SpringBoot @RestControllerAdvice注解对返回值统一封装的处理方法

public interface IStatusCode {

    int getCode();

    String getMsg();
}

import lombok.AllArgsConstructor;
import lombok.Getter;

@Getter
@AllArgsConstructor
public enum ResultCodeEnum implements IStatusCode {

    SUCCESS(1000, "请求成功"),
    FAILED(1001, "请求失败"),
    VALIDATE_ERROR(1002, "参数校验失败"),
    RESPONSE_PACK_ERROR(1003, "response返回包装失败");

    private int code;
    private String msg;
}

import lombok.AllArgsConstructor;
import lombok.Getter;

@Getter
@AllArgsConstructor
public enum BusinessCodeEnum implements IStatusCode {

    APP_ERROR(2000, "业务异常"),
    PRICE_ERROR(2001, "价格异常");

    private int code;
    private String msg;
}

import lombok.Getter;

@Getter
public class BusinessException extends RuntimeException {

    private int code;

    private String msg;

    // 手动设置异常
    public BusinessException(IStatusCode codeEnum, String message) {
        // message用于用户设置抛出错误详情
        super(message);
        // 状态码
        this.code = codeEnum.getCode();
        // 状态码配套的msg
        this.msg = codeEnum.getMsg();
    }

    // 默认异常使用APP_ERROR状态码
    public BusinessException(String message) {
        super(message);
        this.code = BusinessCodeEnum.APP_ERROR.getCode();
        this.msg = BusinessCodeEnum.APP_ERROR.getMsg();
    }
}

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface NotControllerResponseAdvice {
}

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

import java.util.Arrays;
import java.util.List;

// 对指定包下面的Controller进行增强
@RestControllerAdvice(basePackages = {"com.example.jmw.controller"})
public class ControllerResponseAdvice implements ResponseBodyAdvice<Object> {

    @Override
    public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> converterType) {

        List<Boolean> judgeResultList = Arrays.asList(
                // ⭕判断相应的类型是否为ResultVo类型
                methodParameter.getParameterType().isAssignableFrom(ResultVo.class),
                // ⭕判断响应的方法上是否包含 NotControllerResponseAdvice 注解
                methodParameter.hasMethodAnnotation(NotControllerResponseAdvice.class)
        );

        // 若包含其中一项,则不进行封装
        return !judgeResultList.contains(true);
    }

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

        // String类型不能直接包装
        if (returnType.getGenericParameterType().equals(String.class)) {
            ObjectMapper objectMapper = new ObjectMapper();
            try {
                // 将数据包装在ResultVo里后转换为json串进行返回
                return objectMapper.writeValueAsString(ResultVo.build(body));
            } catch (JsonProcessingException e) {
            	// 抛出自定义的业务异常
                throw new BusinessException(ResultCodeEnum.RESPONSE_PACK_ERROR, e.getMessage());
            }
        }

        // 否则直接包装成ResultVo返回
        return ResultVo.build(body);
    }
}

@Controller
@RequestMapping("/test12")
public class Test12Controller {

    @PostMapping("/test")
    @ResponseBody
    public List<String> test() {

        return Arrays.asList("1", "2", "3");
    }
}