多个jsp页面共享Java bean

  1. 通过jsp的内置对象—request对象获取参数:

             通过超链接传参:

                     例:把a.jsp中i的值传到b.jsp中:

                          在a.jsp页面中的核心代码为:

                               <a href="b.jsp?i=1">传参</a>     (说明:给i赋值时也可以用jsp表达式,例如i=<%变量名 %>)

                          在b.jsp页面中的核心代码为:

                              <%String j=request.getParameter("i"); %>

                              <%=j %>    

  2.  

              通过request.setAttribute()方法:

                      例:把a.jsp中表单中的name的值传送到b.jsp中:                            

                          在a.jsp页面中的核心代码为:

                               <%request.setAttribute(name,"Danny");%>

                          在b.jsp页面中的核心代码为:

                              <%String getName=request.getParameter("name"); %>

  3.  

              通过表单传参:

                      例:把a.jsp中表单中的name的值传送到b.jsp中:

                           在a.jsp页面中的核心代码为:

                                <form action="b.jsp" method="post">

                                     <ul>

                                           <li><input type="text" name="username">

                                           <li>w<input type="submit" name="submit" value="提交">

                                     <ul>

                                </form>

                           在b.jsp页面中的核心代码为;

                                <%String getUserName=request.getParameter("username");>

                                <%=getUserName %>

  4.  

              通过表单的隐藏域传参:

                       例:把a.jsp中定义的变量传送到b.jsp中;

                            在a.jsp中的核心代码为:

                                 <%!int a=4; %>                             <form action="b.jsp" method="post">                                   <input type="hidden" name="b" value=<%a%>>

                                       <input type="submit" value="提交">

                                 </form>

                            在b.jsp中的核心代码为:

                                 <%int c=(Integer)request.getAttribute("b"); %>    

                                (上段代码或者为<%String c=request.getAttribute("c").toString(); %>等等,类型转换通java一样)                             <%=c %>

                            运行结果:变量a=4的值通过表单隐藏域b传到b.jsp中的c中。

    2、通过JavaBean获取表单信息:

                例:用JavaBean获取用户登录表单信息:

                     Login.jsp中的核心代码为:

                       <form action="Deal.jsp" method="post">

                             <ul>

                                  <li>用户名:<input type="text" name="username">

                                  <li>密码:<input type="password" name="password">

                                  <li><input type="submit" name="submit" value="登录">

                             </ul>

                      </form>

                    JavaBean中的核心代码为:

                       package com;

                       public class UserBean{

                              private String username;

                              private String password;

                              public String getUserName(){

                                     return username;

                              }

                              public void setUserName(String username){

                                     this.username=username; 

                              }

                              public String getPassword(){

                                     return password;

                              }

                              public void setPassword(String password){

                                     this.password=password;

                              }

                        }

                     Deal.jsp中的核心代码为:

                       <jsp:useBean id="user" class="com.UserBean" >

                       <jsp:setProperty name="user" property="*">

                       <%String username=user.getUserName();%>

                       <%String password=user.getPassword();%>

                       得到的用户名为:<%=username%><br>

                       得到的密码为:<%=password%>

                  其中,Deal.jsp中的<jsp:setProperty name="user" property="*">中的星号是表示对所有同名的属性赋值,当然还可以对属性选择性地赋值: <jsp:setProperty name="user" property="username">、<jsp:setProperty name="user" property="password">等。

原文地址:https://www.cnblogs.com/frankzone/p/7663736.html