BaseController  層 優化程式碼

 1 package com.seecen.controller;
 2 
 3 import com.seecen.service.StudentService;
 4 import org.springframework.web.context.WebApplicationContext;
 5 import org.springframework.web.context.support.WebApplicationContextUtils;
 6 
 7 import javax.servlet.ServletConfig;
 8 import
 
 javax.servlet.ServletException;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 import java.io.IOException;
13 import java.io.PrintWriter;
14 import java.io.UnsupportedEncodingException;
15 
16 /**
17  * @program: springWeb
 
18  * @description:
19  *  所有 controller 的基類
20  * @author: lan
21  * @create: 2022-05-19 16:24
22  * @version:1.0
23  **/
24 public class BaseController extends HttpServlet {
25 
26     public StudentService studentService;
27 
28     @Override
29     public void init(ServletConfig config) throws ServletException {
 
30         // 通過 web 程式獲取 IOC 容器
31         WebApplicationContext wac = WebApplicationContextUtils
32                 .getWebApplicationContext
33                         (config.getServletContext());
34         // 從 IOC 容器中取出 StudentService 例項
35         studentService = wac.getBean(StudentService.class);
36     }
37 
38 
39     /**
40      * 自定義的 servlet 初始設定
41      * @param req
42      * @param resp
43      * @throws UnsupportedEncodingException
44      */
45     public void defaultSet(HttpServletRequest req, HttpServletResponse resp) throws UnsupportedEncodingException {
46         req.setCharacterEncoding("UTF-8");
47         resp.setCharacterEncoding("UTF-8");
48         // 設定允許其他非同源訪問，Access-Control-Allow-Origin
49         resp.setHeader("Access-Control-Allow-Origin", "*");
50 
51     }
52 
53 
54     /**
55      * 將指定的內容響應至頁面
56      * @param resp
57      * @param content
58      * @throws IOException
59      */
60     public void printHtml(HttpServletResponse resp,String content) throws IOException {
61         PrintWriter writer = resp.getWriter();
62         writer.print(content);
63         writer.close();
64     }
65 
66 
67 }

findAllController

 1 package com.seecen.controller;
 2 
 3 import com.alibaba.fastjson.JSONArray;
 4 import com.seecen.pojo.Student;
 5 import com.seecen.service.StudentService;
 6 import org.springframework.beans.factory.annotation.Autowired;
 7 import org.springframework.stereotype.Controller;
 8 import org.springframework.web.context.WebApplicationContext;
 9 import org.springframework.web.context.support.SpringBeanAutowiringSupport;
10 import org.springframework.web.context.support.WebApplicationContextUtils;
11 
12 import javax.servlet.ServletConfig;
13 import javax.servlet.ServletException;
14 import javax.servlet.annotation.WebServlet;
15 import javax.servlet.http.HttpServlet;
16 import javax.servlet.http.HttpServletRequest;
17 import javax.servlet.http.HttpServletResponse;
18 import java.io.IOException;
19 import java.io.PrintWriter;
20 import java.util.List;
21 
22 /**
23  * @program: springWeb
24  * @description:
25  *  用於接收使用者發起的  /findAll.do 請求的 servlet
26  * @author: lan
27  * @create: 2022-05-19 15:13
28  * @version:1.0
29  **/
30 @WebServlet("/findAll.do")
31 public class FindAllController extends BaseController {
32 
33     @Override
34     protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
35         System.out.println("接收到了 /findAll.do 請求");
36         // 1，設定編碼格式，設定跨域
37         defaultSet(req, resp);
38 
39         // 2，獲取傳遞引數，呼叫 service 層
40         System.out.println(studentService);
41         List<Student> list = studentService.findAll();
42 
43         // 3，通過 resp 將 json 響應至頁面
44         printHtml(resp, JSONArray.toJSONString(list));
45     }
46 
47 }