java web1

来源：互联网发布：可可网络验证后台 xss 编辑：程序博客网时间：2024/06/06 12:39

1.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>学习</title></head><body><%!//jsp声明（加个！），可以 定义公用函数、全局变量、公用类String showMsg(String name,int score){return name+"你的成绩是："+score;}%><br><%out.print(showMsg("波波", 99));%></body></html>

2.jsp访问数据库

访问数据库的操作叫做JDBC,它提供了java对数据库进行操作的API

JDBC相关API存放在java.sql包中，主要的类如下：

java.sql.Connection:负责连接数据库

java.sql.Statement:负责执行数据库SQL语句

java.sql.ResultSet:负责存放查询结果

下面是简单的一个向数据库中插入数据的程序。

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ page import="java.sql.*" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>连接数据库</title></head><body><%//指定是oracle驱动Class.forName("oracle.jdbc.driver.OracleDriver");String url = "jdbc:oracle:thin:@localhost:1521:orcl";//获取连接Connection conn = DriverManager.getConnection(url,"web_shiyan","web_shiyan");Statement stat = conn.createStatement();String query = "insert into surname  values('张')";//执行sql语句，返回受这条sql语句影响的行数，即成功插入的行数int i = stat.executeUpdate(query);out.print("成功添加"+i+"行");//最后要关闭数据库连接stat.close();conn.close();%></body></html>

下面是一个从数据库中查询的程序

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ page import="java.sql.*" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>连接数据库</title></head><body><%//指定是oracle驱动Class.forName("oracle.jdbc.driver.OracleDriver");String url = "jdbc:oracle:thin:@localhost:1521:orcl";//获取连接Connection conn = DriverManager.getConnection(url,"web_shiyan","web_shiyan");Statement stat = conn.createStatement();String sql = "select * from topic";//执行sql语句ResultSet rs = stat.executeQuery(sql);//查询的结果保存在rs中while(rs.next()){//遍历结果集int tid = rs.getInt(1);//可以用列号获得String tname = rs.getString("tname");//也可以用列名获得数据out.println(tid+" "+tname+"<br>");}//最后要关闭数据库连接stat.close();conn.close();%></body></html>

0 0