Springboot2.x使用feign自定义Decoder，Advice

- 日理万妓 2023-02-20 07:58 3阅读 0赞

### 1.首先实现服务提供项目\*\*\*\*\*\*\*\* ###

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pom.xml

application.properties

server.port=8081
    spring.application.name=user-service
    server.servlet.context-path=/api

Grade

package com.frank.entity;
    
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    import java.util.List;
    
    /**
     * @author 小石潭记
     * @date 2020/6/25 12:02
     * @Description: ${todo}
     */
    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class Grade {
    
        private int id;
        private String name;
        private List<User> users;
        private String address;
    }

User

package com.frank.entity;
    
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    /**
     * @author 小石潭记
     * @date 2020/6/22 21:42
     * @Description: ${todo}
     */
    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class User {
    
        private int id;
        private String name;
        private int age;
    
    }

ServerController

package com.frank.web;
    
    import com.frank.entity.Grade;
    import com.frank.entity.User;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.*;
    
    /**
     * @author 小石潭记
     * @date 2020/6/22 21:40
     * @Description: ${todo}
     */
    @RestController
    @Slf4j
    public class ServerController {
    
        @GetMapping("/getUserInfo")
        public Map<String,Object> getUserInfo() {
            Map<String,Object> map = new HashMap<>();
            map.put("code", 200);
            map.put("msg", "success");
            map.put("data", new User(1,"小石潭记",26));
            log.info("返回成功数据成功：{},{}", map, new Date());
            return map;
        }
    
        @GetMapping("/getGradeInfo")
        public Map<String,Object> getGradeInfo() {
            Map<String,Object> map = new HashMap<>();
            List<User> users = new ArrayList<>();
            users.add(new User(1,"小石潭记",8));
            users.add(new User(2,"陋室铭",7));
            users.add(new User(3,"桃花源记",9));
            Grade grade = new Grade(1,"二年级",users, "重庆市忠县");
            map.put("code", 200);
            map.put("msg", "success");
            map.put("data", grade);
            log.info("返回geGradeInfo数据成功：{},{}", map, new Date());
            return map;
        }
    
        @GetMapping("/getFailInfo")
        public Map<String,Object> getFailInfo() {
            Map<String,Object> map = new HashMap<>();
            map.put("code", 404);
            map.put("msg", "fail");
            map.put("data", null);
            log.info("返回失败数据成功：{},{}", map, new Date());
            return map;
        }
    }

FeignServerApplication

package com.frank;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    public class FeignServerApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(FeignServerApplication.class, args);
        }
    
    }

服务提供已完成。。。

### 2.feign-client项目\*\*\*\*\*\* ###

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pom.xml

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.3.1.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.frank</groupId>
        <artifactId>feign-client</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>feign-client</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
                <version>2.0.2.RELEASE</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
                <version>2.0.2.RELEASE</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-netflix-hystrix-dashboard</artifactId>
                <version>2.0.0.RELEASE</version>
            </dependency>
    
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
            </dependency>
    
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>2.11.0</version>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    </project>

application.properties

server.port=8082
    spring.application.name=feign-client
    server.servlet.context-path=/client
    # 开启熔断
    #feign.hystrix.enabled=true

MyAdvice

package com.frank.advice;
    
    import com.frank.domain.MyException;
    import com.frank.domain.dto.BaseResponse;
    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.ExceptionHandler;
    import org.springframework.web.bind.annotation.RestControllerAdvice;
    import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;
    
    import javax.servlet.http.HttpServletRequest;
    
    /**
     * @author 小石潭记
     * @date 2020/6/22 21:07
     * @Description: ${todo}
     */
    @RestControllerAdvice
    public class MyAdvice implements ResponseBodyAdvice<Object> {
    
        /**
         * 抛出该自定义异常就会执行该方法
         */
        @ExceptionHandler(value = MyException.class)
        BaseResponse handleMyException(MyException e, HttpServletRequest request){
            return BaseResponse.fail(e.getMessage());
        }
    
        /**
         *  判断哪些需要拦截 return true 就会执行beforeBodyWrite
         */
        @Override
        public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) {
            return true;
        }
    
        /**
         *  经过decoder之后，就会到达这里，返回结果前，可以对结果进行处理
         */
        @Override
        public Object beforeBodyWrite(Object obj, MethodParameter methodParameter, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
            System.out.println("==>beforeBodyWrite:" + obj.toString() + ","
                    + methodParameter);
            return obj;
        }
    }

MyFeignClient

package com.frank.client;
    
    import com.frank.domain.dto.BaseResponse;
    import com.frank.domain.dto.Grade;
    import com.frank.domain.dto.User;
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.stereotype.Component;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    /**
     * @author 小石潭记
     * @date 2020/6/22 21:48
     * @Description: ${todo}
     */
    @FeignClient(
            //服务名
            name = "user-service",
            //服务地址
            url = "http://localhost:8081/api"
    //        ,fallback = UserHihystric.class   暂不开启熔断
    )
    public interface MyFeignClient {
    
        //对应的服务里的接口地址，及请求方式
        @RequestMapping(value = "/getUserInfo", method = RequestMethod.GET)
        @ResponseBody
        BaseResponse getUserInfo();
    
        @RequestMapping(value = "/getGradeInfo", method = RequestMethod.GET)
        @ResponseBody
        BaseResponse getGradeInfo();
    
        @RequestMapping(value = "/getFailInfo", method = RequestMethod.GET)
        @ResponseBody
        BaseResponse getFailInfo();
    
    }

MyDecoder

package com.frank.decoder;
    
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.frank.domain.EnumError;
    import com.frank.domain.MyException;
    import com.frank.domain.dto.BaseResponse;
    import feign.FeignException;
    import feign.Response;
    import feign.Util;
    import feign.codec.DecodeException;
    import feign.codec.Decoder;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Component;
    
    import java.io.IOException;
    import java.lang.reflect.Type;
    
    /**
     * @author 小石潭记
     * @date 2020/6/23 21:09
     * @Description: 自定义feign的正常返回结果
     */
    @Component
    public class MyDecoder implements Decoder {
    
        @Autowired
        private ObjectMapper mapper;
    
        /**
         *  这里统一处理，根据状态码判断返回正常还是异常的，
         *  200返回正常的，其他状态码直接抛出异常
         */
        @Override
        public Object decode(Response response, Type type) throws IOException, DecodeException, FeignException {
            if (response.status() >= 200 && response.status() <= 299) {
                String result = Util.toString(response.body().asReader());
                BaseResponse baseResponse = mapper.readValue(result, BaseResponse.class);
                int code = baseResponse.getCode();
                if (code == 200){
                    return baseResponse;
                }
                throw new MyException(EnumError.BAD_REQUEST);
            }
            throw new MyException(EnumError.OTHER_ERROR);
        }
    }

MyErrorDecoder

package com.frank.decoder;
    
    import com.fasterxml.jackson.core.type.TypeReference;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.frank.domain.EnumError;
    import com.frank.domain.ExceptionInfo;
    import com.frank.domain.MyException;
    import feign.FeignException;
    import feign.Response;
    import feign.Util;
    import feign.codec.ErrorDecoder;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.stereotype.Component;
    
    /**
     * @author 小石潭记
     * @date 2020/6/23 20:53
     * @Description: 自定义feign错误异常处理
     */
    @Configuration
    public class MyErrorDecoder implements ErrorDecoder {
    
        @Override
        public Exception decode(String methodKey, Response response) {
            /*if (response.status() >= 400 && response.status() <= 499) {
                return new MyException(EnumError.BAD_REQUEST);
            }
            if (response.status() >= 500 && response.status() <= 599) {
                return new MyException(EnumError.SERVER_ERROR);
            }
            return new MyException(EnumError.OTHER_ERROR);*/
            try {
                if (response.body() != null) {
                    ObjectMapper mapper = new ObjectMapper();
                    ExceptionInfo exceptionInfo =mapper.readValue(Util.toString(response.body().asReader()),
                            new TypeReference<ExceptionInfo>() {});
                    Class clazz = Class.forName(exceptionInfo.getException());
                    return (Exception) clazz.getDeclaredConstructor(String.class).newInstance(exceptionInfo.getMessage());
                }
    
            } catch (Exception e) {
                e.printStackTrace();
            }
            return FeignException.errorStatus(methodKey, response);
        }
    }

BaseResponse

package com.frank.domain.dto;
    
    import com.fasterxml.jackson.annotation.JsonProperty;
    import lombok.Data;
    
    /**
     * @author 小石潭记
     * @date 2020/6/25 12:19
     * @Description: ${todo}
     */
    
    @Data
    public class BaseResponse<T> {
    
        /**
         * 返回的状态码
         */
        @JsonProperty("code")
        private int code;
    
        /**
         * 返回的信息
         */
        @JsonProperty("msg")
        private String message;
    
        /**
         * 返回的数据
         */
        @JsonProperty("data")
        private T data;
    
        public static BaseResponse success(Object object){
            BaseResponse baseResponse = new BaseResponse();
            baseResponse.setCode(200);
            baseResponse.setMessage("success");
            baseResponse.setData(object);
            return baseResponse;
        }
    
        public static BaseResponse fail(Object object){
            BaseResponse baseResponse = new BaseResponse();
            baseResponse.setCode(404);
            baseResponse.setMessage("fail");
            baseResponse.setData(object);
            return baseResponse;
        }
    }

Grade

package com.frank.domain.dto;
    
    import com.fasterxml.jackson.annotation.JsonProperty;
    import com.frank.domain.dto.User;
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    import java.util.List;
    
    /**
     * @author 小石潭记
     * @date 2020/6/25 12:02
     * @Description: ${todo}
     */
    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class Grade {
    
        @JsonProperty("id")
        private int id;
    
        @JsonProperty("name")
        private String name;
    
        @JsonProperty("users")
        private List<User> users;
    
        @JsonProperty("address")
        private String address;
    }

User

package com.frank.domain.dto;
    
    import com.fasterxml.jackson.annotation.JsonProperty;
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    /**
     * @author 小石潭记
     * @date 2020/6/22 21:42
     * @Description: ${todo}
     */
    @Data
    public class User {
    
        @JsonProperty("id")
        private int id;
    
        @JsonProperty("name")
        private String name;
    
        @JsonProperty("age")
        private int age;
    
    }

EnumError

package com.frank.domain;
    
    
    /**
     * @author 小石潭记
     * @date 2020/6/23 21:01
     * @Description: ${todo}
     */
    public enum EnumError {
    
        SERVER_ERROR(500, "服务器异常,请联系系统运维人员"),
        BAD_REQUEST(400, "请求异常"),
        OTHER_ERROR(404, "系统异常");
    
        private int status;
        private String reason;
        EnumError(int status, String reason){
            this.status = status;
            this.reason = reason;
        }
    
        public int getStatus() {
            return status;
        }
    
        public void setStatus(int status) {
            this.status = status;
        }
    
        public String getReason() {
            return reason;
        }
    
        public void setReason(String reason) {
            this.reason = reason;
        }}

ExceptionInfo

package com.frank.domain;
    
    import lombok.Data;
    
    /**
     * @author 小石潭记
     * @date 2020/6/25 21:10
     * @Description: ${todo}
     */
    @Data
    public class ExceptionInfo{
    
        private Long timestamp;
    
        private Integer status;
        //异常包结构-"com.crazy.cloud.common.exception.DataConflictException"
        private String exception;
        //信息--手机已注册
        private String message;
    
        private String path;
    
        private String error;
    
    }

MyException

package com.frank.domain;
    
    /**
     * @author 小石潭记
     * @date 2020/6/25 14:09
     * @Description: ${todo}
     */
    public class MyException extends RuntimeException{
    
        public MyException(EnumError enumError){
            super(enumError.getReason());
        }
    }

MyHihystric

package com.frank.hihystric;
    
    import com.frank.client.MyFeignClient;
    import com.frank.domain.dto.BaseResponse;
    import com.frank.domain.dto.Grade;
    import com.frank.domain.dto.User;
    
    /**
     * @author 小石潭记
     * @date 2020/6/23 20:31
     * @Description: ${todo}
     */
    //@Component    暂不开启熔断, 全部返回的null，如果需要使用熔断，返回默认的一个对象即可
    public class MyHihystric implements MyFeignClient {
    
        @Override
        public BaseResponse<User> getUserInfo() {
            return null;
        }
    
        @Override
        public BaseResponse<Grade> getGradeInfo() {
            return null;
        }
    
        @Override
        public BaseResponse getFailInfo() {
            return null;
        }
    
    }

ClientController

package com.frank.web;
    
    import com.frank.client.MyFeignClient;
    import com.frank.domain.dto.BaseResponse;
    import com.frank.domain.dto.Grade;
    import com.frank.domain.dto.User;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.Date;
    
    /**
     * @author 小石潭记
     * @date 2020/6/20 21:38
     * @Description: ${todo}
     */
    @RestController
    @Slf4j
    public class ClientController {
    
        @Autowired
        private MyFeignClient userFeignClient;
    
        @GetMapping("/getUserInfo")
        public BaseResponse<User> getUserInfo() {
            BaseResponse<User> successInfo = userFeignClient.getUserInfo();
            log.info("client->getSuccessInfo返回数据：{},{}", successInfo, new Date());
            return successInfo;
        }
    
        @GetMapping("/getGradeInfo")
        public BaseResponse<Grade> getGradeInfo() {
            BaseResponse<Grade> successInfo = userFeignClient.getGradeInfo();
            log.info("client->getGradeInfo返回数据：{},{}", successInfo, new Date());
            return successInfo;
        }
    
        @GetMapping("/getFailInfo")
        public BaseResponse getFailInfo() {
            BaseResponse failInfo = userFeignClient.getFailInfo();
            log.info("client返回失败数据：{},{}", failInfo, new Date());
            return failInfo;
        }
    }

FeignClientApplication

package com.frank;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    
    @SpringBootApplication
    @EnableFeignClients
    //@EnableHystrixDashboard   暂时不开启熔断
    public class FeignClientApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(FeignClientApplication.class, args);
        }
    
    }

启动项目测试：

http://localhost:8082/client/getUserInfo
    
    
    http://localhost:8082/client/getGradeInfo
    http://localhost:8082/client/getFailInfo

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2_size_16_color_FFFFFF_t_70 2][]

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