更新时间:2022-09-10 08:01:29
在java web的学习过程里面,javabean和servlet都是比较重要的两部分内容。在开发中javabean可以用来实现一些业务逻辑或者封装一些业务的对象;而Servlet不但可以用来处理HTTP请求中的业务逻辑,还可以输出HTML代码来显示指定页面。下面就通过录入用户信息实例展开详细的分析,以便更方便体验JavaBean与Servlet在JSP页面中应用的两种不同的实现过程
JavaBean
在JSP页面中应用JavaBean主要通过JSP动作标签<jsp:useBean>、<jsp:getProperty>、<jsp:setProperty>来实现对JavaBean对象的操作。
先来了解一下学习JavaBean中有几个比较重要的知识点:
setXXX()方法//提供为JavaBean中的属性赋值的方法
getXXX()方法//提供公共的访问方法
<jsp:useBean>:实例化javaBean对象
<jsp:getProperty>:获取JavaBean的属性信息。
<jsp:setProperty>:对JavaBean的属性在JSP页面中赋值
本实例中实现档案管理系统,在其中录入用户信息功能。其开发步骤如下:
(1)创建一个Person类,将其放置在com.lxy.bean包中,实现对用户信息封装。在person类中包含4个属性.
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package com.lxy.bean;
public class Person {
private String name;
private int age;
private String sex;
private String add;
public String getName(){
return name;
} public void setName(String name){
this .name=name;
} public int getAge(){
return age;
} public void setAge( int age){
this .age=age;
} public String getSex(){
return sex;
} public void setSex(String sex){
this .sex=sex;
} public String getAdd(){
return add;
} public void setAdd(String add){
this .add=add;
} } |
(2)创建程序的主页面index.jsp,放置录入用户信息的表单。(提示:表单属性名称***设置成为JavaBean中的属性名称,这样就可以通过“<jsp:setProperty property="*">”的形式来接收所有参数,减少代码量。如果将年龄文本框name属性设置为age,它对应Person类的age.)
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<%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%>
<!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=GB18030" >
< title >添加用户信息</ title >
</ head >
< body >
< form action = "deal.jsp" method = "post" >
< table align = "center" width = "400" height = "200" border = "1" >
< tr >
< td align = "center" colspan = "2" height = "40" >
< b >添加用户信息</ b >
</ td >
</ tr >
< tr >
< td align = "right" >姓 名:
</ td >
< td >< input type = "text" name = "name" >
</ td >
</ tr >
< tr >
< td align = "right" >年 龄:
</ td >
< td >< input type = "text" name = "age" >
</ td >
</ tr >
< tr >
< td align = "right" >性 别:
</ td >
< td >< input type = "text" name = "sex" >
</ td >
</ tr >
< tr >
< td align = "right" >住 址:
</ td >
< td >< input type = "text" name = "add" >
</ td >
</ tr >
< tr >
< td align = "center" colspan = "2" >
< input type = "submit" value = "添加" >
</ td >
</ tr >
</ table >
</ form >
</ body >
</ html >
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(3)创建deal.jsp的处理页,用于对index.jsp页面中表单的提交请求处理。该页面将获取表单所提交的所有信息,然后将获取的用户信息输出到页面中。
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<%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%>
<!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=GB18030" >
< title >处理页</ title >
</ head >
< body >
<%request.setCharacterEncoding("GB18030"); %> //通过request的setCharacterEncoding()方法指定编码格式进行解决乱码问题 < jsp:useBean id = "person" class = "com.lxy.bean.Person" scope = "page" >
< jsp:setProperty name = "person" property = "*" />
</ jsp:useBean >
< table align = "center" width = "400" >
< tr >
< td align = "right" >姓 名:
</ td >
< td >< jsp:getProperty property = "name" name = "person" />
</ td >
</ tr >
< tr >
< td align = "right" >年 龄:
</ td >
< td >< jsp:getProperty property = "age" name = "person" />
</ td >
</ tr >
< tr >
< td align = "right" >性 别:
</ td >
< td >< jsp:getProperty property = "sex" name = "person" />
</ td >
</ tr >
< tr >
< td align = "right" >住 址:
</ td >
< td >< jsp:getProperty property = "add" name = "person" />
</ td >
</ tr >
</ table >
</ body >
</ html >
|
最后运行页面:
显示
Servlet
Servlet与JavaBean的方法有比较大的区别。
实现用户信息的添加功能,并创建字符编码过滤器,避免中文乱码现象的产生。
(1)创建字符编码过滤器对象,其名称为CharactorFilter类。该类实现了javax.servlet.Filter接口,并在doFilter()方法中对请求中的字符编码格式进行设置:
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package com.lixiyu;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
public class CharactorFilter implements Filter{
String encoding= null ; //字符编码
public void destroy(){
encoding= null ;
} public void doFilter(ServletRequest request,ServletResponse response
,FilterChain chain) throws IOException,ServletException{
if (encoding!= null ){ //判断字符编码是否为空
request.setCharacterEncoding(encoding); //设置request的编码格式
response.setContentType( "text/html;charset=" +encoding); //设置response字符编码格式
}
chain.doFilter(request, response); //传递到下一过滤器
} public void init(FilterConfig filterConfig) throws ServletException{
encoding=filterConfig.getInitParameter( "encoding" ); //获取初始化参数
} } |
(2)创建了过滤器对象之后,需要对过滤器进行一定的配置才可以正常使用:
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< filter >
< filter-name >CharactorFilter</ filter-name >
< filter-class >com.lixiyu.CharactorFilter</ filter-class >
< init-param >
< param-name >encoding</ param-name >
< param-value >UTF-8</ param-value >
</ init-param >
</ filter >
< filter-mapping >
< filter-name >CharactorFilter</ filter-name >
< url-pattern >/*</ url-pattern >
</ filter-mapping >
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技巧:在web.xml文件中配置过滤器,其过滤器的URL映射可以使用正则表达式进行配置,如果上面中使用的“/*”来匹配所有请求。
(3)创建AddServlet类,继承HttpServlet,是处理添加用户信息请求的Servlet对象:
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package com.lixiyu;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/** * Servlet implementation class AddServlet
*/
public class AddServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public AddServlet() {
super ();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { //处理GET请求
// TODO Auto-generated method stub
doPost(request,response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { //处理POST请求
// TODO Auto-generated method stub
PrintWriter out=response.getWriter(); //获取PrintWriter
String name=request.getParameter( "name" ); //获取用户信息
String age=request.getParameter( "age" );
String sex=request.getParameter( "sex" );
String add=request.getParameter( "add" );
out.print( "<h2>用户信息添加成功</h2><hr>" ); //输出用户信息
out.print( "姓名:" +name+ "<br>" );
out.print( "年龄:" +age+ "<br>" );
out.print( "性别:" +sex+ "<br>" );
out.print( "地址:" +add+ "<br>" );
out.flush(); //刷新流
out.close(); //关闭流
}
} |
AddServlet类主要通过doPost()方法实现添加图书管理信息请求的处理,其方式是将所获取的信息数据直接输出到页面中。
(4)在web.xml中对Servlet进行配置:
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< servlet >
< servlet-name >AddServlet</ servlet-name >
< servlet-class >com.lixiyu.AddServlet</ servlet-class >
</ servlet >
< servlet-mapping >
< servlet-name >AddServlet</ servlet-name >
< url-pattern >/AddServlet</ url-pattern >
</ servlet-mapping >
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(5)创建index.jsp的页面,用于放置表单:
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<%@ 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 >添加用户信息</ title >
</ head >
< body >
< form action = "AddServlet" method = "post" >
< table align = "center" border = "1" width = "350" >
< tr >
< td class = "2" align = "center" colspan = "2" >
< h2 >添加用户信息</ h2 >
</ td >
</ tr >
< tr >
< td align = "right" >姓 名:</ td >
< td >
< input type = "text" name = "name" >
</ td >
</ tr >
< tr >
< td align = "right" >年 龄:</ td >
< td >
< input type = "text" name = "age" >
</ td >
</ tr >
< tr >
< td align = "right" >性 别:</ td >
< td >
< input type = "text" name = "sex" >
</ td >
</ tr >
< tr >
< td align = "right" >地 址:</ td >
< td >
< input type = "text" name = "add" >
</ td >
</ tr >
< tr >
< td class = "2" align = "center" colspan = "2" >
< input type = "submit" value = "添 加" >
</ td >
</ tr >
</ table >
</ form >
</ body >
</ html >
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最后运行:
显示
本文转自lixiyu 51CTO博客,原文链接:http://blog.51cto.com/lixiyu/1351666,如需转载请自行联系原作者