MyBatis （六）结合多线程实现模拟缓存

左手的ㄟ右手 2022-05-27 11:07 123阅读 0赞

**模拟多线程实现一级缓存**

设置两个线程，均用于实现查询功能，一级缓存默认打开，不打开二级缓存

package test;
    
    import java.io.InputStream;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.apache.ibatis.session.SqlSessionManager;
    
    import mapper.AuthorMapper;
    import po.Author;
    
    /**
     * 结合多线程实现模拟一级缓存
     * 设置了两个线程，两个线程均用于查询，查询的是不同的内容
     * @author baka
     */
    public class test1{
    	private static SqlSession session;
    
    	public static SqlSession getSqlSessionTest() {
    		if (session == null) {
    			String resource = "SqlMapperConfig.xml";
    			InputStream iStream = test1.class.getClassLoader().getResourceAsStream(resource);
    			SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(iStream);
    			session = factory.openSession();
    		}
    		return session;
    	}
    
    	//从线程
    	static class Run implements Runnable{
    		@Override
    		public void run() {
    			try {
    				//获取到操作author表的映射类
    				AuthorMapper authorMapper = getSqlSessionTest().getMapper(AuthorMapper.class);  
    				Author author = authorMapper.selectByPrimaryKey(1);
    				System.out.println("-----------------------------------------------");
    				System.out.println("从线程：" + author.toString());
    				Thread.sleep(10);
    			} catch (InterruptedException e) {
    				e.printStackTrace();
    			}
    		}
    	}
    
    	//主线程
    	public static void main(String[] args) throws InterruptedException {
    		Run run = new Run();
    		for (int i = 0; i < 10; i++) {
    			Thread thread = new Thread(run);
    			//获取到操作author表的映射类
    			AuthorMapper authorMapper = getSqlSessionTest().getMapper(AuthorMapper.class);  
    			Author author1 = new Author(1, "baka", i+"123", null, null);
    			authorMapper.updateByPrimaryKey(author1);
    			session.commit();
    			Author author = authorMapper.selectByPrimaryKey(2);
    			System.out.println("-----------------------------------------------");
    			System.out.println("主线程：" + author.toString());
    			thread.sleep(10);
    			thread.start();
    		}
    	}
    }

**模拟多线程实现二级缓存**

设置两个线程，均用于实现查询功能，打开二级缓存

注意，查询之后一定要将一级缓存刷入至二级缓存，不然命中率将为0

package test;
    
    import java.io.InputStream;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.apache.ibatis.session.SqlSessionManager;
    
    import mapper.AuthorMapper;
    import po.Author;
    
    /**
     * 结合多线程实现模拟二级缓存，设置了两个线程，
     * 两个线程均用于查询
     * @author baka
     */
    public class test2 {
    	private static String resource = "SqlMapperConfig.xml";
    	private static InputStream iStream = test1.class.getClassLoader().getResourceAsStream(resource);
    	private static SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(iStream);
    
    	// 从线程
    	static class Run implements Runnable {
    		@Override
    		public void run() {
    			try {
    				SqlSession session = factory.openSession();
    				AuthorMapper authorMapper = session.getMapper(AuthorMapper.class);
    				Author author = authorMapper.selectByPrimaryKey(1);
    				session.close();  //一级缓存刷入二级缓存
    				System.out.println("从线程：" + author.toString());
    				Thread.sleep(10);
    			} catch (InterruptedException e) {
    				e.printStackTrace();
    			}
    			System.out.println("--------------------------------------");
    		}
    	}
    
    	// 主线程
    	public static void main(String[] args) throws InterruptedException {
    		Run run = new Run();
    		for (int i = 0; i < 10; i++) {
    			Thread thread = new Thread(run);
    			SqlSession session = factory.openSession();
    			AuthorMapper authorMapper = session.getMapper(AuthorMapper.class);
    			Author author = authorMapper.selectByPrimaryKey(2);
    			session.close();   //一级缓存刷入二级缓存
    			System.out.println("主线程：" + author.toString());
    			thread.sleep(10);
    			thread.start();
    			System.out.println("--------------------------------------");
    		}
    	}
    }