java--jdbc连接mysql驱动

jdbc的使用步骤

1、加载驱动类

2、建立连接

3、执行SQL

4、遍历结果集

5、释放连接

以下代码均为自习练习，连接自己的数据库，对表进行简单的查询，删除操作，其中还有PreparedStatement的一个小练习。代码如下：

@Test
public void testPreparedDelete(){

/*
* 写的不是太规范，没有关闭资源
*/
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection(
"jdbc:mysql://localhost:3306/hibernate3","root","123");
String sql="delete from STUDENTS where STUDENT_ID=?";
PreparedStatement ps=conn.prepareStatement(sql);

ps.setInt(1, 3);
int num=ps.executeUpdate();

System.out.println(num);
} catch (Exception e) {
}
}

@Test
public void testNormalDelete(){

Connection conn=null;
java.sql.Statement stmt=null;

try {
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/hibernate3","root","123");
stmt=conn.createStatement();

String sql="delete from students where student_id=3";

int num=stmt.executeUpdate(sql);
if(num>0){
System.out.println("删除成功");
}else{
System.out.println("error");
}


} catch (Exception e) {
e.printStackTrace();
}



}

@Test
public void testNormalSelect(){

Connection conn=null;
Statement stmt=null;
ResultSet rs=null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection(
"jdbc:mysql://127.0.0.1:3306/hibernate3","root","123");

String sql="select * from students";
stmt=(Statement) conn.createStatement();

rs=stmt.executeQuery(sql);
while(rs.next()){
String name=rs.getString("STUDENT_NAME");
int age=rs.getInt("STUDENT_AGE");
int id=rs.getInt("STUDENT_ID");

System.out.println("id="+id+",name="+name+",age="+age);


}

} catch (Exception e) {
e.printStackTrace();
}finally{

try {
if(conn!=null){
conn.close();
}

if(stmt!=null){
stmt.close();
}

if(rs!=null){
rs.close();
}

} catch (Exception e2) {
// TODO: handle exception
}
}

}