//配置文件：config.properties放在classpath下
jdbc_driver=com.mysql.jdbc.Driver
jdbc_username=root
jdbc_password=
jdbc_url=jdbc\:mysql\://localhost\:3306/student?useUnicode\=true&characterEncoding\=utf-8
//读取properties文件的工具类
package com.util;

import java.io.IOException;
import java.util.Properties;

public class ProMgr {

	private static Properties props = new Properties();

	static {
		try {
			props.load(ProMgr.class.getClassLoader().getResourceAsStream(
					"config.properties"));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	private ProMgr() {
	}

	public static String getProperty(String key) {
		return props.getProperty(key);
	}

}
//数据库连接类：
package com.jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import com.util.ProMgr;

public class DBC {
	// private static final String DBDRIVER="oracle.jdbc.driver.OracleDriver";
	// private static final String USERNAME="scott";
	// private static final String PASSWORD ="tiger";
	// private static final String
	// URL="jdbc:oracle:thin@localhost:1521:student";

	// private static final String DBDRIVER = "com.mysql.jdbc.Driver";
	// private static final String USERNAME = "root";
	// private static final String PASSWORD = "";
	// private static final String URL =
	// "jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf-8";

	private static final String DBDRIVER = ProMgr.getProperty("jdbc_driver");
	private static final String USERNAME = ProMgr.getProperty("jdbc_username");
	private static final String PASSWORD = ProMgr.getProperty("jdbc_password");
	private static final String URL = ProMgr.getProperty("jdbc_url");
	private Connection conn;

	public DBC() {
		try {
			Class.forName(DBDRIVER);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

	public Connection conn() {
		try {
			conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}

	public void close() {
		if (conn != null) {
			try {
				conn.close();
				conn = null;
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

}
//测试类：
package com.jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import com.util.ProMgr;

public class DBC {
	// private static final String DBDRIVER="oracle.jdbc.driver.OracleDriver";
	// private static final String USERNAME="scott";
	// private static final String PASSWORD ="tiger";
	// private static final String
	// URL="jdbc:oracle:thin@localhost:1521:student";

	// private static final String DBDRIVER = "com.mysql.jdbc.Driver";
	// private static final String USERNAME = "root";
	// private static final String PASSWORD = "";
	// private static final String URL =
	// "jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf-8";

	private static final String DBDRIVER = ProMgr.getProperty("jdbc_driver");
	private static final String USERNAME = ProMgr.getProperty("jdbc_username");
	private static final String PASSWORD = ProMgr.getProperty("jdbc_password");
	private static final String URL = ProMgr.getProperty("jdbc_url");
	private Connection conn;

	public DBC() {
		try {
			Class.forName(DBDRIVER);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

	public Connection conn() {
		try {
			conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}

	public void close() {
		if (conn != null) {
			try {
				conn.close();
				conn = null;
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

}

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