SpringBoot入门之缓存

缓存对减轻服务器压力至关重要，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)//清除全部的用户缓存信息
    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)//清除全部的用户缓存信息
    public boolean removeAllUserInfoCache(){
        System.out.println("removeAllUserInfoCache ");
        return true;
    }


}