缓存对减轻服务器压力相当重要，这一篇简单记录一下。

缓存这一块，主要用到了这4个注解：@EnableCaching， @Cacheable，@CachePut，@CacheEvict 。 其中@EnableCaching告诉Spring框架开启缓存能力，@Cacheable来配置访问路径是否缓存，@CachePut来更新缓存，@CacheEvict来清理缓存，具体用法看下面的代码。 1.开启Spring的缓存功能

import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cache.annotation.EnableCaching;@SpringBootApplication@EnableCaching//开启缓存public class Application {    public static void main(String[] args) {        SpringApplication.run(Application.class, args);    }}

2.对访问路径（URL）配置缓存信息

@GetMapping("/{id}")    @Cacheable("users")//设置缓存用户信息，缓存的名称为users    public User getUserInfo(@PathVariable int id) {        User user = new User();        user.setId(id);        int random=new Random().nextInt(999);        user.setName("user " + random);        System.out.println("random is "+random);        return user;    }

3.更新缓存信息

@PostMapping("/update")    @CachePut(value ="users",key = "#user.getId()")//更新指定的用户缓存信息    public boolean updateUserInfo( User user){        System.out.println("updateUserInfo "+user.toString());        return true;    }

4.清除缓存信息

@PostMapping("/remove")    @CacheEvict(value = "users",key = "#user.getId()")//清除指定的用户缓存信息    public boolean removeUserInfoCache(@RequestBody User user){        System.out.println("removeUserInfoCache "+user.toString());        return true;    }    @PostMapping("/remove/all")    @CacheEvict(value = "users",allEntries = true)//清除所有的用户缓存信息    public boolean removeAllUserInfoCache(){        System.out.println("removeAllUserInfoCache ");        return true;    }

下面放一个完整的缓存类demo

package com.spring.cache;import com.spring.beans.User;import org.springframework.cache.annotation.CacheEvict;import org.springframework.cache.annotation.CachePut;import org.springframework.cache.annotation.Cacheable;import org.springframework.web.bind.annotation.*;import java.util.Random;/** * Created by zhangyi on 2017/4/13. * * 缓存demo * */@RestController@RequestMapping("/cache/user")public class CacheController {    @GetMapping("/{id}")    @Cacheable("users")//设置缓存用户信息，缓存的名称为users    public User getUserInfo(@PathVariable int id) {        User user = new User();        user.setId(id);        int random=new Random().nextInt(999);        user.setName("user " + random);        System.out.println("random is "+random);        return user;    }    @PostMapping("/update")    @CachePut(value ="users",key = "#user.getId()")//更新指定的用户缓存信息    public boolean updateUserInfo( User user){        System.out.println("updateUserInfo "+user.toString());        return true;    }    @PostMapping("/remove")    @CacheEvict(value = "users",key = "#user.getId()")//清除指定的用户缓存信息    public boolean removeUserInfoCache(@RequestBody User user){        System.out.println("removeUserInfoCache "+user.toString());        return true;    }    @PostMapping("/remove/all")    @CacheEvict(value = "users",allEntries = true)//清除所有的用户缓存信息    public boolean removeAllUserInfoCache(){        System.out.println("removeAllUserInfoCache ");        return true;    }}