最基础的java JDBC连接数据库代码并关闭连接

class Testone{

// 加载驱动

Connection conn = null;

PreparedStatement ps = null;

ResultSet rs = null;

try {

Class.forName("com.mysql.jdbc.Driver");

String url="jdbc:mysql://localhost:3306/test";

//获得连接Connection

try {

conn =DriverManager.getConnection(url,"root","123");

//Statement stat =conn.createStatement();

//ResultSet rs=stat.executeQuery("select username from user");

String sql="select password from user where username=?";

String [] str={"lfxa"};

ps=conn.prepareStatement(sql);

ps.setString(1, "xiner");

rs=ps.executeQuery();

while(rs.next()){

System.out.println("------>"+rs.getString(1));

System.out.println("------>"+rs.getString("password"));

}

} catch (Exception e) {

e.printStackTrace();

}finally{

if(rs != null){

try{

rs.close();

rs = null;

}catch(Exception e){

e.printStackTrace();

}finally{

if(ps != null){

try{

ps.close();

ps = null;

}catch(Exception e){

e.printStackTrace();

}finally{

if(conn != null){

try{

conn.close();

conn = null;

}catch(Exception e){

e.printStackTrace();

}

}

}

}

}

}

}

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

}