jsp
page指令
使用此属性，可以定义一个jsp页面的相关属性
<%@ page contentType="text/html;charset=UTF-8" language="java" %>设置该页面的类型为text/html类型，其中编码为Unicode 类型的UTF-8 语言为java
从Tomcat安装目录中可以找到可以使用的MIME类型
<mime-mapping> ???<extension>ait</extension> ???<mime-type>application/vnd.dvb.ait</mime-type></mime-mapping>错误页设置
设置page指令的errorPage属性，设置错误页
<%-- ?Created by IntelliJ IDEA. ?User: ming ?Date: 19-3-6 ?Time: 下午9:29 ?To change this template use File | Settings | File Templates.--%><%@ page contentType="application/vnd.dvb.ait;charset=UTF-8" language="java" %><%@ page errorPage="error.jsp" %><html> ?<head> ???<title>$Title$</title> ?</head> ?<body> ???<% ?????// 运行错误 ?????int result = 10 / 0; ???%> ?</body></html>设置如果出现错误，跳转到error.jsp文件
错误页的跳转属于服务器端跳转
数据库连接操作
maven安装驱动
访问网址
https://search.maven.org/artifact/mysql/mysql-connector-java/8.0.15/jar输入依赖
<dependency> ?<groupId>mysql</groupId> ?<artifactId>mysql-connector-java</artifactId> ?<version>8.0.15</version></dependency>jsp书写代码，并网页展示
<%@ page import="java.sql.*" %><html><body><h2>Hello World!</h2><%! ???// 数据库驱动程序 ???public static final String DBDRIVER = "com.mysql.cj.jdbc.Driver"; ???// 数据库连接地址 ???public static final String DBURL = "jdbc:mysql://47.94.95.84:32786/test"; ???// 用户名 ???public static final String DBUSER = "root"; ???// 密码 ???public static final String DBPASS = "ABCcba20170607";%><% ???// 声明数据库连接对象 ???Connection connection = null; ???// 连接 ???PreparedStatement preparedStatement = null; ???// 结果集 ???ResultSet resultSet = null; ???String sql = "SELECT * from emp";%><% ???try{ ???????Class.forName(DBDRIVER); ???????// 数据库连接 ???????connection = DriverManager.getConnection(DBURL, DBUSER, DBPASS); ???????// 实例化sql ???????preparedStatement = connection.prepareStatement(sql); ???????// 查询 ???????resultSet = preparedStatement.executeQuery(); ???????while(resultSet.next()){ ???????????int empon = resultSet.getInt(1); ???????????String ename = resultSet.getString(2); ???????????String job = resultSet.getString(3); ???????????%> ???????????????<%=empon%> ???????????????<%=ename%> ???????????????<%=job%> ???????????<% ???????} ???}catch (Exception e){ ???????System.out.println(e); ???}finally { ???????resultSet.close(); ???????preparedStatement.close(); ???????connection.close(); ???}%></body></html>包含指令
网页分为头尾中
静态包含
在jsp编译的时候插入一个包含文本或代码的文件。包含过程为静态的,代码文件包含，生成一个完整的jsp文件，再次包含生成class文件，加载进入容器。
<html><body> ???<%@include file="info.html"%> ???<%@include file="info.inc"%></body></html>动态包含
<%-- ?Created by IntelliJ IDEA. ?User: ming ?Date: 19-3-9 ?Time: 下午3:43 ?To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %>参数1<%=request.getParameter("name")%>参数2<%=request.getParameter("info")%><%-- ?Created by IntelliJ IDEA. ?User: ming ?Date: 19-3-9 ?Time: 下午4:51 ?To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head> ???<title>Title</title></head><body> ???<% ???????String username = "LiHua"; ???%> ???<h1>动态传递参数</h1> ???<jsp:include page="./receive_param.jsp"> ???????<jsp:param name="name" value="<%=username%>"/> ???????<jsp:param name="info" value="ming"/> ???</jsp:include></body></html>运行以后可以发现显示出结果
两种包含，静态包含是先包含，后处理，动态包含为先处理后包含
跳转指令
此跳转为服务端跳转
即一个request传递到另外一个page
<%-- ?Created by IntelliJ IDEA. ?User: ming ?Date: 19-3-9 ?Time: 下午5:14 ?To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><h1>这是跳转后的页面</h1><h2><%=request.getParameter("name")%></h2><h2><%=request.getParameter("info")%></h2><%-- ?Created by IntelliJ IDEA. ?User: ming ?Date: 19-3-9 ?Time: 下午5:11 ?To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><% ???String username = "LiHua";%><jsp:forward page="forward_demo02.jsp"> ???<jsp:param name="name" value="<%=username%>"/> ???<jsp:param name="info" value="ming"/></jsp:forward>jsp 基础语法
原文地址：https://www.cnblogs.com/melovemingming/p/10503957.html