一、介绍
- 该对象存储了请求用户的信息。
- 一般用于获取参数、请求头数据、Cookie、Session等等。
- Request对象是一个域对象。
- 可以向域对象Request中存取数据。
二、项目测试(常用API)
public class MyServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取请求方法
String method = req.getMethod();
System.out.println(method);
//获取客户端地址
String remoteAddr = req.getRemoteAddr();
System.out.println(remoteAddr);
//获取请求头信息
String header = req.getHeader("User-Agent");
System.out.println(header);
//获取请求URL
StringBuffer requestURL = req.getRequestURL();
System.out.println(requestURL);
}
}
三、项目测试(获取表单参数)
(1)创建html页面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<form action="/test01/test01" method="get">
<div>用户名:<input name="username" type="text"></div>
<div>
爱好:<input type="checkbox" name="hobby" value="sing">唱
<input type="checkbox" name="hobby" value="dance">跳
</div>
<div><input type="submit" value="提交"></div>
</form>
</body>
</html>
(2)MyServlet类继承HttpServlet类
public class MyServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String username = req.getParameter("username");
System.out.println(username);
String[] hobbies = req.getParameterValues("hobby");
System.out.println(Arrays.toString(hobbies));
System.out.println("===========================================");
//另一种方式
Map<String, String[]> parameterMap = req.getParameterMap();
String[] strings1 = parameterMap.get("username");
System.out.println(Arrays.toString(strings1));
String[] strings2 = parameterMap.get("hobby");
System.out.println(Arrays.toString(strings2));
}
}
(3)编写web.xml文件,配置Servlet
<?xml version="1.0" encoding="UTF-8"?>
<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">
<servlet>
<servlet-name>MyServlet</servlet-name>
<servlet-class>com.wsh.servlet.MyServlet</servlet-class>
<!--load-on-startup的值大于等于0时,Servlet在Tomcat启动时初始化-->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>MyServlet</servlet-name>
<url-pattern>/test01</url-pattern>
</servlet-mapping>
</web-app>
(4)配置Tomcat中的项目上下文路径
(5)运行
三、Request对象请求参数的中文乱码处理
(1)Get方法,Tomcat已解决,不会产生乱码。
(2)Post方法,需要在获取参数前设置字符集,否则设置失效。
public class MyServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
String username = req.getParameter("username");
System.out.println(username);
}
}