JDBC+Servlet+JSP整合开发之25.JSP动作元素
�Cjsp:useBean
�Cjsp:setProperty
�Cjsp:getProperty
�Cjsp:forward
�Cjsp:include
�Cjsp:param
�C实例
?计算器
�Cjsp:setProperty
�Cjsp:getProperty
�Cjsp:forward
�Cjsp:include
�Cjsp:param
�C实例
?计算器
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? jsp:useBean
�C格式
? <jsp:useBean id="name" class="package.Class" />
�C目的
? 不需用到显式的Java编程就能够创建Java类的实例
�C注意
? 简单来说
�C<jsp:useBean id="book1" class=“com.amaker.Book" />
? 可以认为等同于下面的scriptlet
�C<% coreservlets.Book book1 = new com.amaker.Book(); %>
�C但jsp:useBean拥有下面两项额外的优势
? 从请求参数中导出对象的值更容易
? 在页面和servlet间共享对象更容易
�C格式
? <jsp:useBean id="name" class="package.Class" />
�C目的
? 不需用到显式的Java编程就能够创建Java类的实例
�C注意
? 简单来说
�C<jsp:useBean id="book1" class=“com.amaker.Book" />
? 可以认为等同于下面的scriptlet
�C<% coreservlets.Book book1 = new com.amaker.Book(); %>
�C但jsp:useBean拥有下面两项额外的优势
? 从请求参数中导出对象的值更容易
? 在页面和servlet间共享对象更容易
User.java
TestUseBean.jsp
测试：
下面我们使用动作元素jsp:useBean来实现哈~
TestUseBean.jsp
测试：
? jsp:setProperty
�C格式 ? <jsp:setProperty name="name“ property="property“ value="value"
/>
�C目的 ? 不需用到显式的Java编程就可以设置bean的属性（即调用setXxx方法）
�C注意 ? <jsp:setProperty name="book1“ property="title“ value=“amaker JSP" />
�C等价于下面的scriptlet
? <% book1.setTitle(“Java Web Dev!"); %>
�C格式 ? <jsp:setProperty name="name“ property="property“ value="value"
/>
�C目的 ? 不需用到显式的Java编程就可以设置bean的属性（即调用setXxx方法）
�C注意 ? <jsp:setProperty name="book1“ property="title“ value=“amaker JSP" />
�C等价于下面的scriptlet
? <% book1.setTitle(“Java Web Dev!"); %>
? jsp:getProperty
�C格式
? <jsp:getProperty name="name" property="property" />
�C目的
? 不需用到显式的Java编程就可以访问bean的属性（即调用getXxx
方法）
�C注意
? <jsp:getProperty name="book1" property="title" />
�C等价于下面的JSP表达式
? <%= book1.getTitle() %>
�C格式
? <jsp:getProperty name="name" property="property" />
�C目的
? 不需用到显式的Java编程就可以访问bean的属性（即调用getXxx
方法）
�C注意
? <jsp:getProperty name="book1" property="title" />
�C等价于下面的JSP表达式
? <%= book1.getTitle() %>
下面我们通过请求参数来获取
login.jsp
TestUseBean.jsp
测试：
同样我们也可以用param获取参数
TestUseBean.jsp
测试：
�Cjsp:forward
?转发请求到指定文件
?语法
�C<jsp:forward page=“URL”/>
?例如
�C<jsp:forward page=“/result.jsp” />
?转发请求到指定文件
?语法
�C<jsp:forward page=“URL”/>
?例如
�C<jsp:forward page=“/result.jsp” />
login.jsp
process.jsp
测试：
帐号michael跳转到成功页面。
非michael帐号跳转到失败页面。
? jsp:include
�C在页面中动态包含文件
�C语法
? <jsp:include page=“URL” flush=“true”/>
�C例如
? <jsp:include page=“header.jsp”flush=“true”/>
�C在页面中动态包含文件
�C语法
? <jsp:include page=“URL” flush=“true”/>
�C例如
? <jsp:include page=“header.jsp”flush=“true”/>
TestJspInclude.jsp
include.jsp
测试：
? jsp:param
�C获得请求参数
�C获得请求参数
TestJspInclude.jsp
include.jsp
测试：
�C实例
?计算器
?计算器
Calculator.jsp
<%@ page language= "java" import= "java.util.*" pageEncoding= "gbk"%>
<%@page import= "com.michael.jsp.CalculatorBean"%>
<%
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 'Calculator.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form name="f1" id="f1" action="<%=path %>/Calculator.jsp" method="post">
<jsp:useBean id="cb" class="com.michael.jsp.CalculatorBean"></jsp:useBean>
<jsp:setProperty property="*" name="cb"/>
<hr>
计算结果：<%
if(cb.getOperator()!=null){
try{
out.println(cb.getFirst()+cb.getOperator()+cb.getSecond()+"="+cb.getResult());
}catch(Exception e){
}
}else{
out.println("请输入！");
}
%>
<hr>
<table border="0">
<tr>
<td>第一个数:</td>
<td><input type="text" name="first"></td>
</tr>
<tr>
<td>操作符:</td>
<td>
<select name="operator">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
</td>
</tr>
<tr>
<td>第二个数:</td>
<td><input type="text" name="second"></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="计算"></td>
</tr>
</table>
</form>
</body>
</html>
<%@page import= "com.michael.jsp.CalculatorBean"%>
<%
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 'Calculator.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form name="f1" id="f1" action="<%=path %>/Calculator.jsp" method="post">
<jsp:useBean id="cb" class="com.michael.jsp.CalculatorBean"></jsp:useBean>
<jsp:setProperty property="*" name="cb"/>
<hr>
计算结果：<%
if(cb.getOperator()!=null){
try{
out.println(cb.getFirst()+cb.getOperator()+cb.getSecond()+"="+cb.getResult());
}catch(Exception e){
}
}else{
out.println("请输入！");
}
%>
<hr>
<table border="0">
<tr>
<td>第一个数:</td>
<td><input type="text" name="first"></td>
</tr>
<tr>
<td>操作符:</td>
<td>
<select name="operator">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
</td>
</tr>
<tr>
<td>第二个数:</td>
<td><input type="text" name="second"></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="计算"></td>
</tr>
</table>
</form>
</body>
</html>
CalculatorBean.java
package com.michael.jsp;
public class CalculatorBean {
private double first;
private double second;
private double result;
private String operator;
public double getFirst() {
return first;
}
public void setFirst( double first) {
this.first = first;
}
public double getSecond() {
return second;
}
public void setSecond( double second) {
this.second = second;
}
public double getResult() {
try {
if(operator!= null){
if(operator.equals( "+")){
result = first + second;
} else if(operator.equals( "-")){
result = first - second;
} else if(operator.equals( "*")){
result = first * second;
} else if(operator.equals( "/")){
result = first / second;
} else{
result = 0.0;
}
} else{
result = 0.0;
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public void setResult( double result) {
this.result = result;
}
public String getOperator() {
return operator;
}
public void setOperator(String operator) {
this.operator = operator;
}
}
public class CalculatorBean {
private double first;
private double second;
private double result;
private String operator;
public double getFirst() {
return first;
}
public void setFirst( double first) {
this.first = first;
}
public double getSecond() {
return second;
}
public void setSecond( double second) {
this.second = second;
}
public double getResult() {
try {
if(operator!= null){
if(operator.equals( "+")){
result = first + second;
} else if(operator.equals( "-")){
result = first - second;
} else if(operator.equals( "*")){
result = first * second;
} else if(operator.equals( "/")){
result = first / second;
} else{
result = 0.0;
}
} else{
result = 0.0;
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public void setResult( double result) {
this.result = result;
}
public String getOperator() {
return operator;
}
public void setOperator(String operator) {
this.operator = operator;
}
}
测试：
800/50
30+50
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