• struts 韩顺平


    基于struts的登录验证:
    1.新建web项目;
    2.将struts的开发包加入web工程
    3.编写login.jsp
    4.编写ActionForm(用户表单)Action分控制器;
    5.编写struts-config.xml文件,该文件用于配置action actionform的对应关系,和跳转位置,一般放在WEB-INF目录下
    6.编写成功失败页面jsp;
    7.配置web.xml文件,在该文件中配置struts-config.xml文件
    8.测试ok

    扩展
    1.在登陆成功之后显示用户名;
    2.使用filter配合struts解决中文乱码;
       写一个过滤器,并设置request.setCharacterEncoding("utf-8");

    1. public class MyFilter extends HttpServlet implements Filter {
    3. 	@Override
    4. 	public void doFilter(ServletRequest request, ServletResponse response,
    5. 			FilterChain filter) throws IOException, ServletException {
    6. 		// TODO Auto-generated method stub
    7. 		request.setCharacterEncoding("utf-8");//设置编码
    8. 		filter.doFilter(request, response);//必须
    9. 	}
    11. 	@Override
    12. 	public void init(FilterConfig arg0) throws ServletException {
    13. 		// TODO Auto-generated method stub
    14. 		
    15. 	}
    17. }
        在web.xml文件中配置过滤器:
    1. 	<!-- 配置filter -->
    2. 	<filter>
    3. 	<filter-name>MyFilter</filter-name>
    4. 	<filter-class>filter.MyFilter</filter-class>
    5. 	</filter>
    6. 	<filter-mapping>
    7. 	<filter-name>MyFilter</filter-name>
    8. 	<url-pattern>/*</url-pattern>
    9. 	</filter-mapping>
    3.struts-config.xml 
    4.scope:
    5.每个action都是单态的,包括ActionServlet;
       单态:指在程序运行过程中始终只有一个实例对象;
    6.struts-config.xml 不一定在WEB-INF目录下,也不一定只有一个只需在web.xml文件配置即可.
    1. 	<init-param>
    2. 	<param-name>config</param-name>
    3. 	<param-value>/WEB-INF/struts-config.xml,/WEB-INF/struts-config-2.xml</param-value>
    4. 	</init-param>
    7.....

    基于struts的用户注册验证:
    1.导入struts标签库;
    1. <%@ page language="java" contentType="text/html; charset=utf-8"
    2.     pageEncoding="utf-8"%>
    3.     <%@ taglib prefix="html" uri="http://struts.apache.org/tags-html" %>
    4. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    5. <html>
    6. <head>
    7. <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    8. <title>Insert title here</title>
    9. </head>
    10. <body>
    11. <html:form action="/register.do" method="post" >
    12. 用户:<html:text property="username"></html:text><br/>
    13. 密码:<html:text property="password"></html:text><br/>
    14. 邮箱:<html:text property="email"></html:text><br/>
    15. <html:submit value="注册"></html:submit>
    16. <html:cancel value="取消"></html:cancel>
    17. </html:form>
    18. </body>
    19. </html>
    注意:这里的用户、密碼、郵箱必须在<html:form>中并且在form中有相应的字段与之对应.否则会报500错误.因为struts默认认为你的输入框等控件是要用来提交的,所以,必须写在form中且有相应的form类与之对应.而不是在你提交的时候才检测.
    2.在web.xml中添加字符编码过滤器Filter,在配置文件中设置字符编码可以使程序更加灵活,也更利于维护;
    1. 	<filter>
    2. 		<filter-name>MyFilter</filter-name>
    3. 		<filter-class>com.zky.struts.filter.MyFilter</filter-class>
    4. 		<init-param>
    5. 			<param-name>encoding</param-name>
    6. 			<param-value>utf-8</param-value>
    7. 		</init-param>
    9. 	</filter>
    10. 	<filter-mapping>
    11. 		<filter-name>MyFilter</filter-name>
    12. 		<url-pattern>/*</url-pattern>
    13. 	</filter-mapping>
    1. public class MyFilter extends HttpServlet implements Filter {
    2. 	private String encoding; 
    3. 	@Override
    4. 	public void doFilter(ServletRequest request, ServletResponse response,
    5. 			FilterChain chain) throws IOException, ServletException {
    6. 		// TODO Auto-generated method stub
    7. 		request.setCharacterEncoding(encoding);
    8.         chain.doFilter(request, response);
    9. 	}
    11. 	@Override
    12. 	public void init(FilterConfig config) throws ServletException {
    13. 		// TODO Auto-generated method stub
    14. 			encoding = config.getInitParameter("encoding");
    15. 	}
    17. }
    3.在web.xml中添加关键字过滤器SafeFilter,虽然在Action中也可以实现关键字过滤,但是在filter中实现更好;
    1. 	<filter>
    2. 		<filter-name>SafeFilter</filter-name>
    3. 		<filter-class>com.zky.struts.filter.SafeFilter</filter-class>
    4. 		<init-param>
    5. 			<param-name>keywords</param-name>
    6. 			<param-value>拉登;小明;XXX;西吧</param-value>
    7. 		</init-param>
    9. 	</filter>
    10. 	
    11. 	<filter-mapping>
    12. 		<filter-name>SafeFilter</filter-name>
    13. 		<url-pattern>/*</url-pattern>
    14. 	</filter-mapping>
    java代码:
    1. public class SafeFilter extends HttpServlet implements Filter {
    2. 	private String[] keywords;
    4. 	@Override
    5. 	public void doFilter(ServletRequest request, ServletResponse response,
    6. 			FilterChain chain) throws IOException, ServletException {
    7. 		// TODO Auto-generated method stub
    8. 		String username = (String) request.getAttribute("username");
    9. 		if (username != null) {
    10. 			for (String keyword : keywords) {
    11. 				if (keyword.equals(username)) {
    12.                     request.getRequestDispatcher("/WEN-INF/err.jsp").forward(request, response);
    13. 					return;
    14. 				}
    15. 			}
    16. 		}
    17. 		chain.doFilter(request, response);
    18. 	}
    20. 	@Override
    21. 	public void init(FilterConfig config) throws ServletException {
    22. 		// TODO Auto-generated method stub
    23. 		keywords = config.getInitParameter("keywords").split(";");
    24. 	}
    25. }
    问题:1.在web.xml文件中编辑filter的配置信息是,不小心删除了ActionServlet的部分配置文件,导致404错误;
        2.在获得用户输入的用户名是应使用request.getParameter("username");而不是request.getAttribute("username");
    导致过滤器无法使用.


    案例：文件的上传下载
    * 文件上传需要解决的几个问题:
        1.文件名重复时,后上传的文件会覆盖先上传文件的问题;
        2.中文文件名显示乱码问题;







     
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  • 原文地址：https://www.cnblogs.com/Jxiaobai/p/6618572.html
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