}

2. 拦截responsebody转json,对数据进行二次处理 (字典转换做案例)

2.1> 设置拦截器

import java.nio.charset.StandardCharsets;

import java.util.List;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.http.converter.HttpMessageConverter;

import org.springframework.http.converter.StringHttpMessageConverter;

import org.springframework.web.servlet.config.annotation.InterceptorRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import com.alibaba.fastjson.serializer.SerializerFeature;

import com.alibaba.fastjson.support.config.FastJsonConfig;

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;

import com.fintell.dp3.manager.interceptor.LogInterceptor;

@Configuration

public class WebMvcConfiguration implements WebMvcConfigurhttp://er {

@Override

public void addInterceptors(InterceptorRegistry registry) {

// 自定义拦截器，添加拦截路径和排除拦截路径

registry.addInterceptor(getLogInterceptor()).addPathPatterns("/**");

}

@Bean

public LogInterceptor getLogInterceptor() {

return new LogInterceptor();

}

/**

* 修改StringHttpMessageConverter默认配置 & Json 默认序列化方式 (改这个方法)

*/

@Override

public void configureMessageConverters(List> converters) {

//创建fastJson消息转换器

FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();

//创建配置类

FastJsonConfig fastJsonConfig = new FastJsonConfig();

//修改配置返回内容的过滤

fastJsonConfig.setSerializerFeatures(

SerializerFeature.DisableCircularReferenceDetect,

SerializerFeature.WriteMapNullValue,

SerializerFeature.WriteNullStringAsEmpty

);

fastConverter.setFastJsonConfig(fastJsonConfig);

//将fastjson添加到视图消息转换器列表内

converters.add(fastConverter);

}

}

2.2> 字典注解类

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

@Target({ElementType.FIELD})

@Retention(RetentionPolicy.RUNTIME)

public @interface Dict {

String type();

}

2.3> 序列化类

import java.io.IOException;

import java.lang.reflect.Field;

import org.apache.commons.lang3.StringUtils;

import org.springframework.context.annotation.Configuration;

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 lombok.extern.slf4j.Slf4j;

@Slf4j

@Configuration

public class DictJsonSerializer extends JsonSerializer

@Override

public void serialize(Object dictVal, JsonGenerator generator, SerializerProvider provider) throws IOException {

ObjectMapper objectMapper = new ObjectMapper();

String currentName = generator.getOutputContext().getCurrentName();

try {

// 1> 获取字段

Field field = generator.getCurrentValue().getClass().getDeclaredField(currentName);

dwxIzirOe// 2> 获取字典注解

Dict dict = field.getDeclaredAnnotation(Dict.class);

// 3> 判断是否添加了字典注解

if(dict == null) {

objectMapper.writeValue(generator, dictVal);

return;

}

// 4> 获取注解的type值

String type = dict.type();

// **************** 以下依据实际业务处理即可 ********************

// 5> 获取到字段的值

String val = dictVal == null ? "" : dictVal.toString();

String dictValName = "";

if(!StringUtils.isEmpty(val)) {

// 6> 这里可以依据type做不同的处理逻辑

dictValName = "通过自己的方法,依据val获取到对应的字典值";

}

// 7> 将字段改写为{"code":"code","name":"name"}格式

objectMapper.writeValue(generator, BaseEnum.builder().code(dictVal).name(dictValName.toString()).build());

} catch (NoSuchFieldException e) {

log.error(e);

}

}

}

2.4> 字典注解使用

@SuppressWarnings("serial")

@Builder

@Getter

@Setter

@ToString

@NoArgsConstructor

@AllArgsConstructor

public class BizRuleDto implements Serializable{

// 指定使用哪种序列化

@JsonSerialize(using = DictJsonSerializer.class)

// 指定字典 (将被转换为{"code":"content","name":"contentname"}格式)

@Dict(type = "content")

private String content;

}

3. 其它补充 (从容器中获取某个实例) : 如 DictJsonSerializer 需要通过service查询数据库获取字典

@Slf4j

public class DictJsonSerializer extends JsonSerializer

// service

private static ProductProxy productProxy;

static {

productProxy = SpringUtils.getBean(ProductProxy.class);

}

@Override

public void serialize(Object dictVal, JsonGenerator generator, SerializerProvider provider) throws IOException {

}

}

SpringUtils

import org.springframework.beans.BeansException;

import org.springframework.context.ApplicationContext;

import org.springframework.context.ApplicationContextAware;

import org.springframework.stereotype.Component;

@Component

public class SpringUtils implements ApplicationContextAware {

private static ApplicationContext ctx;

/**

* 获取bean

*/

@SuppressWarnings("unchecked")

public static T getBean(String id) {

return (T) ctx.getBean(id);

}

/**

* 按类型获取bean

*/

public static T getBean(Class clazz) {

return ctx.getBean(clazz);

}

@Override

public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

ctx = applicationContext;

}

}

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