Spring boot项目设定返回数据为JSON固定格式

1.配置处理json的配置类

package com.test.config;

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

/**
* 该配置类覆盖了原有的HttpMessageConverters处理方式，采用fastjson处理方式
*/
@Configuration
public class WebConfigure extends WebMvcConfigurerAdapter {

@Bean
public HttpMessageConverters useConverters() {

return new HttpMessageConverters(new FastJsonHttpMessageConverter());
}
}

2.创建返回数据格式类

package com.test.entity;

import lombok.AllArgsConstructor;
import lombok.Data;

/**
* 返回json的模板
*/
@Data
@AllArgsConstructor//生成包含所有变量的有参构造函数
public class ResponseTemplate {

Object data;
}

3.编写用于预处理HttpMessageConverters的处理类，并且要作用于所有使用了注解@RequestMapping的controller的方法上

package com.test.config;

import com.test.entity.ResponseTemplate;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

/**
* 用于预处理httpMessageConverter
*/
@ControllerAdvice//作用于controller中使用了注解@RequestMapping的方法
public class DataResponseBodyAdvice implements ResponseBodyAdvice {

@Override
public boolean supports(MethodParameter returnType, Class converterType) {

return true;
}

@Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {

if(returnType.hasMethodAnnotation(ExceptionHandler.class)) {//处理异常，可以再添加一个异常处理的类，用于处理异常返回格式

return body;
} else {

return new ResponseTemplate(body);
}
}
}