spring缓存机制-根据condition加入缓存(三)

  在UserServiceImpl代码中通过@Cacheable的condition值设置只有满足某种条件方法的返回值才放入缓存.

<span style="font-size:12px;">package com.ilucky.spring.cache.service.impl;

import java.util.Map;

import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;

import com.ilucky.spring.cache.dao.UserDao;
import com.ilucky.spring.cache.model.User;
import com.ilucky.spring.cache.service.UserService;

/**
 * @author IluckySi
 * @date 20140613
 */
public class UserServiceImpl implements UserService {

	private UserDao userDao;
	
	/**
	 * JVM加载spring配置文件时, 通过set方法注入本类的依赖.
	 * @param userDao
	 */
	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}

	/**
	 * 对数据进行增删改时清空缓存, 查询时使用缓存, 其中value为缓存区,
	 * allEntries表示清空缓存中所有的数据, 使用#"user.id + '方法名'"做为key.
	 */
	@Override
    @CacheEvict(value = "data", key = "#id + 'add'")  
	public void add(User user) {
		System.out.println("UserService: method- add(User user)" );
		userDao.add(user);
	}

	@Override
	@CacheEvict(value = "data", key = "#id + 'delete'")  
	public void delete(String id) {
		System.out.println("UserService: method-delete(String id)" );
		userDao.delete(id);
	}

	@Override
	@CacheEvict(value = "data", key = "#user.id+ 'update'")  
	public void update(User user) {
		System.out.println("UserService: method-update(User user)" );
		userDao.update(user);
	}

	@Override
	@Cacheable(value = "data", condition = "#id.length() > 5")   
	public User find(String id) {
		System.out.println("UserService: method-find(String id)" );
		return userDao.find(id);
	}

	@Override
	@Cacheable(value = "data")  
	public Map<String, User> getAll() {
		System.out.println("UserService: method-getAll()" );
		return userDao.getAll();
	}
}
</span>

4.最后通过测试类测试spring缓存机制是否生效,直接看代码MainTest.

<span style="font-size:12px;">package com.ilucky.spring.cache;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.ilucky.spring.cache.model.User;
import com.ilucky.spring.cache.service.UserService;

/**
 * @author IluckySi
 * @date 20140613
 * 测试spring缓存机制是否生效.
 */
public class MainTest {

	public static void main(String[] args) {
		
		//加载ClassPath路径下的spring配置文件, 并获取service bean.
		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring-cache.xml");  
		UserService userService = context.getBean("userService", UserService.class); 
		System.out.println("service bean: " + userService);
		
		//添加两个用户.
		userService.add(new User("1", "Ilucky1", "pwd1"));
		userService.add(new User("2222222", "Ilucky2", "pwd2"));
		
		//验证#id.length <= 5是否被缓存.
		User user1 = userService.find("1");
		System.out.println(user1);
		User user11 = userService.find("1");
		System.out.println(user11);
		
		//验证#id.length > 5是否被缓存.
		User user2 = userService.find("2222222");
		System.out.println(user2);
		User user22= userService.find("2222222");
		System.out.println(user22);
	}
}
/**
spring缓存分为两种:方法和数据,如果方法被清除了,需要重新从数据库获取数据放入缓存,另外只有方法加入了缓存才可以获取缓存中的数据.
输出结果:
service bean: com.ilucky.spring.cache.service.impl.UserServiceImpl@15e2075
UserService: method- add(User user)
UserDao method- add(User user)
UserService: method- add(User user)
UserDao method- add(User user)
UserService: method-find(String id)
UserDao method- find(String id)
1-Ilucky1-pwd1
UserService: method-find(String id)
UserDao method- find(String id)
1-Ilucky1-pwd1
UserService: method-find(String id)
UserDao method- find(String id)
2222222-Ilucky2-pwd2
2222222-Ilucky2-pwd2
*/
</span>