Javaweb using Servlet Filter technology to rewrite the user logs on using technology to solve the Chinese garbled

Experiment 3 first jsp pages copied;

WebContent-> WEB-INF-> lib jar package below version 8.0 have to remember to copy;

Java Resources-> cn.edu.henu.bean (User.java user database operations) in the src and cn.edu.henu.util (DBConnection.java database connection operation) the two packets

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>ws_shiyan3</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>addUser.jsp</welcome-file>

　　

The use of Servlet technology to rewrite the user logs

src -> New to create a package "cn.edu.henu.servlet" -> Create a servlet class name "LoginCheckServlet" -> URL mapping is set to "/ CheckServlet"
rewrite dopost () method, the third experiment check.jsp landing authentication code can be copied

String name=request.getParameter("name");
  String pwd=request.getParameter("pwd");
  PreparedStatement pt=null;
  Connection con = null;
  User user = null;
  try { 
   //JDBC访问数据库
   con=DBConnection.openConnection();//获取数据库连接
   String sql="SELECT * from login WHERE user=? AND passwod=?";
    pt=con.prepareStatement(sql);
    pt.setString(1, name);
    pt.setString(2, pwd);
    ResultSet rs=pt.executeQuery();
    System.out.println("?????????????????????");
    if(rs.next())
    {
     response.sendRedirect("connsuccess.jsp");
    }
    else{
    response.sendRedirect("connError.jsp");
    } 
   
  } catch (SQLException e) {
   E.printStackTrace ();}

　　

You can also refer to this JSP + Servlet user's login
[Note] here User user = null; below the yellow alarm so I just started commented out, the results CheckServlet on page 404, later canceled before they can comment

There are two ways to configure the Servlet
① automatically @WebServlet ( "/ CheckServlet") LoginCheckServlet page generated
② disposed below web.xml

  <the servlet> 
    <the servlet-name> LoginCheckServlet </ the servlet-name> // create an object using the class name 
    <servlet-class> cn.edu.henu.servlet.LoginCheckServlet </ servlet-class> // servlet class created their own 
  </ servlet> 
  <-Mapping the servlet> 
    <the servlet-name> LoginCheckServlet </ servlet-name> is the actual implementation of the object // 
    <url-pattern> / CheckServlet < / url-pattern> // URL Mapping custom 
  </ servlet -mapping>

　　

Note] Oh, here name to match

 

[Note] two methods can only choose a configuration, otherwise it will error
to use technology to solve the Chinese garbled Filter

src -> new Filter (package name is "cn.edu.henu.Filter", Filter name is "EncodingFilter", MAP did not change my name EncodingFilter
then enter request.setCharacterEncoding ( "utf-8" in (under doFilter) ); to

 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
  // TODO Auto-generated method stub
  // place your code here
  request.setCharacterEncoding("utf-8");
  // pass the request along the filter chain
  chain.doFilter(request, response);
 }

　

    <filter>
    <filter-name>EncodingFilter</filter-name>
    <filter-class>cn.edu.henu.filter.EncodingFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>EncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>  //拦截所有请求
  </filter-mapping>

 

Original: https: //blog.csdn.net/wwjlovecyndi/article/details/90300255