oracle脚本：drop table t_student cascade constraints;

/*==============================================================*/
/* Table: t_student                                           */
/*==============================================================*/
create table t_student  (
   s_id              char(10)                        not null,
   s_name             varchar2(20)                    not null,
   s_age              char(2)                         not null,
   s_sex              char(2)                         not null,
   s_class            varchar2(20),
   constraint PK_T_STUDENT primary key (s_id)
);

insert into t_student values('0001','张三','20','男','08级二班') ;
insert into t_student values('0002','李四','21','女','08级二班') ;
insert into t_student values('0003','王五','20','男','08级二班') ;
insert into t_student values('0004','赵柳','20','女','08级一班') ;
insert into t_student values('0005','杨梅','21','男','08级二班') ;
insert into t_student values('0006','刘海','23','女','08级一班') ;
insert into t_student values('0007','孙江','20','女','08级一班') ;
insert into t_student values('0008','苏灿','22','男','08级二班') ;
insert into t_student values('0009','王霞','23','女','08级一班') ;
insert into t_student values('0010','王猛','22','男','08级二班') ;
insert into t_student values('0011','张相','22','女','08级一班') ;
insert into t_student values('0012','香橙','20','女','08级一班') ;
insert into t_student values('0013','李心','21','女','08级二班') ;
insert into t_student values('0014','张强','20','男','08级一班') ;
insert into t_student values('0015','赵琳','21','女','08级一班') ;
insert into t_student values('0016','刘达','21','男','08级二班') ;
insert into t_student values('0017','苏惠','20','女','08级二班') ;
insert into t_student values('0018','贾瑞','20','女','08级一班') ;
insert into t_student values('0019','谷瑞坤','22','男','08级二班') ;
insert into t_student values('0020','祥还','21','男','08级一班') ;
commit;

??采用单利模式创建DbUtil类获得Connection对象：package com.stmcc.test.util;

import java.sql.*;

public class DbUtil {

	private static final String driver = "oracle.jdbc.driver.OracleDriver" ;
	private static final String url = "jdbc:oracle:thin:@10.10.10.2:1521:orcl" ;
	private static final String username = "test" ;
	private static final String password = "test" ;
	public static Connection getConnection(){
		Connection conn = null ;
		try{
			Class.forName(driver) ;
			conn = DriverManager.getConnection(url, username, password) ;
		}catch(Exception e){
			e.printStackTrace() ;
		}
		return conn ;
	}

	public static void close(Connection conn) {
		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	
	public static void close(PreparedStatement pstmt) {
		if (pstmt != null) {
			try {
				pstmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	
	public static void close(ResultSet rs ) {
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) {
		System.out.println(DbUtil.getConnection());
	}
}

?创建学生实体类：package com.stmcc.test;

public class Student {

	private String s_id ;
	private String s_name ;
	private String s_age ;
	private String s_sex ;
	private String s_class ;
	public String getS_id() {
		return s_id;
	}
	public void setS_id(String s_id) {
		this.s_id = s_id;
	}
	public String getS_name() {
		return s_name;
	}
	public void setS_name(String s_name) {
		this.s_name = s_name;
	}
	public String getS_age() {
		return s_age;
	}
	public void setS_age(String s_age) {
		this.s_age = s_age;
	}
	public String getS_sex() {
		return s_sex;
	}
	public void setS_sex(String s_sex) {
		this.s_sex = s_sex;
	}
	public String getS_class() {
		return s_class;
	}
	public void setS_class(String s_clas