Spring Cloud Gateway配置自定义异常返回

0. 前言

　　最近搞微服务的全家桶，用到的Spring Cloud Gateway 这个组件。需要对这个网关抛出的异常进行自定义。网关的异常处理跟单体SpringBoot的全局异常处理还有点不一样。

　　单体全局异常处理，是采用@RestControllerAdvice 这个注解来实现的。微服务Gateway是采用另外的方式来实现的。

1. 单体自定义异常返回

　　CustomException.java

package com.wunaozai.config.advice;

/**
 * 自定义异常类(运行时异常)
 * @author wunaozai
 * @date 2018-06-27
 */
public class CustomException extends RuntimeException {

    private static final long serialVersionUID = 6304501072268270030L;
    
    public CustomException(String msg) {
        this(500, msg);
    }
    public CustomException(int code, String msg) {
        this(code, msg, null);
    }
    public CustomException(String msg, Object data) {
        this(500, msg, data);
    }
    public CustomException(int code, String msg, Object data) {
        super(msg);
        this.code = code;
        this.msg = msg;
        this.data = data;
    }
    

    /**
     * 异常代码
     */
    private int code;
    /**
     * 异常信息
     */
    private String msg;
    /**
     * 异常调试信息
     */
    private Object data;
    
    /**
     * 异常代码
     * @return code 
     */
    public int getCode() {
        return code;
    }
    /**
     * 异常代码
     * @param code 异常代码
     */
    public void setCode(int code) {
        this.code = code;
    }
    /**
     * 异常信息
     * @return msg 
     */
    public String getMsg() {
        return msg;
    }
    /**
     * 异常信息
     * @param msg 异常信息
     */
    public void setMsg(String msg) {
        this.msg = msg;
    }
    /**
     * 异常调试信息
     * @return data 
     */
    public Object getData() {
        return data;
    }
    /**
     * 异常调试信息
     * @param data 异常调试信息
     */
    public void setData(Object data) {
        this.data = data;
    }
}

　　CustomControllerAdvice.java

package com.wunaozai.config.advice;

import java.util.HashMap;
import java.util.Map;

import org.springframework.ui.Model;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import com.baomidou.mybatisplus.extension.api.R;

/**
 * 控制器Controller异常处理
 * @author wunaozai
 * @Date 2020-03-05
 */
@RestControllerAdvice
public class CustomControllerAdvice {
    
    /**
     * 应用到所有@RequestMapper 注解方法，在其执行之前初始化数据绑定器
     * @param binder
     */
    @InitBinder
    public void initBinder(WebDataBinder binder) {
        
    }
    
    /**
     * 把值绑定到Model中，使全局@RequestMapper可以获取到该值
     * @param model
     */
    @ModelAttribute
    public void addAttributes(Model model) {
        model.addAttribute("Server", "Wunaozai");
    }
    
    @ExceptionHandler(value= {Exception.class, CustomException.class})
    public R<String> errorHandler(Exception ex){
        Map<String, Object> map = new HashMap<>();
        map.put("code", 500);
        map.put("msg", ex.getMessage());
        System.out.println("异常Handler.");
        ex.printStackTrace();
        //System.out.println(resuserService.count());
        return R.failed(ex.getMessage());
    }
}

2. 微服务Gateway自定义异常返回

　　JsonExceptionHandler.java

package com.wunaozai.config.exception;

import java.util.HashMap;
import java.util.Map;

import org.springframework.boot.autoconfigure.web.ErrorProperties;
import org.springframework.boot.autoconfigure.web.ResourceProperties;
import org.springframework.boot.autoconfigure.web.reactive.error.DefaultErrorWebExceptionHandler;
import org.springframework.boot.web.reactive.error.ErrorAttributes;
import org.springframework.cloud.gateway.support.NotFoundException;
import org.springframework.context.ApplicationContext;
import org.springframework.http.HttpStatus;
import org.springframework.web.reactive.function.server.RequestPredicates;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.RouterFunctions;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;

import lombok.extern.slf4j.Slf4j;

/**
 * 序列化
 * @author wunaozai
 * @Date 2020-06-04
 */
@Slf4j
public class JsonExceptionHandler extends DefaultErrorWebExceptionHandler {

    public JsonExceptionHandler(ErrorAttributes errorAttributes, ResourceProperties resourceProperties,
            ErrorProperties errorProperties, ApplicationContext applicationContext) {
        super(errorAttributes, resourceProperties, errorProperties, applicationContext);
    }

    @Override
    protected Map<String, Object> getErrorAttributes(ServerRequest request, boolean includeStackTrace) {
        int code = HttpStatus.INTERNAL_SERVER_ERROR.value();
        Throwable error = super.getError(request);
//        if(error instanceof NotFoundException) {
//            code = HttpStatus.NOT_FOUND.value();
//        }
        return response(code, this.buildMessage(request, error));
    }

    /**
     * 指定响应处理方法为JSON处理的方法
     * @param errorAttributes
     */
    @Override
    protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes) {
        return RouterFunctions.route(RequestPredicates.all(), this::renderErrorResponse);
    }


    /**
     * 根据code获取对应的HttpStatus
     * @param errorAttributes
     */
    @Override
    protected int getHttpStatus(Map<String, Object> errorAttributes) {
        int statusCode = (int) errorAttributes.get("code");
        return statusCode;
    }

    /**
     * 构建异常信息
     * @param request
     * @param ex
     * @return
     */
    private String buildMessage(ServerRequest request, Throwable ex) {
        StringBuilder message = new StringBuilder("Failed to handle request [");
        message.append(request.methodName());
        message.append(" ");
        message.append(request.uri());
        message.append("]");
        if (ex != null) {
            message.append(": ");
            message.append(ex.getMessage());
        }
        return message.toString();
    }

    /**
     * 构建返回的JSON数据格式
     * @param status        状态码
     * @param errorMessage  异常信息
     * @return
     */
    public static Map<String, Object> response(int status, String errorMessage) {
        Map<String, Object> map = new HashMap<>();
        map.put("code", status);
        map.put("message", errorMessage);
        map.put("data", null);
        log.error(map.toString());
        return map;
    }
}

　　ExceptionHandlerConfiguration.java

package com.wunaozai.config.exception;

import java.util.Collections;
import java.util.List;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.web.ResourceProperties;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.reactive.error.ErrorAttributes;
import org.springframework.boot.web.reactive.error.ErrorWebExceptionHandler;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.result.view.ViewResolver;

/**
 * 自定义异常处理<br>
 * https://www.cnblogs.com/viaiu/p/10403557.html
 * @author wunaozai
 * @Date 2020-06-04
 */
@Configuration
@EnableConfigurationProperties({ ServerProperties.class, ResourceProperties.class })
public class ExceptionHandlerConfiguration {

    private final ServerProperties serverProperties;

    private final ApplicationContext applicationContext;

    private final ResourceProperties resourceProperties;

    private final List<ViewResolver> viewResolvers;

    private final ServerCodecConfigurer serverCodecConfigurer;

    public ExceptionHandlerConfiguration(ServerProperties serverProperties, ResourceProperties resourceProperties,
            ObjectProvider<List<ViewResolver>> viewResolversProvider, ServerCodecConfigurer serverCodecConfigurer,
            ApplicationContext applicationContext) {
        this.serverProperties = serverProperties;
        this.applicationContext = applicationContext;
        this.resourceProperties = resourceProperties;
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public ErrorWebExceptionHandler errorWebExceptionHandler(ErrorAttributes errorAttributes) {
        JsonExceptionHandler exceptionHandler = new JsonExceptionHandler(errorAttributes, this.resourceProperties,
                this.serverProperties.getError(), this.applicationContext);
        exceptionHandler.setViewResolvers(this.viewResolvers);
        exceptionHandler.setMessageWriters(this.serverCodecConfigurer.getWriters());
        exceptionHandler.setMessageReaders(this.serverCodecConfigurer.getReaders());
        return exceptionHandler;
    }
}

 　　处理前异常返回

　　自定义后异常返回

 

参考资料: https://www.cnblogs.com/viaiu/p/10403557.html

本文地址: https://www.cnblogs.com/wunaozai/p/13043979.html