一.直接上代码
1.1写一个GET和POST代码分别解决中文乱码问题
注意:我们需要了解一个知识点,Tomcat7和Tomcat8之间的不同点,Tomcat8在Get请求中不会产生中文乱码问题,而在Tomcat7的GET请求中会产生中文乱码, Tomcat7和Tomcat8的Post请求都会产生中文乱码,在Tomcat官方文档中提到了Tomcat7和Tomcat8在编码过程中有不同,tomcat7用得是ISO-8859-1编码方式,而Tomcat用的则是"UTF-8"编码格式
<%@ 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>登录</title> </head> <body> --------------GET请求--------------<br> <form action="${pageContext.request.contextPath}/LoginServlet" method="get"> 用户名:<input type="text" name="username"><br> 密码:<input type="password" name="password"><br> <input type="submit" value="登录"> </form> --------------POST请求--------------<br> <form action="${pageContext.request.contextPath}/LoginServlet" method="post"> 用户名:<input type="text" name="username"><br> 密码:<input type="password" name="password"><br> <input type="submit" value="登录"> </form> </body> </html>
1.2Servlet代码
package web_servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//response.setHeader("content-type","text/html;charset=utf-8");
String vString=request.getParameterMap().get("username")[0];
System.out.println("dopost里面的request"+request);
String username=request.getParameter("username");
String password=request.getParameter("password");
System.out.println(username);
System.out.println(password);
if("张三".equals(username)&"123".equals(password)){
response.getWriter().write("登录成功");
response.getWriter().write(username+password);
}
else{
response.getWriter().write("登录失败");
}
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username=request.getParameter("username");
String password=request.getParameter("password");
System.out.println(username);
System.out.println(password);
if("张三".equals(username)&"123".equals(password)){
response.getWriter().write("登录成功");
response.getWriter().write(username+password);
}
else{
response.getWriter().write("登录失败");
}
}
}
1.3过滤器的配置
package web_Filter; import java.io.IOException; import java.util.Map; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import javax.servlet.http.HttpServletResponse; public class MyEncodingFilter implements Filter{ @Override public void init(FilterConfig arg0) throws ServletException { // TODO Auto-generated method stub System.out.println("过滤器的初始化"); } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { // TODO Auto-generated method stub //1.设置编码格式为UTF-8 System.out.println("dofilter里面的request"+request); HttpServletResponse response2=(HttpServletResponse)response; response2.setHeader("content-type", "text/html;charset=utf-8"); //request.setCharacterEncoding("UTF-8"); //2.如果编码格式为UTF-8则放行 myRequest myRequest=new myRequest((HttpServletRequest)request); chain.doFilter(myRequest, response); } @Override public void destroy() { // TODO Auto-generated method stub System.out.println("过滤器的销毁"); } } /** * Wrapper包装类,内部有个真实对象的引用 * @author maskpd * */ class myRequest extends HttpServletRequestWrapper{ private HttpServletRequest request; public myRequest(HttpServletRequest request) { super(request); this.request=request; } @Override public String getParameter(String name) { // TODO Auto-generated method stub return null; } @Override public Map<String, String[]> getParameterMap() { // TODO Auto-generated method stub return super.getParameterMap(); } }
1.4配置过滤器
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1"> <display-name>2020-1-20webproject</display-name> <!-- 编码过滤器 --> <filter> <filter-name>MyEncodingFilter</filter-name> <filter-class>web_Filter.MyEncodingFilter</filter-class> </filter> <filter-mapping> <filter-name>MyEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
二.OK了