程序源代码下载

Get请求与Post请求

请求方法

Post常用于安全性要求较高的功能或者服务器“写”操作

  • 如：用户注册、登录、更新个人资料等

    请求参数的发送与接收

  • 请求参数是指浏览器通过请求向Tomcat提交的数据

  • 请求参数通常是用户输入的数据，待Servlet进行处理
  • 参数名1=值1&参数名2=值2&参数名n=值n=…

    Servlet接收Get参数

    ```java package com.ouchaochao;

import javax.servlet.; import javax.servlet.http.; import javax.servlet.annotation.*; import java.io.IOException; import java.io.PrintWriter;

@WebServlet(name = “sampleServlet”, value = “/sampleServlet”) public class sampleServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String methodName = request.getMethod(); String name = request.getParameter(“name”); String mobile = request.getParameter(“mobile”); String sex = request.getParameter(“sex”); String[] specs = request.getParameterValues(“spec”);

  1.     PrintWriter out = response.getWriter();//向浏览器输出的数据流
  2.     out.println("<h1>method:" + methodName + "</h1>");
  3.     out.println("<h1>name:" + name + "</h1>");
  4.     out.println("<h1>mobile:" + mobile + "</h1>");
  5.     out.println("<h1>sex:" + sex + "</h1>");
  6.     for (int i = 0; i < specs.length; i++) {
  7.         out.println("<h2>spec:" + specs[i] + "</h2>");
  8.     }
  9. }

}

  1. <a name="HC203"></a>
  2. #### web.xml配置
  3. ```java
  4. <?xml version="1.0" encoding="UTF-8"?>
  5. <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  6.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  7.          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
  8.          version="4.0">
  9.     <servlet>
  10.         <servlet-name>hello</servlet-name>
  11.         <servlet-class>com.ouchaochao.helloServlet</servlet-class>
  12.     </servlet>
  13.     <servlet>
  14.         <servlet-name>sample</servlet-name>
  15.         <servlet-class>com.ouchaochao.sampleServlet</servlet-class>
  16.     </servlet>
  17.     <servlet-mapping>
  18.         <servlet-name>hello</servlet-name>
  19.         <url-pattern>/hello</url-pattern>
  20.     </servlet-mapping>
  21.     <servlet-mapping>
  22.         <servlet-name>sample</servlet-name>
  23.         <url-pattern>/sample</url-pattern>
  24.     </servlet-mapping>
  27. </web-app>

student.html配置

  1. <!DOCTYPE html>
  2. <html>
  3. <head>
  4. <meta charset="UTF-8">
  5. <title>学员信息登记表</title>
  6. </head>
  7. <body>
  8.     <h1>学员信息登记表</h1>
  9.     <form action="/testServlet/sample" method="get" >
  10.         姓名：<input name="name"/>
  11.         <br/>
  12.         电话：<input name="mobile"/>
  13.         <br/>
  14.         性别：
  15.         <select name="sex" style="width:100px;padding:5px;">
  16.             <option value="male" >男</option>
  17.             <option value="female">女</option>
  18.         </select>
  19.         <br/>
  20.         特长:
  21.         <input type="checkbox" name="spec" value="English"/>英语
  22.         <input type="checkbox" name="spec" value="Program"/>编程
  23.         <input type="checkbox" name="spec" value="Speech"/>演讲
  24.         <input type="checkbox" name="spec" value="Swimming"/>游泳
  25.         <br/>
  26.         <input type="submit" value="提交">
  27.         <br/>
  28.     </form>
  29. </body>
  30. </html>

结果展示

image.png
点击提交后页面跳转结果如下：
image.png

Servlet接受Post参数

  1. package com.ouchaochao;
  3. import javax.servlet.*;
  4. import javax.servlet.http.*;
  5. import javax.servlet.annotation.*;
  6. import java.io.IOException;
  7. import java.io.PrintWriter;
  9. @WebServlet(name = "sampleServlet", value = "/sampleServlet")
  10. public class sampleServlet extends HttpServlet {
  11.     @Override
  12.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  13.         String methodName = request.getMethod();
  14.         String name = request.getParameter("name");
  15.         String mobile = request.getParameter("mobile");
  16.         String sex = request.getParameter("sex");
  17.         String[] specs = request.getParameterValues("spec");
  19.         PrintWriter out = response.getWriter();//向浏览器输出的数据流
  20.         out.println("<h1>method:" + methodName + "</h1>");
  21.         out.println("<h1>name:" + name + "</h1>");
  22.         out.println("<h1>mobile:" + mobile + "</h1>");
  23.         out.println("<h1>sex:" + sex + "</h1>");
  24.         for (int i = 0; i < specs.length; i++) {
  25.             out.println("<h2>spec:" + specs[i] + "</h2>");
  26.         }
  27.     }
  28. }

web.xml配置

与Get的XML相同

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  3.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
  5.          version="4.0">
  6.     <servlet>
  7.         <servlet-name>hello</servlet-name>
  8.         <servlet-class>com.ouchaochao.helloServlet</servlet-class>
  9.     </servlet>
  10.     <servlet>
  11.         <servlet-name>sample</servlet-name>
  12.         <servlet-class>com.ouchaochao.sampleServlet</servlet-class>
  13.     </servlet>
  14.     <servlet-mapping>
  15.         <servlet-name>hello</servlet-name>
  16.         <url-pattern>/hello</url-pattern>
  17.     </servlet-mapping>
  18.     <servlet-mapping>
  19.         <servlet-name>sample</servlet-name>
  20.         <url-pattern>/sample</url-pattern>
  21.     </servlet-mapping>
  22. </web-app>

student.html配置

修改了 

  1. <!DOCTYPE html>
  2. <html>
  3. <head>
  4. <meta charset="UTF-8">
  5. <title>学员信息登记表</title>
  6. </head>
  7. <body>
  8.     <h1>学员信息登记表</h1>
  9.     <form action="/testServlet/sample" method="post" >
  10.         姓名：<input name="name"/>
  11.         <br/>
  12.         电话：<input name="mobile"/>
  13.         <br/>
  14.         性别：
  15.         <select name="sex" style="width:100px;padding:5px;">
  16.             <option value="male" >男</option>
  17.             <option value="female">女</option>
  18.         </select>
  19.         <br/>
  20.         特长:
  21.         <input type="checkbox" name="spec" value="English"/>英语
  22.         <input type="checkbox" name="spec" value="Program"/>编程
  23.         <input type="checkbox" name="spec" value="Speech"/>演讲
  24.         <input type="checkbox" name="spec" value="Swimming"/>游泳
  25.         <br/>
  26.         <input type="submit" value="提交">
  27.         <br/>
  28.     </form>
  29. </body>
  30. </html>

结果展示

image.png
点击提交后页面跳转结果如下：
image.png

使用注解配置Servlet

可能有同学注意到了，在Servlet中有句注解，长的就像下面这个样子

@WebServlet(name = “sampleServlet”, value = “/sampleServlet”)

当在Servlet中写了有注解的情况下，我们不配置XML，也可以达到访问的效果，例如：

  1. package com.ouchaochao;
  3. import javax.servlet.*;
  4. import javax.servlet.http.*;
  5. import javax.servlet.annotation.*;
  6. import java.io.IOException;
  8. @WebServlet(name = "Anno", value = "/Anno")
  9. public class Anno extends HttpServlet {
  10.     @Override
  11.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  12.         response.getWriter().println("I am annotation");
  13.     }
  14. }

结果如下：
image.png

注

  • 注解简化了Web应用程序的配置过程
  • 使用注解配置了Servlet以后，web.xml文件中就不可以再配置相同访问的url，否则会报错；但是可以针对同一个Servlet再指定一个不同的访问URL