页面跳转之转发和重定向+Servlet中文乱码问题
页面跳转之转发和重定向+Servlet中文乱码问题
一、页面跳转
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<welcome-file-list>
<welcome-file>welcome.htmlwelcome-file>
welcome-file-list>
web-app>
1.页面跳页面
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h1>知识点：跳转h1>
<hr/>
<h3>页面跳页面h3>
<a href="page01.html">跳转到Page01页面a><br/>
<input type="button" value="跳转到Page01页面" onclick="fun01()"/><br/>
<form action="page01.html" method="post" style="border:red 1px solid">
账号：<input type="text" name="username" placeholder="请输入账号"><br/>
密码：<input type="password" name="password" placeholder="请输入密码"><br/>
<input type="submit" value="提交按钮"/>
form>
<script type="text/javascript">
function fun01() {
location = "page01.html";
}
script>
body>
html>
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h1>Page01页面h1>
body>
html>
2.页面跳Servlet
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h3>页面跳Servleth3>
<a href="Servlet01?username=aaa&password=123123">跳转到Servlet01a><br/>
<input type="button" value="跳转到Servlet01" onclick="fun02()"/><br/>
<form action="Servlet01" method="post" style="border:red 1px solid">
账号：<input type="text" name="username" placeholder="请输入账号"><br/>
密码：<input type="password" name="password" placeholder="请输入密码"><br/>
<input type="submit" value="提交按钮"/>
form>
<script type="text/javascript">
function fun02() {
location = "Servlet01?username=bbb&password=123123"
}
script>
body>
html>
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/Servlet01")
public class Servlet01 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
System.out.println("Servlet01接收到客户的请求了：" + username + "--" + password);
}
}
3.Servlet跳Servlet
1.转发
request.getRequestDispatcher(“页面.html”).forward(request, response);
2.重定向
response.sendRedirect(“页面.html”);
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h3>Servlet跳Servleth3>
<a href="Servlet02">向Servlet02发送请求 -- 转发a><br/>
<a href="Servlet03">向Servlet03发送请求 -- 重定向a>
<hr/>
body>
html>
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/Servlet02")
public class Servlet02 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset:UTF-8");
//转发
request.getRequestDispatcher("OtherServlet").forward(request,response);
}
}
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/OtherServlet")
public class OtherServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
System.out.println("OtherServlet接受到请求了...");
}
}
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/Servlet03")
public class Servlet03 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
//重定向
response.sendRedirect("OtherServlet");
}
}
4.Servlet跳页面
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h3>Servlet跳页面h3>
<a href="Servlet04">向Servlet04发送请求 -- 转发a><br/>
<a href="Servlet05">向Servlet05发送请求 -- 重定向a>
body>
html>
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/Servlet04")
public class Servlet04 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
//转发
request.getRequestDispatcher("page02.html").forward(request,response);
}
}
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h1>Page02页面h1>
body>
html>
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet( "/Servlet05")
public class Servlet05 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
//重定向
response.sendRedirect("page02.html");
}
}
二、转发与重定向的区别
区别1：转发是发送1次请求，重定向是发送2次请求
区别2：转发可以访问WEB-INF下的页面（受保护的页面）,重定向不可以访问
区别3：重定向可以访问外部服务器，转发不可以访问
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<a href="Servlet06">向Servlet06发送请求 -- 做实验a>
body>
html>
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/Servlet06")
public class Servlet06 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
//跳转普通页面(web文件夹下的页面)
//转发 -- yes
//request.getRequestDispatcher("page02.html").forward(request,response);
//重定向 -- yes
//response.sendRedirect("page02.html");
//跳转受保护的页面(WEB-INF文件夹下的页面)
//注意：WEB-INF文件夹下的页面只能服务器内部访问
//转发 -- yes
//request.getRequestDispatcher("WEB-INF/page03.html").forward(request,response);
//重定向 -- no（原因：客户端不能直接访问WEB-INF文件夹下的页面）
//response.sendRedirect("WEB-INF/page03.html");
//跳转外部服务器
//注意：当前服务器不能访问外部服务器
//转发 -- no
//request.getRequestDispatcher("http://www.baidu.com").forward(request,response);
//重定向 -- yes(原因：重定向是发送两次请求，告诉客户端去访问外部服务器)
response.sendRedirect("http://www.baidu.com");
}
}
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h1>page03页面h1>
body>
html>
三、Servlet中文乱码问题
1.出现原因
前端后端编码不一致
浏览器默认使用UTF-8码表进行编码 ，Servlet使用ISO-8859-1码表进行编码
传输和接收方编码不一致导致乱码的产生
2.Request乱码
Request请求分为post和get，分别有不同的解决方案
1.Request乱码 - POST请求
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//给请求中的参数设置编码格式
request.setCharacterEncoding("UTF-8");
String parameter1 = request.getParameter("parameter1");
String parameter2 = request.getParameter("parameter2");
System.out.println(parameter1);
System.out.println(parameter2);
}
作用：设置从 request 中取得的值,用来指定对浏览器发送来的数据进行重新编码时，使用的编码。
使用注意事项：
- 在执行 setCharacterEncoding()之前，不能执行任何 getParameter()操作
- 通过 setCharacterEncoding 设置的编码方式只对 POST 方式提交的表单有效，对 GET 方式无效
2.Request乱码 - GET请求(Tomcat7.X版本)
解决方案1
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String parameter1 = request.getParameter("parameter1");
parameter1 = new String(parameter1.getBytes("ISO-8859-1"),"UTF-8");
String parameter2 = request.getParameter("parameter2");
parameter2 = new String(parameter2.getBytes("ISO-8859-1"),"UTF-8");
System.out.println(parameter1);
System.out.println(parameter2);
}
解决方案2
在Tomcat根目录/conf/server.xml中设置编码格式
<Connector URIEncoding="UTF-8" port="8080" protocol="HTTP/1.1"
connectionTimeout="20000" redirectPort="8443"
/>
那么在启动服务器的时候就会读取到URIEncoding的属性配置,然后再调用自己的一个setURIEncoding方法完成设置,形参的值为我们设置的UTF-8
protected String URIEncoding = null;
public void setURIEncoding(String URIEncoding) {
this.URIEncoding = URIEncoding;
setProperty("URIEncoding", URIEncoding);
}
3.Request乱码 - GET请求(Tomcat8.X版本)
Tomcat8.x的服务器在接收GET请求时,即使参数中有中文,也不会出现乱码，作者在底层设计上的一些改动
Tomcat的连接器组件(Connector) ，Connector是Tomcat中的一个重要的组件，它负责监听Tomcat收到的请求信息，并将这些请求信息传递给Servlet规范中所定义的Request，然后将转换后的请求交给Engine组件
去处理，最后将Engine返回的Response返回给客户端 。源码中我们可以看到, URIEncoding的默认值为UTF-8,所以在Tomcat8.x中,即使GET请求包含了中文的数据,也不会出现乱码了
public class Connector extends LifecycleMBeanBase {
private Charset uriCharset = StandardCharsets.UTF_8;
//查询Tomcat根目录/conf/catalina.properties配置文件中的属性
public static final boolean RECYCLE_FACADES =
Boolean.parseBoolean(System.getProperty("org.apache.catalina.connector.RECYCLE_FACADES", "false"));
public Connector() {
this(null);
}
public Connector(String protocol) {
setProtocol(protocol);
ProtocolHandler p = null;
try {
Class<?> clazz = Class.forName(protocolHandlerClassName);
p = (ProtocolHandler) clazz.getConstructor().newInstance();
} catch (Exception e) {
log.error(sm.getString(
"coyoteConnector.protocolHandlerInstantiationFailed"), e);
} finally {
this.protocolHandler = p;
}
if (Globals.STRICT_SERVLET_COMPLIANCE) {
uriCharset = StandardCharsets.ISO_8859_1;
} else {
uriCharset = StandardCharsets.UTF_8;
}
}
}
4.Response乱码
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置响应内容的编码格式
response.setContentType("text/html;charset=UTF-8");
response.getWriter().println("千锋吴彦祖");
}
5.跳转到中文页面路径乱码
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.sendRedirect(URLEncoder.encode("详情页面.html", "UTF-8"));
}
四、跳转到中文名的页面
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h3>知识点：跳转到中文名的页面h3>
<a href="Servlet07">跳转到中文名的页面a>
body>
html>
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URLEncoder;
@WebServlet( "/Servlet07")
public class Servlet07 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
//注意：中文名的网页一定要设置编码格式
response.sendRedirect(URLEncoder.encode("用良心做教育.html","UTF-8"));
}
}
DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h1>用真心待人h1>
body>
html>