SpringBoot中关于Fegin调用报错：failed and no fallback available
首先不能随意导入依赖，因为在openapi-gateway部分里面导入了openapi-cache的依赖以致于我在openapi-gateway里面使用CacheService被认为需要再次使用openapi-cache模块里通过gitee才能连接redis。其次，在CacheService添加下面的注释之后要编写相应的Fallback文件@FeignClient(value ="OPENAPI-
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首先不能随意导入依赖，因为在openapi-gateway部分里面导入了openapi-cache的依赖以致于我在openapi-gateway里面使用CacheService被认为需要再次使用openapi-cache模块里通过gitee才能连接redis。
其次，在CacheService添加下面的注释之后要编写相应的Fallback文件
@FeignClient(value ="OPENAPI-CACHE" ,fallback = CacheServiceFallback.class)CacheServiceFallback代码如下：
package com.zgz.openplatform.gateway.feign;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.*;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
/**
* feign的降级机制，具体实现要一个一个填写
*/
@Component
public class CacheServiceFallback implements CacheService{
//日志在logback-spring.xml里面写好了，这里调用一下
private static Logger logger = LoggerFactory.getLogger(CacheServiceFallback.class);
/**
* 保存数据到缓存中的降级方法
* @param key
* @param value
* @param expireTime
* @return
* @throws Exception
*/
public boolean save2Redis( String key, String value, long expireTime) throws Exception {
logger.error("save2Redis出现异常进行降级,{},{}",key,value); //打印出日志里面记录的异常
return false;
}
public String getFromRedis( String key) throws Exception {
logger.error("getFromRedis出现异常进行降级,{}",key);
return null;
}
public boolean deleteKey( String key) throws Exception {
logger.error("save2Redis出现异常进行降级,{}",key); //打印出日志里面记录的异常
return false;
}
public boolean expire( String key, long expireTime) throws Exception {
logger.error("save2Redis出现异常进行降级,{}",key); //打印出日志里面记录的异常
return false;
}
public Long getAutoIncrementId( String key) throws Exception {
logger.error("getautoincrementidFallBack出现异常进行降级,{}",key); //打印出日志里面记录的异常
return null;
}
public Set<Object> sMembers( String key) throws Exception {
logger.error("smembersFallBack出现异常进行降级,{}",key); //打印出日志里面记录的异常
return null;
}
public Long sAdd( String key, String member) throws Exception {
logger.error("saddFallBack出现异常进行降级,{},{}",key,member); //打印出日志里面记录的异常
return null;
}
public Long sAdd(String key, String[] members) throws Exception {
logger.error("saddsFallBack出现异常进行降级,{},{}",key,members); //打印出日志里面记录的异常
return null;
}
public Long sRemove( String key, String member) throws Exception {
logger.error("sremoveFallBack出现异常进行降级,{},{}",key,member); //打印出日志里面记录的异常
return null;
}
public boolean hSet( String key, String field, String value) throws Exception {
logger.error("hsetFallBack出现异常进行降级,{},{},{}",key,field,value); //打印出日志里面记录的异常
return false;
}
public String hGet( String key, String field) throws Exception {
logger.error("hgetFallBack出现异常进行降级,{},{}",key,field); //打印出日志里面记录的异常
return null;
}
public Map<Object, Object> hGetAll( String key) throws Exception {
logger.error("hgetallFallBack出现异常进行降级,{}",key); //打印出日志里面记录的异常
return null;
}
public boolean hMSet( String key, Map<Object, Object> values) throws Exception {
logger.error("hmsetFallBack出现异常进行降级,{},{}",key,values); //打印出日志里面记录的异常
return false;
}
public Set<String> findKeyByPartten( String partten) throws Exception {
logger.error("findkeybyparttenFallBack出现异常进行降级,{}",partten); //打印出日志里面记录的异常
return null;
}
public Long getAutoIncrementId( String key, long delta) throws Exception {
logger.error("getautoincrementIdFallBack出现异常进行降级,{},{}",key,delta); //打印出日志里面记录的异常
return null;
}
public Long hIncrementId( String key, String field, long delta) throws Exception {
logger.error("hincrementidFallBack出现异常进行降级,{},{},{}",key,field,delta); //打印出日志里面记录的异常
return null;
}
public boolean setNx( String key, String value, long expireTime) throws Exception {
logger.error("setnxFallBack出现异常进行降级,{},{},{}",key,value,expireTime); //打印出日志里面记录的异常
return false;
}
public boolean hMSet( String key, Object values) throws Exception {
logger.error("hmsetFallBack出现异常进行降级,{},{}",key,values); //打印出日志里面记录的异常
return false;
}
}
最后，对于在模块里面添加缓存机制的逻辑是
1、编写pom文件，添加相应的依赖
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-zuul</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<!--请求缓存-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--cache-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
<dependency>
<groupId>com.qianfeng</groupId>
<artifactId>openapi-commons</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
</dependencies>2、编写application.yml文件，开启降级以及hystrix的相关配置
server:
port: 31100
spring:
application:
name: openapi-gateway
eureka:
client:
service-url:
defaultZone: http://localhost:20000/eureka #我们的注册中心的zone地址
instance:
prefer-ip-address: true
management:
endpoints:
web:
exposure:
include: '*' #所有的监控管理地址
zuul:
ignored-service: '*' #拦截所有的服务,不带代理列表中显示，那么不能发起请求，需要手动添加服务
routes:
openapi-cache: '/*' #配置所有的服务都转发到openapi-cache缓存服务中，目的是使得我们的zuul可以使用，但是实际开发中我们不会将请求转存到缓存，可以写一个没有任何功能的测试服务来进行代理
feign:
hystrix:
enabled: true #开启降级
ribbon:
ConnectTimeOut: 2000
ReadTimeOut: 5000
hystrix:
shareSecurityContext: true #上下文分享
command:
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 5000
3、编写CacheService
package com.zgz.openplatform.gateway.feign;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.*;
import java.util.Map;
import java.util.Set;
/**
* 这个是我们用于方位缓存微服务的feign客户端,这里面主要写的都是我们想要访问的缓存的对应的地址以及参数
*/
@FeignClient(value ="OPENAPI-CACHE" ,fallback = CacheServiceFallback.class)
public interface CacheService {
@PostMapping("/cache/set/{key}/{value}/{expireTime}")
boolean save2Redis(@PathVariable String key, @PathVariable String value, @PathVariable long expireTime) throws Exception ;
@GetMapping("/cache/get/{key}")
String getFromRedis(@PathVariable String key) throws Exception;
@PostMapping("/cache/delete/{key}")
boolean deleteKey(@PathVariable String key) throws Exception ;
@PostMapping("/cache/expire/{key}/{expireTime}")
boolean expire(@PathVariable String key, @PathVariable long expireTime) throws Exception;
@GetMapping("/cache/getid/{key}")
Long getAutoIncrementId(@PathVariable String key) throws Exception;
@GetMapping("/cache/smembers/{key}")
Set<Object> sMembers(@PathVariable String key) throws Exception ;
@PostMapping("/cache/sadd/{key}/{member}")
Long sAdd(@PathVariable String key, @PathVariable String member) throws Exception ;
@PostMapping("/cache/sadds/{key}")
Long sAdd(@PathVariable String key, @RequestParam("members") String[] members) throws Exception;
@PostMapping("/cache/sremove/{key}/{member}")
Long sRemove(@PathVariable String key, @PathVariable String member) throws Exception ;
@PostMapping("/cache/hset/{key}/{field}/{value}")
boolean hSet(@PathVariable String key, @PathVariable String field, @PathVariable String value) throws Exception ;
@GetMapping("/cache/hget/{key}/{field}")
String hGet(@PathVariable String key, @PathVariable String field) throws Exception;
@GetMapping("/cache/hgetall/{key}")
Map<Object, Object> hGetAll(@PathVariable String key) throws Exception;
@PostMapping("/cache/hmset/{key}")
boolean hMSet(@PathVariable String key, @RequestBody Map<Object, Object> values) throws Exception ;
@GetMapping("/cache/keys/{partten}")
Set<String> findKeyByPartten(@PathVariable String partten) throws Exception ;
@GetMapping("/cache/increment/{key}/{delta}")
Long getAutoIncrementId(@PathVariable String key, @PathVariable long delta) throws Exception;
@GetMapping("/cache/hIncrementid/{key}/{field}/{delta}")
Long hIncrementId(@PathVariable String key, @PathVariable String field, @PathVariable long delta) throws Exception;
@PostMapping("/cache/setnx/{key}/{value}/{expireTime}")
boolean setNx(@PathVariable String key, @PathVariable String value, @PathVariable long expireTime) throws Exception;
/**
* 这个方法和上面的hMSet是一样的作用,都是将参数转成json写出去
* @param key
* @param value
* @return
* @throws Exception
*/
@PostMapping("/cache/hmset/{key}")
boolean hMSet(@PathVariable String key, @RequestBody Object value) throws Exception ;
}
4、编写相应的fallback文件
package com.zgz.openplatform.gateway.feign;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.*;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
/**
* feign的降级机制，具体实现要一个一个填写
*/
@Component
public class CacheServiceFallback implements CacheService{
//日志在logback-spring.xml里面写好了，这里调用一下
private static Logger logger = LoggerFactory.getLogger(CacheServiceFallback.class);
/**
* 保存数据到缓存中的降级方法
* @param key
* @param value
* @param expireTime
* @return
* @throws Exception
*/
public boolean save2Redis( String key, String value, long expireTime) throws Exception {
logger.error("save2Redis出现异常进行降级,{},{}",key,value); //打印出日志里面记录的异常
return false;
}
public String getFromRedis( String key) throws Exception {
logger.error("getFromRedis出现异常进行降级,{}",key);
return null;
}
public boolean deleteKey( String key) throws Exception {
logger.error("save2Redis出现异常进行降级,{}",key); //打印出日志里面记录的异常
return false;
}
public boolean expire( String key, long expireTime) throws Exception {
logger.error("save2Redis出现异常进行降级,{}",key); //打印出日志里面记录的异常
return false;
}
public Long getAutoIncrementId( String key) throws Exception {
logger.error("getautoincrementidFallBack出现异常进行降级,{}",key); //打印出日志里面记录的异常
return null;
}
public Set<Object> sMembers( String key) throws Exception {
logger.error("smembersFallBack出现异常进行降级,{}",key); //打印出日志里面记录的异常
return null;
}
public Long sAdd( String key, String member) throws Exception {
logger.error("saddFallBack出现异常进行降级,{},{}",key,member); //打印出日志里面记录的异常
return null;
}
public Long sAdd(String key, String[] members) throws Exception {
logger.error("saddsFallBack出现异常进行降级,{},{}",key,members); //打印出日志里面记录的异常
return null;
}
public Long sRemove( String key, String member) throws Exception {
logger.error("sremoveFallBack出现异常进行降级,{},{}",key,member); //打印出日志里面记录的异常
return null;
}
public boolean hSet( String key, String field, String value) throws Exception {
logger.error("hsetFallBack出现异常进行降级,{},{},{}",key,field,value); //打印出日志里面记录的异常
return false;
}
public String hGet( String key, String field) throws Exception {
logger.error("hgetFallBack出现异常进行降级,{},{}",key,field); //打印出日志里面记录的异常
return null;
}
public Map<Object, Object> hGetAll( String key) throws Exception {
logger.error("hgetallFallBack出现异常进行降级,{}",key); //打印出日志里面记录的异常
return null;
}
public boolean hMSet( String key, Map<Object, Object> values) throws Exception {
logger.error("hmsetFallBack出现异常进行降级,{},{}",key,values); //打印出日志里面记录的异常
return false;
}
public Set<String> findKeyByPartten( String partten) throws Exception {
logger.error("findkeybyparttenFallBack出现异常进行降级,{}",partten); //打印出日志里面记录的异常
return null;
}
public Long getAutoIncrementId( String key, long delta) throws Exception {
logger.error("getautoincrementIdFallBack出现异常进行降级,{},{}",key,delta); //打印出日志里面记录的异常
return null;
}
public Long hIncrementId( String key, String field, long delta) throws Exception {
logger.error("hincrementidFallBack出现异常进行降级,{},{},{}",key,field,delta); //打印出日志里面记录的异常
return null;
}
public boolean setNx( String key, String value, long expireTime) throws Exception {
logger.error("setnxFallBack出现异常进行降级,{},{},{}",key,value,expireTime); //打印出日志里面记录的异常
return false;
}
public boolean hMSet( String key, Object values) throws Exception {
logger.error("hmsetFallBack出现异常进行降级,{},{}",key,values); //打印出日志里面记录的异常
return false;
}
}
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