首先创建一个JSP和Servlet：
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>title</title>
</head>
<body>
<a href="<c:url value='/AServlet?username=张三'/>">点击这里</a>
<form action="<c:url value='/AServlet'/>" method="post">
<input type="text" name="username" value="张三"/>
<input type="submit" value="提交"/>
</form>
</body>
</html>
package svt;
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("/AServlet")
public class AServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String name = req.getParameter("username"); // 获取参数
resp.getWriter().print(name);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String name = request.getParameter("username"); // 获取参数
response.getWriter().print(name);
}
}
访问后发现，post请求和get请求得到的都是乱码：
所以就需要解决这个乱码问题；
先创建一个过滤器：
package filter;
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;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cla.AReq;
public class AFt extends HttpFilter implements Filter {
int count = 0;
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// 处理编码问题
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
System.out.println("拦截！" + count++);
HttpServletResponse res = (HttpServletResponse) response;
if (count == 5) {
response.getWriter().print("到5了！");
res.sendRedirect("/day430a/jsp/d.jsp");
// request.getRequestDispatcher("/jsp/d.jsp").forward(request, response);
} else {
chain.doFilter(request, response);
}
}
public void init(FilterConfig fConfig) throws ServletException {
System.out.println("Born!");
}
}
因为这个过滤器配置的是 /* 会过滤所有每一次请求的任意页面，所以使用它来设置编码就相当于设置了每一个次请求的页面编码。
还有一种是调包的形式，自定义类继承HttpServletRequestWapper类重写getParam()方法，将获取的参数使用String的构造方法能够将一种编码转换为另一种编码。
