1.JSP的配置：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP ‘register.jsp‘ starting page</title>
</head>
<body>
<pre>
JSP:java servlet page
jsp也是一个servlet:要继承HttpServlet--->service方法
jsp当被访问的时候，tomcat会自动把它编译成Java class，会生成一个遵循某个命名规则的clas和Java文件(以login.jsp为例，首先会把.转换为_，然后进行连接--->login_jsp.java/class，这里的命名规则并不遵循Java的驼峰命名规则)
这个class继承了--->org.apache.jasper.runtime.HttpJspBase--->拥有_jspService
org.apache.jasper.runtime.HttpJspBase继承了---->HttpServlet--->重写了service方法---->调用了这个class的_jspService方法
也就是相当于tomcat把jsp文件生成Java类继承了httpservlet
所以说jsp也就是一个servlet
---->必须要配置
<servlet>
<servlet-name></servlet-name>
<servlet-class></servlet-class>
</servlet>
<servlet-mapping>
<servlet-name></servlet-name>
<url-pattern></url-pattern>
</servlet-mapping>
jsp在tomcat的conf文件下web.xml进行配置
<servlet>
<servlet-name>jsp</servlet-name>
<servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
<init-param>
<param-name>fork</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>xpoweredBy</param-name>
<param-value>false</param-value>
</init-param>
<load-on-startup>3</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>jsp</servlet-name>
<url-pattern>*.jsp</url-pattern>
<url-pattern>*.jspx</url-pattern>
</servlet-mapping>
所以org.apache.jasper.servlet.JspServlet来处理以jsp为结尾的路径
JspServlet-->就是一个servlet--->重写了service方法--->把jsp(warrper)文件转换为class文件
</pre>
</body>
</html>
2.动态导入和静态导入JSP文件：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%-- errorPage只能保护运行时异常(404,405,401)，不能保护检查时异常(500,600) --%>
<%@ page isErrorPage="true" %><%-- 标记本页面是否为错误页面，提供后来人观看代码 --%>
<%@ page errorPage="error.jsp" %>
<%-- <%@ page import="cn.zzsxt.lee.servlet.*" %> --%><%-- 导入servlet包下的所有Java文件 --%>
<%@ page import="cn.zzsxt.lee.servlet.Test" %><%-- 导入Test.java --%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘login.jsp‘ starting page</title>
</head>
<body>
<pre>
jsp即可以写html代码，也可以写Java代码
jsp第一个语法：
<!-- 是把两个jsp文件合并成了一个jsp文件 -->
<!-- 静态导入:首先会把两个jsp文件合成一个，然后再通过tomcat进行编译，所以只编译了一次，高耦合，所以效率也会提高 -->
<%@ include file="top.jsp" %><!-- 无论定位到页面的某一个位置，都能进行导入jsp文件，说白了也就是无论放在任何位置，就把导入的jsp放在哪里 -->
<%
String name = "zhangsan";
System.out.println(name);
// String name2 = "lisi1";// 如果使用<%@ include file="top.jsp" %>导入，报两个变量名不能相同
String name3;
/* int x = 1/0; */
//System.out.println(name3);
// 运行时异常
// 提示错误信息
// 只有运行时异常，才会被errorpage保护
// 检查时异常
// 直接强行中断正在运行的程序
Test test = new Test();
test.getName();
%>
<%=name%>
<%=name2%>
<%-- <%=x%> --%>
</pre>
<a href="register.jsp">我是跳转页面用的</a>
<!-- 动态导入，会生成两个class文件，从而tomcat编译了两次 -->
<jsp:include page="footer.jsp"></jsp:include>
</body>
</html>
3.重定向和请求转发：
请求转发：
1.request.getRequestDispatcher("需要跳转的路径").forward(request, response);
发送一次请求
地址栏不发生改变
request可以传递参数(能参数共享)
请求转发并不能访问到外部资源(外部的地址)
重定向：
2.response.sendRedirect("需要跳转的路径");
发送两次请求
地址栏发生改变
response不能传递参数(不能参数共享)，如果想使用response进行参数传递，就得手动加载，自力更生
重定向可以访问外部资源
请求转发
当需要传递参数的时候
访问内部资源的时候建议使用请求转发(服务器内部之间的调用)
重定向
访问外部资源
比较隐私和保密的地址一般推荐使用重定向
4.使用JSP实现数据库的增删改查实例：
注册：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘register.jsp‘ starting page</title>
</head>
<body>
<h1>注册页面</h1>
<form action="deal_register.jsp" method="post">
用户名:
<input type="text" name="username" />
<br /> 密码:
<input type="password" name="pwd" /><br />
重复密码:
<input type="password" name="repwd" /><br />
手机号:
<input type="text" name="phone" /><br />
爱好:
<input type="checkbox" name="hobby" value="football" />足球
<input type="checkbox" name="hobby" value="basketball" />篮球
<input type="checkbox" name="hobby" value="Pingpong" />乒乓球
<br />
性别:
<input type="radio" name="sex" value="male" />男
<input type="radio" name="sex" value="female" />女<br />
<input type="submit" value="提交" />
</form>
</body>
</html>
处理注册信息存入数据库：
<%@ page language="java" import="java.util.*, java.sql.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘deal_register.jsp‘ starting page</title>
</head>
<body>
<%
// 第一步：获取input的值(也就是用户注册的信息)
String username = request.getParameter("username");
String password = request.getParameter("pwd");
String phoneNumber = request.getParameter("phone");
long phone = Long.parseLong(phoneNumber);
// String hobby1 = request.getParameter("hobby");
String[] hobby = request.getParameterValues("hobby");
String[] sex = request.getParameterValues("sex");
String hobbys= "";// "football,basketball,pingpong"
//hobby.length为3
for(int i = 0;i < hobby.length; i++) {
/* if(hobby.length-1 > i) {
hobbys +=hobby[i]+",";// 最后一位是,
} else {
hobbys +=hobby[i];
} */
hobbys +=hobby[i]+",";
}
hobbys = hobbys.substring(0,hobbys.length()-1);
//String sex1 = request.getParameter("sex");// 如果是单选或者多选的话，使用request.getParameter()--->on，规定无论是单选还是多选或者下拉使用request.getParameterValues();
// 第二步：插入数据，id使用UUID
//1.导入ojdbc6.jar
//2.加载驱动(反射)
Class.forName("oracle.jdbc.driver.OracleDriver");
//3.获取连接
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","scott","scott");
//4.获取预编译的statement(String sql)
String sql = "insert into students (id, stu_name, stu_age, stu_pwd, stu_hobby, stu_sex, stu_phone) values(?,?,?,?,?,?,?)";
PreparedStatement ps = conn.prepareStatement(sql);
//5.设置参数ps.setxxxx
ps.setString(1,UUID.randomUUID().toString());
ps.setString(2, username);
ps.setInt(3, 32);
ps.setString(4, password);
ps.setString(5, hobbys);
ps.setString(6,sex[0]);
ps.setLong(7, phone);
//6.调用executeUpdate();--->返回值为受影响的行数
int result = ps.executeUpdate();
//7.判断接收的int类型数据，判断是否大于0(大于0成功，小于0失败)
if(result > 0) {
// 成功
} else {
// 失败
}
%>
</body>
</html>
登录：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘login.jsp‘ starting page</title>
</head>
<body>
<form action="deal_login.jsp" method="post">
用户名：
<input type="text" name="username" />
<br /> 密码：
<input type="password" name="pwd" />
<input type="submit" value="提交" />
</form>
</body>
</html>
处理登录，预跳转至主页处理的界面（查询数据库全部数据）：
<%@ page language="java"
import="java.util.*, java.sql.*, cn.zzsxt.lee.web.entity.*"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘deal_login.jsp‘ starting page</title>
</head>
<body>
<%
String username = request.getParameter("username");
String password = request.getParameter("pwd");
//1.加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
//2.获取连接
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "scott");
//3.获取预编译的statement
String sql = "select * from teacher where name=? and password=?";
PreparedStatement ps = conn.prepareStatement(sql);
//4.设置参数
ps.setString(1, username);
ps.setString(2, password);
//5.调用executeQuery();-->返回ResultSet
ResultSet rs = ps.executeQuery();
//6.遍历结果集
Teacher teacher = new Teacher();
while (rs.next()) {
teacher.setId(rs.getInt("id"));
teacher.setUsername(rs.getString("name"));
teacher.setPassword(rs.getString("password"));
teacher.setDescription(rs.getString("description"));
}
//7.判断是否查询出数据
if (teacher.getUsername() != null && !"".equals(teacher.getUsername())) {// 把“”放在前面，防止空指针
// 成功，跳转主页面的处理页面
// request.getRequestDispatcher("deal_index.jsp").forward(request, response);// 跳转页面
request.getRequestDispatcher("frameset_index.jsp").forward(request, response);// 跳转页面
} else {
// 失败，跳转404
//response.sendRedirect("404.jsp");
request.getRequestDispatcher("404.jsp").forward(request, response);
}
%>
</body>
</html>
主页处理界面，预跳转至主页：
<%@ page language="java"
import="java.util.*, java.sql.*, cn.zzsxt.lee.web.entity.*"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘deal_index.jsp‘ starting page</title>
</head>
<body>
<%
//1.加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
//2.获取连接
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "scott");
//3.获取预编译的statement
String sql = "select * from students";
PreparedStatement ps = conn.prepareStatement(sql);
//4.调用executeQuery();-->返回ResultSet
ResultSet rs = ps.executeQuery();
//5.遍历结果集
// 定义一个泛型为Student的List集合
List<Student> list = new ArrayList<Student>();
while (rs.next()) {
Student student = new Student();
student.setId(rs.getString("id"));
student.setStuName(rs.getString("stu_name"));
student.setStuPassword(rs.getString("stu_pwd"));
list.add(student);
}
//6.判断list的长度大于0
if(list.size() > 0) {
// 成功，跳转到主页面
request.setAttribute("list", list);//--->Map.get("key");--->map.put("name",24);Map<String, Object>
request.getRequestDispatcher("index.jsp").forward(request, response);
} else {
// 失败
}
%>
</body>
</html>
跳转至主页，显示所有数据，及修改和删除的功能：
<%@ page language="java" import="java.util.*, cn.zzsxt.lee.web.entity.*"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘index.jsp‘ starting page</title>
<script type="text/javascript">
function trueDelete(id) {
if (confirm("您确定要删除数据么？")) {
window.location.href = "deal_delete.jsp?id=" + id;
}
}
</script>
</head>
<body>
<table border="1">
<thead>
<tr>
<th>学生编号</th>
<th>学生姓名</th>
<th>学生密码</th>
<th>操作</th>
</tr>
</thead>
<tbody>
<%
List<Student> listStudent = (List<Student>) request.getAttribute("list");
for (int i = 0; i < listStudent.size(); i++) {
listStudent.get(i).getId();// 获取student对象的id
%>
<%-- jsp的注释 --%>
<tr>
<!-- 一个tr代表了一行，说白了就是代表一个student对象 -->
<td><%=listStudent.get(i).getId()%></td>
<!-- <%--<%= %>--%>输出页面 -->
<td><%=listStudent.get(i).getStuName()%></td>
<td><%=listStudent.get(i).getStuPassword()%></td>
<td><a href="javascript:void(0);"
onclick="trueDelete(‘<%=listStudent.get(i).getId()%>‘);">删除</a>
<a href="select_by_id.jsp?id=<%=listStudent.get(i).getId()%>">修改</a>
</td>
<!-- 删除功能(主键id删除)需要传递一个参数，同样需要操作数据库，需要deal_delete.jsp进行处理 -->
</tr>
<%
}
%>
</tbody>
</table>
</body>
</html>
删除功能，删除处理界面，预跳转至主页处理界面（查询删除后还剩的数据，即所有数据）
<%@ page language="java" import="java.util.*, java.sql.*"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘deal_delete.jsp‘ starting page</title>
</head>
<body>
<%
//所有通过路径传递的参数都要使用request.getParameter()
String id = request.getParameter("id");
//1.加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
//2.获取连接
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "scott");
//3.获取预编译的statement
String sql = "delete from students where id=?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1, id);
int result = ps.executeUpdate();
if (result > 0) {
//成功
request.getRequestDispatcher("deal_index.jsp").forward(request, response);
} else {
// 失败
}
%>
</body>
</html>
修改功能，首先跳转至查询某一行的界面，预跳转至修改界面
<%@ page language="java"
import="java.util.*, java.sql.*, cn.zzsxt.lee.web.entity.*"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘select_by_id.jsp‘ starting page</title>
</head>
<body>
<%
String id = request.getParameter("id");
// 进行查询(通过id)
//1.加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
//2.获取连接
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "scott");
//3.获取预编译的statement
String sql = "select * from students where id=?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1, id);
//4.调用executeQuery();-->返回ResultSet
ResultSet rs = ps.executeQuery();
//5.遍历结果集
Student stu = new Student();
while (rs.next()) {
stu.setId(rs.getString("id"));
stu.setStuName(rs.getString("stu_name"));
stu.setStuPassword(rs.getString("stu_pwd"));
}
if (stu.getId() != null) {
request.setAttribute("stu", stu);
request.getRequestDispatcher("update.jsp").forward(request, response);
} else {
// 跳转报错页面
}
%>
</body>
</html>
修改界面，以form表单的形式显示让用户动态修改，预提交至修改处理界面
<%@ page language="java" import="java.util.*, cn.zzsxt.lee.web.entity.*"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘update.jsp‘ starting page</title>
</head>
<body>
<%
Student stu = (Student) request.getAttribute("stu");
%>
<form action="deal_update.jsp" method="post">
学生编号:
<input type="text" value="<%=stu.getId()%>" name="id" readonly="readonly" />
<br /> 学生姓名:
<input type="text" value="<%=stu.getStuName()%>" name="username" />
<br /> 学生密码:
<input type="text" value="<%=stu.getStuPassword()%>" name="pwd" />
<br />
<input type="submit" value="修改" />
</form>
</body>
</html>
修改界面，修改数据库中的数据，预跳转至主页处理界面（查询修改后的数据，即所有数据）
<%@ page language="java" import="java.util.*, java.sql.*"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘deal_update.jsp‘ starting page</title>
</head>
<body>
<%
String id = request.getParameter("id");
String username = request.getParameter("username");
String pwd = request.getParameter("pwd");
//1.加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
//2.获取连接
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "scott");
//3.获取预编译的statement
String sql = "update students set stu_name=?, stu_pwd=? where id=?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1, username);
ps.setString(2, pwd);
ps.setString(3, id);
int result = ps.executeUpdate();
if (result > 0) {
response.sendRedirect("deal_index.jsp");
return;
//request.getRequestDispatcher("deal_index.jsp").forward(request, response);//forward标识了跳转页面的规则，携带着request和response一起跳转页面，所以请求转发才可以传递参数
//System.out.println("我是转发之后的代码，我被执行了");
// 如果使用两个response或者request的情况下，就会报错Cannot call sendRedirect() after the response has been committed
// 但是重定向直接报500，中断程序，请求转发不会中断程序，可以继续运行
//response.sendRedirect("404.jsp");
} else {
//跳转错误页面
response.sendRedirect("404.jsp");
return;
}
%>
</body>
</html>
时间： 2024-10-10 00:31:36