Request 获取请求行数据
获取方法
String getMethod()
// 获取请求方式
String getContextPath()
// 获取虚拟目录
String getServletPath()
// 获取Servlet路径
String getRequestURI()
StringBuffer getRequestURL()
// 获取请求URI、URL
String getProtocol()
// 获取协议及版本
String getRemoteAddr()
// 获取客户机的IP地址
URI & URL 的说明：
- URL：统一资源定位符
- URI：统一资源标识符
如：
- 例子1
- http://localhost/stringbug/demo1 —— URL
- /stringbug/demo1 —— URI
- 例子2
- 中华人民共和国 —— URL
- 共和国 —— URI
创建一个类，继承HttpServlet类
package study.request;
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("/study/request/demo01")
public class RequestDemo01 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
}
}
String getMethod() 方法
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// String getMethod() 获取请求方式
System.out.println(req.getMethod());
}
String getContextPath() 方法
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// String getContextPath() 获取虚拟目录
System.out.println(req.getContextPath());
}
String getServletPath() 方法
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// String getServletPath() 获取Servlet路径
System.out.println(req.getServletPath());
}
String getRequestURI()、StringBuffer getRequestURL() 方法
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// String getRequestURI() 获取请求URI
// StringBuffer getRequestURL() 获取请求URL
System.out.println(req.getRequestURI());
System.out.println(req.getRequestURL());
}
String getProtocol() 方法
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// String getProtocol() 获取协议及版本
System.out.println(req.getProtocol());
}
String getRemoteAddr() 方法
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// String getRemoteAddr() 获取客户机的IP地址
System.out.println(req.getRemoteAddr());
}
创建一个html文件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Request Study</title>
</head>
<body>
<form action="/RequestAndResponse_war_exploded/study/request/demo01" method="get">
<input name="username">
<input type="submit" value="get提交">
</form>
</body>
</html>
开启服务器
-
用户访问：http://localhost:8080/RequestAndResponse_war_exploded/HelloRequest.html
-
随便输入点内容，提交，如输入：RequestTest
页面跳转到：http://localhost:8080/RequestAndResponse_war_exploded/study/request/demo01?username=RequestTest
-
获取请求方式：getMethod() 方法输出
GET -
获取虚拟目录：getContextPath() 方法输出
/RequestAndResponse_war_exploded -
获取Servlet路径：getServletPath() 方法输出
/study/request/demo01 -
获取请求URI：getRequestURI() 方法输出
/RequestAndResponse_war_exploded/study/request/demo01 -
获取请求URL：getRequestURL() 方法输出
http://localhost:8080/RequestAndResponse_war_exploded/study/request/demo01 -
获取协议及版本：getProtocol() 方法输出
HTTP/1.1 -
获取客户机的IP地址：getRemoteAddr() 方法输出
0:0:0:0:0:0:0:1
-
Request 获取请求头数据
获取方法
String getHeader(String name)
// 通过请求头的名称获取请求头的值
Enumeration<String> getHeaderNames()
// 获取所有的请求头名称
创建一个类(RequestDemo02.java)，使用这两个方法
package study.request;
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.util.Enumeration;
@WebServlet("/study/request/demo02")
public class RequestDemo02 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// 获取所有请求头名称
Enumeration<String> headerNames = req.getHeaderNames();
// Enumeration接口，功能由Iterator复制。
while (headerNames.hasMoreElements()) {
String headerName = headerNames.nextElement();
// 根据请求头名称获取请求头名称的值
String headerValue = req.getHeader(headerName);
System.out.println(headerName + " : " + headerValue);
}
}
}
开启服务器
访问：http://localhost:8080/RequestAndResponse_war_exploded/study/request/demo02
控制台输出：
自己根据请求头名字获取请求头
user-agent
获取用户访问资源链接时使用的浏览器。
package study.request;
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("/study/request/demo02")
public class RequestDemo02 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// 演示获取请求头数据：user-agent
String userAgentValue = req.getHeader("user-agent");
// 判断用户使用什么浏览器发出的请求
if (userAgentValue.contains("Chrome")) {
System.out.println("来自谷歌浏览器的访问！！！");
} else if (userAgentValue.contains("Firefox")) {
System.out.println("来自火狐浏览器的访问！！！");
} else if (userAgentValue.contains("XXX")) {
System.out.println("来自 XXX 浏览器的访问！！！");
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
}
}
谷歌浏览器访问：http://localhost:8080/RequestAndResponse_war_exploded/study/request/demo02
控制台输出：
来自谷歌浏览器的访问！！！
referer
获取用户跳转到目的页面之前的那个页面的URL
package study.request;
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("/study/request/demo02")
public class RequestDemo02 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// 演示获取请求头数据：referer
String refererValue = req.getHeader("referer");
System.out.println(refererValue);
if (refererValue.contains("/RequestAndResponse_war_exploded")) {
System.out.println("可以正常访问");
} else {
System.out.println("不可以正常访问");
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
}
}
浏览器访问：http://localhost:8080/RequestAndResponse_war_exploded/HelloRequest02.html
点击看电影，页面跳转到：http://localhost:8080/RequestAndResponse_war_exploded/study/request/demo02?View+Name=唐人街探案3
控制台输出：
http://localhost:8080/RequestAndResponse_war_exploded/HelloRequest02.html
可以正常访问
假如不是从 /RequestAndResponse_war_exploded 资源链接中跳转过来的话，那么，控制台会输出：不可以正常访问
-
也可以更改上例中的部分内容，是的部分输出在页面上：
// 将这部分内容修改 System.out.println("可以正常访问"); System.out.println("不可以正常访问");// 修改为 System.out.println("可以正常访问"); resp.setContentType("text/html;charset=utf-8"); resp.getWriter().write("你可以看电影～～～"); System.out.println("不可以正常访问"); resp.setContentType("text/html;charset=utf-8"); resp.getWriter().write("你不可以看电影～～～"); -
从
/RequestAndResponse_war_exploded资源链接中跳转过来，控制台输出：http://localhost:8080/RequestAndResponse_war_exploded/HelloRequest02.html 可以正常访问点击
看电影，页面跳转到：http://localhost:8080/RequestAndResponse_war_exploded/study/request/demo02?View+Name=唐人街探案3页面内容如下：
Request 获取请求体的数据
步骤
- 获取流对象
BufferedReader getReader()：获取字符输入流，只能操作字符数据ServletInputStream getInputStream()：获取字节输入流，可以操作所有类型数据
- 再从流对象中拿数据
简单实现
-
创建一个demo.java：RequestDemo03.java
package study.request; 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.BufferedReader; import java.io.IOException; @WebServlet("/study/request/demo03") public class RequestDemo03 extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // 获取请求消息体 // 1. 获取字符流 BufferedReader reqReader = req.getReader(); String line; while ((line = reqReader.readLine()) != null) { System.out.println(line); } } } -
创建一个html文件：login.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>用户登录</title> </head> <body> <form action="/RequestAndResponse_war_exploded/study/request/demo03" method="post"> <input type="email" name="userEmail" placeholder="请输入您的邮箱"><br> <input type="password" name="userPassword" placeholder="请输入您的密码"><br> <input type="submit" value="登录"> </form> </body> </html> -
启动服务器，浏览器访问：http://localhost:8080/RequestAndResponse_war_exploded/login.html
-
点击登录，页面跳转到：http://localhost:8080/RequestAndResponse_war_exploded/study/request/demo03
控制台输出：
userEmail=stringbug%40icloud.com&userPassword=123456浏览器页面内容：
参考文献
- HttpServletRequest获取客户端所有参数
- [JavaEE-HttpServletRequest总结](