Gateway 过滤器，过滤器统一异常处理

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我是靠谱客的博主精明豆芽，最近开发中收集的这篇文章主要介绍Gateway 过滤器，过滤器统一异常处理，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

以下内容，都很重要

请勿忽略

一，配置文件

spring:
  cloud:
    gateway:
      globalcors:
        cors-configurations:        #cors
          '[/**]':
            allowed-headers: "*"
            allowed-origins: "*"
            allowed-methods: "*"
#      discovery:
#        locator:
#          lower-case-service-id: true
#          enabled: true
      routes:
        - id: web-mac
          uri: lb://web-mac
          predicates:
            - Path=/web-mac/**
          filters:
            - StripPrefix=1
            - Token_Mac=true

解释：

一， cors 不多说了，跨域设置

二， discovery

这个当中的 locator.enabled 必须注释掉。

它会影响到过滤的转发功能。

三，属性

id：随便起名字

uri：lb开头，无需更改。web-mac是注册中心的application name（eruake显示大写，配置里用小写没关系）

predicates：匹配规则

filters：过滤器

在使用过滤器时，StripPrefix=1 必须！

Token_Mac 是我的过滤器，True是代表Config中是否开启。

二，过滤器

package com.tenyears.gateway.filter;

/**
 * @description :
 * @auther Tyler
 * @date 2021/8/12
 */

import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;

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


@Component
public class Token_MacGatewayFilterFactory extends AbstractGatewayFilterFactory<Token_MacGatewayFilterFactory.Config> {

    private static final String TOKEN_HEADER="Authorization";
    private static final String TOKEN_IS_INVALID = "Token is invalid";


    public Token_MacGatewayFilterFactory() {
        super(Config.class);
    }

    @Override
    public List<String> shortcutFieldOrder() {
        return Arrays.asList("enabled");
    }

    @Override
    public GatewayFilter apply(Token_MacGatewayFilterFactory.Config config) {
        System.out.println("TokenGatewayFilterFactory begin");
        return (exchange, chain) -> {

            if (!config.isEnabled()) {
                return chain.filter(exchange);
            }

            ServerHttpRequest request = exchange.getRequest();
            
            HttpHeaders headers = request.getHeaders();
            String token = headers.getFirst(TOKEN_HEADER);
            System.out.println("token : "+token);
            if (StringUtils.isEmpty(token) ) {
                throw new RuntimeException(TOKEN_IS_INVALID);
//                response.setStatusCode(HttpStatus.UNAUTHORIZED);
//                return response.setComplete();
            }

            //验证token，这里举个例子
            if (!token.equals("123") ) {
                throw new RuntimeException(TOKEN_IS_INVALID);
//                response.setStatusCode(HttpStatus.UNAUTHORIZED);
//                return response.setComplete();
            }
            System.out.println("TokenGatewayFilterFactory end");
            return chain.filter(exchange);
        };
    }

    public static class Config {
        // 控制是否开启认证
        private boolean enabled;

        public Config() {}

        public boolean isEnabled() {
            return enabled;
        }

        public void setEnabled(boolean enabled) {
            this.enabled = enabled;
        }
    }

}

一，继承自AbstractGatewayFilterFactory

二，过滤器名：Token_MacGatewayFilterFactory

必须 GatewayFilterFactory 结尾！

三，统一异常处理

package com.tenyears.gateway.advice;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.tenyears.model.common.ApiResult;
import org.springframework.boot.web.reactive.error.ErrorWebExceptionHandler;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ResponseStatusException;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

/**
 * @description :
 * @auther Tyler
 * @date 2021/8/12
 */

@Order(-1)
@Configuration
public class GlobalErrorExceptionHandler implements ErrorWebExceptionHandler {

    private final ObjectMapper objectMapper=new ObjectMapper();

    @Override
    public Mono<Void> handle(ServerWebExchange exchange, Throwable ex) {
        ServerHttpResponse response = exchange.getResponse();
        if (response.isCommitted()) {
            return Mono.error(ex);
        }

        // 设置返回JSON
        response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
        if (ex instanceof ResponseStatusException) {
            response.setStatusCode(((ResponseStatusException) ex).getStatus());
        }

        return response.writeWith(Mono.fromSupplier(() -> {
            DataBufferFactory bufferFactory = response.bufferFactory();
            try {
                //返回响应结果
                ApiResult<String> result=new ApiResult<>();
                result.setCodeToFail(ex.getMessage());
                return bufferFactory.wrap(objectMapper.writeValueAsBytes(result));
            }
            catch (JsonProcessingException e) {
                return bufferFactory.wrap(new byte[0]);
            }
        }));
    }
}

filter 抛出的异常，会被GlobalErrorExceptionHandler 统一处理

ApiResult<T>

是我自定义的返回结果。

package com.tenyears.model.common;

/**
 * Created by Tyler on 2017/6/20.
 */

@Data
public class ApiResult<T> {
	public static final String FAIL_CODE = "0";		//失败码
	public static final String SUC_CODE = "1";		//成功码
	public static final String ERROR_CODE = "2";	//错误码
	public static final String SUC_MESSAGE = "Operate successfully";	//成功信息
	public static final String FAIL_MESSAGE = "Operation failure";		//失败信息
	public static final String ERROR_MESSAGE = "System Error";			//错误信息
	public static final String NOACCESS_MESSAGE = "No permission to access this page.";		//无权操作

	/**
	 * 代码
	 * 0 失败
	 * 1 成功
	 * 2 错误
	 * @mock 1
	 */
	private String code = FAIL_CODE;
	/**
	 * 信息（对应code）
	 * Operate successfully
	 * Operation failure
	 * System Error
	 * @mock Operate successfully
	 */
	private String message = FAIL_MESSAGE;
	/**
	 * 模型
	 */
	private T data;

	/**
	 * 当前页（分页时有效）
	 */
	private Integer page_index = -1;
	/**
	 * 条目（分页时有效）
	 */
	private Integer page_size= -1;

	/**
	 * 总页数（分页时有效）
	 */
	private Integer total_pages=-1;
	/**
	 * 总条目数（分页时有效）
	 */
	private Integer total_elements=-1;


	public void setCode(String code, String message) {
		this.code = code;
		this.message = message;
	}

	public void setCodeToSuccessed() {
		this.code = SUC_CODE;
		this.message = SUC_MESSAGE;
	}
	public void setCodeToSuccessed(T data) {
		this.data = data;
		this.code = SUC_CODE;
		this.message = SUC_MESSAGE;
	}
    
	public void setCodeToError(String message) {
		this.code = ERROR_CODE;
		this.message = message;
	}
	
	public void setCodeToError() {
		this.code = ERROR_CODE;
		this.message = ERROR_MESSAGE;
	}

	public void setCodeToFail(String message) {
		this.code = ERROR_CODE;
		this.message = message;
	}

	public void setCodeToFail() {
		this.code = FAIL_CODE;
		this.message = FAIL_MESSAGE;
	}
	
	public void setCodeByNoAccess() {
		this.code = FAIL_CODE;
		this.message = NOACCESS_MESSAGE;
	}

	public boolean isSuccess() {
		return SUC_CODE.equals(code);
	}

}