Spring Cloud Gateway中全局异常处理的案例

发布时间:2020-10-28 15:09:32 作者:小新
来源:亿速云 阅读:156

小编给大家分享一下Spring Cloud Gateway中全局异常处理的案例,希望大家阅读完这篇文章后大所收获,下面让我们一起去探讨吧!

Spring Cloud Gateway中的全局异常处理不能直接用@ControllerAdvice来处理,通过跟踪异常信息的抛出,找到对应的源码,自定义一些处理逻辑来符合业务的需求。

网关都是给接口做代理转发的,后端对应的都是REST API,返回数据格式都是JSON。如果不做处理,当发生异常时,Gateway默认给出的错误信息是页面,不方便前端进行异常处理。

需要对异常信息进行处理,返回JSON格式的数据给客户端。下面先看实现的代码,后面再跟大家讲下需要注意的地方。

自定义异常处理逻辑:

package com.cxytiandi.gateway.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.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;
/**
 * 自定义异常处理
 * 
 * <p>异常时用JSON代替HTML异常信息<p>
 * 
 * @author yinjihuan
 *
 */
public class JsonExceptionHandler extends DefaultErrorWebExceptionHandler {

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

    /**
     * 获取异常属性
     */
    @Override
    protected Map<String, Object> getErrorAttributes(ServerRequest request, boolean includeStackTrace) {
        int code = 500;
        Throwable error = super.getError(request);
        if (error instanceof org.springframework.cloud.gateway.support.NotFoundException) {
            code = 404;
        }
        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 HttpStatus getHttpStatus(Map<String, Object> errorAttributes) {
        int statusCode = (int) errorAttributes.get("code");
        return HttpStatus.valueOf(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);
        return map;
    }

}

覆盖默认的配置:

package com.cxytiandi.gateway.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;
/**
 * 覆盖默认的异常处理
 * 
 * @author yinjihuan
 *
 */
@Configuration
@EnableConfigurationProperties({ServerProperties.class, ResourceProperties.class})
public class ErrorHandlerConfiguration {

    private final ServerProperties serverProperties;

    private final ApplicationContext applicationContext;

    private final ResourceProperties resourceProperties;

    private final List<ViewResolver> viewResolvers;

    private final ServerCodecConfigurer serverCodecConfigurer;

    public ErrorHandlerConfiguration(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;
    }
    
}

注意点

在org.springframework.boot.autoconfigure.web.reactive.error.DefaultErrorWebExceptionHandler中的getRoutingFunction()方法就是控制返回格式的,原代码如下:

@Override
protected RouterFunction<ServerResponse> getRoutingFunction(
            ErrorAttributes errorAttributes) {
       return RouterFunctions.route(acceptsTextHtml(), this::renderErrorView)
                .andRoute(RequestPredicates.all(), this::renderErrorResponse);
}

这边优先是用HTML来显示的,想用JSON的改下就可以了,如下:

protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes) {
       return RouterFunctions.route(RequestPredicates.all(), this::renderErrorResponse);
}

原始的方法是通过status来获取对应的HttpStatus的,代码如下:

protected HttpStatus getHttpStatus(Map<String, Object> errorAttributes) {
      int statusCode = (int) errorAttributes.get("status");
      return HttpStatus.valueOf(statusCode);
}

如果我们定义的格式中没有status字段的话,这么就会报错,找不到对应的响应码,要么返回数据格式中增加status子段,要么重写,我这边返回的是code,所以要重写,代码如下:

@Override
protected HttpStatus getHttpStatus(Map<String, Object> errorAttributes) {
    int statusCode = (int) errorAttributes.get("code");
    return HttpStatus.valueOf(statusCode);
}

看完了这篇文章,相信你对Spring Cloud Gateway中全局异常处理的案例有了一定的了解,想了解更多相关知识,欢迎关注亿速云行业资讯频道,感谢各位的阅读!

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  2. Spring Cloud Gateway 之 Filter

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