Servlet

1.使用注解方式配置

这种方法不与web.xml冲突。

@WebServlet()注解常用解释：

Servlet - 图1

例：

  1. package com.example.webprojet;
  3. import com.sun.org.apache.xalan.internal.xsltc.cmdline.getopt.GetOpt;
  5. import javax.servlet.ServletException;
  6. import javax.servlet.annotation.WebServlet;
  7. import javax.servlet.http.HttpServlet;
  8. import javax.servlet.http.HttpServletRequest;
  9. import javax.servlet.http.HttpServletResponse;
  10. import java.io.IOException;
  12. /**
  13.  * @author Zhtao
  14.  * @date 2022/2/25 19:35
  15.  */
  16. @WebServlet(value = {"/bs","/bss"})
  17. public class BasicServlet extends HttpServlet {
  18.     @Override
  19.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  20.         System.out.println("这是get");
  21.     }
  23.     @Override
  24.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  25.         System.out.println("这是post");
  26.     }
  27. }

此时访问/bs和/bss都可以。

2.request对象

1.request主要方法

方法名 说明
String getParameter(String name) 根据表单组件名称获取提交数据
void setCharacterEncoding(String charset) 指定每个请求的编码

2.request应用

1.Get()请求

  1. package com.qf.servlet2;
  3. import com.sun.javaws.HtmlOptions;
  5. import javax.servlet.ServletException;
  6. import javax.servlet.annotation.WebServlet;
  7. import javax.servlet.http.HttpServlet;
  8. import javax.servlet.http.HttpServletRequest;
  9. import javax.servlet.http.HttpServletResponse;
  10. import java.io.IOException;
  11. import java.security.SecureRandom;
  13. /**
  14.  * @author Zhtao
  15.  * @date 2022/2/25 19:56
  16.  */
  17. @WebServlet(value = "/rs")
  18. public class RegisterServlet extends HttpServlet {
  19. //    1.获取用户请求发送的数据
  20.     @Override
  21.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  22.         String username = req.getParameter("username");
  23.         String password = req.getParameter("password");
  24.         System.out.println("用户提交的数据:" + username + "\t" + password);
  25.     }
  26. }

Servlet - 图2

Servlet - 图3

Servlet - 图4

2.Post()请求

  1. package com.qf.servlet2;
  3. import com.sun.javaws.HtmlOptions;
  5. import javax.servlet.ServletException;
  6. import javax.servlet.annotation.WebServlet;
  7. import javax.servlet.http.HttpServlet;
  8. import javax.servlet.http.HttpServletRequest;
  9. import javax.servlet.http.HttpServletResponse;
  10. import java.io.IOException;
  11. import java.security.SecureRandom;
  13. /**
  14.  * @author Zhtao
  15.  * @date 2022/2/25 19:56
  16.  */
  17. @WebServlet(value = "/rs")
  18. public class RegisterServlet extends HttpServlet {
  19. //    1.获取用户请求发送的数据
  21.     @Override
  22.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  23.         String username = req.getParameter("username");
  24.         String password = req.getParameter("password");
  25.         System.out.println("用户提交的数据:" + username + "\t" + password);
  26.     }
  27. }

Servlet - 图5

Servlet - 图6

3.解决中文乱码

req.setCharacterEncoding(“UTF-8”);

  1. package com.qf.servlet2;
  3. import com.sun.javaws.HtmlOptions;
  5. import javax.servlet.ServletException;
  6. import javax.servlet.annotation.WebServlet;
  7. import javax.servlet.http.HttpServlet;
  8. import javax.servlet.http.HttpServletRequest;
  9. import javax.servlet.http.HttpServletResponse;
  10. import java.io.IOException;
  11. import java.security.SecureRandom;
  13. /**
  14.  * @author Zhtao
  15.  * @date 2022/2/25 19:56
  16.  */
  17. @WebServlet(value = "/rs")
  18. public class RegisterServlet extends HttpServlet {
  21.     @Override
  22.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  23. //    对request请求对象设置统一编码
  24.         req.setCharacterEncoding("UTF-8");
  25. //    1.获取用户请求发送的数据
  26.         String username = req.getParameter("username");
  27.         String password = req.getParameter("password");
  28.         System.out.println("用户提交的数据:" + username + "\t" + password);
  29.     }
  30. }

3.response响应数据

1.response主要方法

方法名称 作用
setHeader(name,value) 设置响应信息头
setContenType(String) 设置响应文件数据、响应式的编码格式
setCharacterEncoding(Sting) 设置服务端响应内容编码格式
getWriter() 获取字符输出流

例:用户注册后，返回注册成功！

  1. package com.qf.servlet2;
  3. import com.sun.javaws.HtmlOptions;
  5. import javax.servlet.ServletException;
  6. import javax.servlet.annotation.WebServlet;
  7. import javax.servlet.http.HttpServlet;
  8. import javax.servlet.http.HttpServletRequest;
  9. import javax.servlet.http.HttpServletResponse;
  10. import java.io.IOException;
  11. import java.io.PrintWriter;
  12. import java.security.SecureRandom;
  14. /**
  15.  * @author Zhtao
  16.  * @date 2022/2/25 19:56
  17.  */
  18. @WebServlet(value = "/rs")
  19. public class RegisterServlet extends HttpServlet {
  22.     @Override
  23.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  24.         //    对request请求对象设置统一编码
  25.         req.setCharacterEncoding("UTF-8");
  26. //    1.获取用户请求发送的数据
  27.         String username = req.getParameter("username");
  28.         String password = req.getParameter("password");
  29.         System.out.println("用户提交的数据:" + username + "\t" + password);
  30. //    2.响应数据给客户端
  31.         PrintWriter printWriter = resp.getWriter();
  32.         printWriter.println("Register Success!");
  33.     }
  34. }

Servlet - 图7

2.解决返回中文乱码

方法1（不推荐）：

  1. resp.setCharacterEncoding("utf-8"); // 设置服务器端编码格式
  2. resp.setHeader("Content-Type","text/html;charset=utf-8");   // 设置客户端编码方式

方法2：

放到PrintWriter printWriter = resp.getWriter();后面

  1. resp.setContentType("text/html;charset=UTF-8");