package demo1;
import java.sql.Connection;
import java.sql.DriverManager;
public class JDBCutilDemo {
private static final String DRIVERNAME = "com.mysql.jdbc.Driver";
private static final String URL = "jdbc:mysql://localhost:3306/day29";
private static final String USERNAME = "root";
private static final String PASSWORD = "Aa123456";
static {
//静态代码块中的代码在使用类的时候就会调用
try {
//注册驱动
Class.forName(DRIVERNAME);
} catch (ClassNotFoundException e) {
System.out.println("注册驱动失败!");
}
}
public static Connection getConn() throws Exception {
/*
* 返回数据库链接
*/
Connection conn = DriverManager.getConnection(URL,USERNAME,PASSWORD);
return conn;
}
}
package demo1;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;
public class JDBCutilDemo1 {
private static String DRIVERNAME;
private static String URL;
private static String USERNAME;
private static String PASSWORD;
static {
//从properties中获得配置参数
try {
getConfig();
} catch (Exception e) {
e.printStackTrace();
}
//静态代码块中的代码在使用类的时候就会调用
try {
//注册驱动
Class.forName(DRIVERNAME);
} catch (ClassNotFoundException e) {
System.out.println("注册驱动失败!");
}
}
public static Connection getConn() throws Exception {
/*
* 返回数据库链接
*/
Connection conn = DriverManager.getConnection(URL,USERNAME,PASSWORD);
return conn;
}
private static void getConfig() throws Exception {
//用类名.class.getClassLoader().getResourceAsStream(文件名);来获得bin目录下的指定文件输入流
//在eclipse中将properties新建到src中会自动复制到bin目录,这样在交付软件的时候就不用在手动复制配置文件或修改代码了
InputStream in = JDBCutilDemo1.class.getClassLoader().getResourceAsStream("db.properties");
Properties pro = new Properties();
pro.load(in);
DRIVERNAME = pro.getProperty("drivername");
URL = pro.getProperty("url");
USERNAME = pro.getProperty("username");
PASSWORD = pro.getProperty("password");
System.out.println("--------测试数据---------");
System.out.println(DRIVERNAME);
System.out.println(URL);
System.out.println(USERNAME);
System.out.println(PASSWORD);
}
}
package demo1;
import java.sql.Connection;
public class Test1 {
public static void main(String[] args) throws Exception {
// Connection conn = JDBCutilDemo.getConn();
Connection conn = JDBCutilDemo1.getConn();
System.out.println(conn);
}
}