package util;
import java.io.InputStream;
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 JdbcUtil {
//连接数据库的四要素
private static Properties p=new Properties();
static { //当JdbcUtil这份字节码被加载进JVM就立刻执行
try {
//加载和读取db.properties文件
InputStream instream=Thread.currentThread().getContextClassLoader().getResourceAsStream("db.properties");
p.load(instream);//加载
//--------------------------------------
Class.forName(p.getProperty("driverClassName"));
}catch(Exception e) {
e.printStackTrace();
}
}
//创建并返回一个Connection对象
public static Connection getConn() {
try {
return DriverManager.getConnection(p.getProperty("url"),
p.getProperty("username"),
p.getProperty("password"));
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
//释放资源
public static void close(ResultSet rs,PreparedStatement pst,Connection conn){
try {
if(rs!=null) {
rs.close();
}
}catch(Exception e) {
}finally {
try {
if(pst!=null) {
pst.close();
}
}catch(Exception e) {
e.printStackTrace();
}finally {
try {
if(conn!=null) {
conn.close();
}
}catch(Exception e) {
e.printStackTrace();
}
}
}
}
}
