Spring Cache与JPA的简单使用

@Cacheable

不能使用result 原因：运行前就需要key

可写SpEL表达式

@Caching：定义复杂的缓存规则

如：

@Caching(
cacheable = {
@Cacheable(value = "user", key = "#id")
},
put = {
@Cacheput(value = "user", key = "#result.id"),
@CachePut(value = "user", key = "#result.username")
}
)

@Cacheconfig

抽取公共的cache属性
• cacheNames 也就是 value
• cacheResolver
• keyGenerator
• cacheManager

开启基于注解缓存

• 启动类加上 @EnableCaching

package com.live;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

@SpringBootApplication
@EnableCaching
public class CacheApplication {

public static void main(String[] args) {
SpringApplication.run(CacheApplication.class, args);
}

}

Model

package com.live.model;

import lombok.Data;
import javax.persistence.*;

@Entity
@Data
@Table(name = "cache_user")
public class CacheUser {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;

@Column(name = "cache_username", length = 100, unique = true)
private String username;

@Column(name = "cache_password", length = 125)
private String password;

}

Repository

package com.live.repository;

import com.live.model.CacheUser;
import org.springframework.data.jpa.repository.JpaRepository;

public interface CacheUserRepository extends JpaRepository<CacheUser, Integer> {

CacheUser findByUsername(String username);

CacheUser findOneById(Integer id);

}

Controller

package com.live.controller;

import com.live.model.CacheUser;
import com.live.repository.CacheUserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@CacheConfig(cacheNames = "user")
public class CacheUserController {

@Autowired
private CacheUserRepository cacheUserRepository;

@GetMapping("/findOne/{id}")
@Cacheable(key = "#id")
public CacheUser findByName(@PathVariable(value = "id") Integer id) {
System.out.println("查询ID：" + id);
return cacheUserRepository.findOneById(id);
}

@GetMapping("/findOneByName/{name}")
@Cacheable(keyGenerator = "myKeyGenerator")
public CacheUser findByName(@PathVariable(value = "name") String name) {
System.out.println("查询Name：" + name);
return cacheUserRepository.findByUsername(name);
}

@GetMapping("/findAll")
@Cacheable(keyGenerator = "myKeyGenerator")
public List<CacheUser> findAll() {
return cacheUserRepository.findAll();
}

@GetMapping("/update/{id}/{username}")
@CachePut(key = "#id")
public CacheUser updateById(@PathVariable(value = "username") String username, @PathVariable(value = "id") Integer id) {
CacheUser update = cacheUserRepository.findOneById(id);
update.setUsername(username);
return cacheUserRepository.save(update);
}

@GetMapping("/clearCacheAll")
@CacheEvict(allEntries = true)
public String clearCacheAll() {
return "SUCCESS!";
}

@GetMapping("/clearCacheById/{id}")
@CacheEvict(key = "#id")
public String clearCacheById(@PathVariable(value = "id") Integer id) {
return "SUCCESS!";
}

}

自定义KeyGenerator

package com.live.config;

import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Arrays;
import java.util.List;

@Configuration
public class MyCacheKeyGenerator {

@Bean(name = "myKeyGenerator")
public KeyGenerator keyGenerator() {
return (o, method, objects) -> {
String key;
List<Object> args = Arrays.asList(objects);
if (args.size() > 0) {
key = method.getName() + "_" + args;
} else {
key = method.getName();
}
System.out.println(s);
return key;
};
}

}