commonsql.java

这是我们几个人在培训过程中做的第一个 小项目 仅供参考

package com.t2.myblog.dao;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class CommonSql {
	Connection conn = null;
	PreparedStatement ps=null;
	ResultSet rs=null;

	public boolean openConnect() {
		boolean flag = false;
		// 读取配置文件
		Properties properties = new Properties();
		// 虚拟路径转为物理路径
		String filename = "C:\\Java\\Apache Tomcat 6.0.16\\webapps\\MyBlog\\db.properties";
		FileInputStream inputstream;
		try {
			inputstream = new FileInputStream(filename);
			properties.load(inputstream);
			String strclass = properties.getProperty("class");
			String strurl = properties.getProperty("url");
			String struser = properties.getProperty("user");
			String strpwd = properties.getProperty("pwd");
			inputstream.close();
			Class.forName(strclass);
			conn = DriverManager.getConnection(strurl, struser,
					strpwd);
			flag = true;
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return flag;
	}
    /**
     * insert update delete
     * @param sql
     * @return boolean
     */
	public boolean execUpdate(String sql) {
		boolean flag = false;
		if (openConnect()) {
			try {
				ps = conn.prepareStatement(sql);
				ps.executeUpdate();
				ps.close();
				conn.close();
				flag=true;
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return flag;
	}
	/**
	 * select
	 * @param sql
	 * @return ResultSet
	 */
	public ResultSet execQuery(String sql) {
		rs = null;
		if (openConnect()) {
			try {
				ps = conn.prepareStatement(sql);
				rs=ps.executeQuery();
								
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return rs;
	}
	
	public void closeAll(){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(ps!=null){
			try {
				ps.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
}