一、状态模式
二、策略模式
1. JDBC案列查询
接口
- 接口负责数据的转换，具体怎么转换，需要开发者自己实现；
package com.day.dreamer.thread.day01;
import java.sql.ResultSet;
/**
* @author EShu
*/
public interface IHandleResult<T> {
/**
* 1. 使用范形，保证返回的值为任意类型
* 具体是什么样子，自己去手动实现
*/
T handle(ResultSet resultSet);
}
查询数据类
- 调用该类时候，只需要自己实现对应的处理结果的类，就可以实现对不同数据库的查询的结果的处理；
- 每个类功能单一，职责分明；
package com.day.dreamer.thread.day01;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* @author EShu
*/
public class GetResult {
private Connection connection;
public GetResult(Connection connection) {
this.connection = connection;
}
public <T> T getResult(IHandleResult<T> iHandleResult, String sql) throws SQLException {
// 1. 只负责查询结果
PreparedStatement statement = connection.prepareStatement(sql);
ResultSet resultSet = statement.executeQuery();
T handle = iHandleResult.handle(resultSet);
return handle;
}
}
2. Runnable接口和Thread 类
Runnable接口
@FunctionalInterface
public interface Runnable {
/**
* When an object implementing interface <code>Runnable</code> is used
* to create a thread, starting the thread causes the object's
* <code>run</code> method to be called in that separately executing
* thread.
* <p>
* The general contract of the method <code>run</code> is that it may
* take any action whatsoever.
*
* @see java.lang.Thread#run()
*/
public abstract void run();
}
Thread 类
public class Thread implements Runnable {
/* What will be run. */
private Runnable target;
public Thread(Runnable target) {
this(null, target, "Thread-" + nextThreadNum(), 0);
}
@Override
public void run() {
if (target != null) {
target.run();
}
}
}
