版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/qq_41690324/article/details/82849798
package JDBCUtil;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;
/*
* 编写JDBC的工具类,获取数据库的连接
* 采用读取配置文件的方式
* 读取配置文件与获取连接,最好只执行一次,所以采用static{}
*/
public class JDBCUtilConfig {
private static Connection con;
private static String driverClass;
private static String url;
private static String username;
private static String password;
static {
try {
readConfig();
Class.forName(driverClass);
con = DriverManager.getConnection(url, username, password);
} catch (Exception e) {
throw new RuntimeException("数据库连接失败");
}
}
private static void readConfig() throws IOException {
InputStream in = JDBCUtilConfig.class.getClassLoader()
.getResourceAsStream("database.properties");
Properties pro = new Properties();
pro.load(in);
driverClass = pro.getProperty("driverClass");
url = pro.getProperty("url");
username = pro.getProperty("username");
password = pro.getProperty("password");
}
public static Connection getConnection() {
return con;
}
}
使用了工具类之后原来的大量代码只有一行.
package demo5;
import java.sql.Connection;
import JDBCUtil.JDBCUtilConfig;
public class JDBCUtilConfigTest {
public static void main(String[] args) {
Connection con = JDBCUtilConfig.getConnection();
System.out.println(con);
}
}