初学JDBC，JDBC工具类的简单封装
//工具类不需要被继承
public final class JdbcUtils{
//封装数据库连接参数，便于后期更改参数值
private static String url="jdbc:mysql://localhost:3306/jdbc";
private static String user="userName";
private static String password="password";
//无需被创建对象
private JdbcUtils(){}
//静态代码块：在项目启动时候执行
static{
try{
Class.forName("com.mysql.jdbc.Driver");
}catch(ClassNotFoundException e){
throw new IninitializerError(e);
}
}
//创建数据库连接
public static Connection getConnetcion() throws SQLException{
return DrivaerManager.getConnetcion(url,user,password);
}
//释放资源
public static void freeResource(ResultSet resultSet,Statement statement,Connection conn){
try{
if(resultSet!=null)
resultSet.close();
}catch(SQLException e){
e.printStackTrace();
}finally{
try{
if(statement!=null)
statement.close();
}catch(SQLException e){
e.printStackTrace();
}finally{
try{
if(conn!=null)
conn.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
}
}
//示例
public class UserDao{
public static void testGetUsers() throws Exception{
Connection conn=null;
Statement statement=null;
ResultSet resultSet=null;
try{
conn=JdbcUtils.getConnetcion();
statement=conn.createStatement();
resultSet=statement.excuteQuery("select * from user");
while(resultSet.next()){
System.out.println(resultSet.getObject(1)+"\t"+resultSet.getObject(2));
}
}finally{
JdbcUtils.freeResource(resultSet,statement,conn);
}
}
}