1 类继承的方法来实现请求缓存

1.1 编写CacheCommand类

package com.study.service.hystrix;import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandKey;
import com.netflix.hystrix.HystrixRequestCache;
import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategyDefault;
import org.springframework.web.client.RestTemplate;public class CacheCommand extends HystrixCommand<String> {private Long cacheKey;private RestTemplate restTemplate;private Integer uid;public CacheCommand(Long cacheKey, RestTemplate restTemplate, Integer uid) {super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("cache-group")).andCommandKey(HystrixCommandKey.Factory.asKey("cache-test")));this.restTemplate = restTemplate;this.uid = uid;this.cacheKey = cacheKey;}@Overrideprotected String run() throws Exception {System.out.println("没有缓存，查询数据~！");String url = "http://study-user/user/{id}";String info = restTemplate.getForObject(url, String.class, uid);return info;}@Overrideprotected String getCacheKey() {return String.valueOf(cacheKey);}//清空缓存public void clearRequestCache(){HystrixRequestCache.getInstance(HystrixCommandKey.Factory.asKey("cache-test"), HystrixConcurrencyStrategyDefault.getInstance()).clear(String.valueOf(cacheKey));}
}

1.2 在OrderService中添加getUser2方法

    // 继承类的方式public String getUser2(Integer id) {Long cacheKey = 9999L;CacheCommand cacheCommand = new CacheCommand(9999L, restTemplate, id);String val = cacheCommand.execute();return val;}

1.3 在OrderContoller中编写测试接口

    @RequestMapping("/cache")public String cache() {HystrixRequestContext context = HystrixRequestContext.initializeContext();// 调用用户，查询用户信息，String result1 = orderService.getUser2(1);String result2 = orderService.getUser2(2);context.close();return "result1：" + result1 + "，result2：" + result2;}

访问接口测试，可以发现，在cachekey相同的情况下，返回的值是相同的

如果需要不同时，直接修改cachekey可以获取，如：

修改getUser2为

    // 继承类的方式public String getUser2(Integer id) {Long cacheKey = 9999L+id;CacheCommand cacheCommand = new CacheCommand(9999L, restTemplate, id);String val = cacheCommand.execute();return val;}

也可以直接调用清理缓存的方法，如下：

    public String getUser2(Integer id) {Long cacheKey = 9999L;CacheCommand cacheCommand = new CacheCommand(9999L, restTemplate, id);String val = cacheCommand.execute();// 清空request缓存cacheCommand.clearRequestCache();return val;}

2 注解方式实现请求缓存

2.1 在OrderService中添加getUser3方法以及clearRequestCache方法

    //请求缓存注解@CacheResult@HystrixCommand(commandKey = "cache-user")public String getUser3(Integer id, @CacheKey Long cacheKey) {String url = "http://study-user/user/{id}";String info = restTemplate.getForObject(url, String.class, id);return info;}//缓存清除注解@CacheRemove(commandKey = "cache-user")@HystrixCommandpublic void clearRequestCache(@CacheKey Long cacheKey) {}

2.2 在OrderContoller中编写测试接口

    @RequestMapping("/cache2")public String cache2() {HystrixRequestContext context = HystrixRequestContext.initializeContext();// 调用用户，查询用户信息，String result1 = orderService.getUser3(1, 12345L);String result2 = orderService.getUser3(2, 12345L);context.close();return "cache2 result1：" + result1 + "， cache2 result2：" + result2;}

如果要清除缓存，直接调用clearRequestCache方法。