怎样编写一个java程序能通过jdbc访问数据库实现对数据库的插入、删除、修改和查询？

1.增加
String s1="insert into tableNames (id,name,password) values(myseq.nextval,?,?);"
Class.forName(driver);
Connection conn = DriverManager.getConnection(url,dbUser,dbPwd);
PreparedStatement prepStmt = conn.prepareStatement(s1);
prepStmt.setString(1,name);
prepStmt.setString(2,password);
ResultSet rs=stmt.executeUpdate();
2、删除
String s2="delete from tbNames where name=?";
Class.forName(driver);
Connection conn = DriverManager.getConnection(url,dbUser,dbPwd);
PreparedStatement prepStmt = conn.prepareStatement(s2);
prepStmt.setString(1,name);
ResultSet rs=stmt.executeUpdate();
3、修改
String s3=“update tbNames set name=? where id=?”;
Class.forName(driver);
Connection conn = DriverManager.getConnection(url,dbUser,dbPwd);
PreparedStatement prepStmt = conn.prepareStatement(s3);
prepStmt.setString(1,name);
prepStmt.setString(2,id);
ResultSet rs=stmt.executeUpdate();
4、查询
String s4="select id,name,password from tbNames";
Class.forName(driver);
Connection conn = DriverManager.getConnection(url,dbUser,dbPwd);
Statement stmt=conn.createStatement();
ResultSet rs = stmt.executeQuery(s4);
while(rs.next){
int id=rs.getInt(1);
String name = rs.getString(2);
String pwd=rs.getString(3);
System.out.println(id+name+pwd); }

以上四步必须都得关闭连接；！！！
rs.close();
stmt.close();
conn.close();