springboot整合web开发（整合servlet、filter、listener、访问静态、文件上传）

整合servlet

1.继承HttpServlet

2.添加@WebServlet注解

@WebServlet(name="FirstServlet",urlPatterns="/firstServlet")

public class FirstServlet extends HttpServlet{

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        System.out.println("doGet");

        // 解决json中文乱码

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

        resp.setCharacterEncoding("UTF-8");

        PrintWriter out = resp.getWriter();

        String str ="{\"name\":\"欧女士\",\"sex\":\"30岁啦\"}";

        out.println(str);

        out.flush();

        out.close();

    }

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        System.out.println("doPost");

    }

}

3.在启动类添加@ServletComponentScan

@SpringBootApplication

@ServletComponentScan

public class AppMain {

    public static void main(String[] args) {

        SpringApplication.run(AppMain.class, args);

    }

}

浏览器访问

整合filter

1.实现Filter

2.添加注解 @WebFilter(filterName=“FirstFilter”,urlPatterns={".do",".jsp","/first"})
新建FirstFilter过滤器

@WebFilter(filterName="FirstFilter",urlPatterns={"*.xx","/firstFilter"})

public class FirstFilter implements Filter{

    @Override

    public void destroy() {

    }

    @Override

    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)

            throws IOException, ServletException {

        System.out.println("==="+arg0.getParameter("sign"));

/*        if("no".equals(arg0.getParameter("sign"))){

            return;

        }*/

        arg2.doFilter(arg0, arg1);

    }

    @Override

    public void init(FilterConfig arg0) throws ServletException {

    }

}

新建HelloController

@RestController

public class HelloController {

    @GetMapping("/firstFilter")

    public String firstFilter(String sign){

        System.out.println("---"+sign);

        return "firstFilter";

    }

}

3.启动类添加 @ServletComponentScan

浏览器访问

整合listener

1.实现 ServletContextListener

2.添加WebListenter注解
新建FirstListener 监听器

@WebListener

public class FirstListener implements ServletContextListener{

    @Override

    public void contextDestroyed(ServletContextEvent arg0) {

    }

    @Override

    public void contextInitialized(ServletContextEvent arg0) {

        System.out.println("---contextInitialized---");

    }

}

3.启动类添加 @ServletComponentScan

访问静态资源

访问静态资源springboot有两种方式

第一种

在/resources下建static文件夹，名字一定要命名为static。如图

新建list.html文件

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>用户列表</title>

</head>

<body>

用户列表界面<br/>

<img alt="图片" src="/image/3.jpg">

</body>

</html>

浏览器访问，如图

第二种

在src/main/webapp ，在main下建文件夹webapp,如图

文件上传

1.新建fileUpload.html

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>文件上传</title>

</head>

<body>

  <form action="/helloFileUpdate" method="post" enctype="multipart/form-data">

      上传文件：<input type="file" name="filename"><br/>

      <input type="submit" value="提交">

  </form>

</body>

</html>

2.新建HelloController

@RestController

public class HelloController {

    @RequestMapping("/helloFileUpdate")

    public Object helloFileUpdate(MultipartFile filename){

        System.out.println("文件名称"+filename.getOriginalFilename());

        Map<String,Object> retMap = new HashMap<String,Object>();

        try {

            filename.transferTo(new File("D:\\upload\\"+filename.getOriginalFilename()));

            retMap.put("sign", "ok");

            retMap.put("mes", "文件上传成功");

        } catch (IllegalStateException | IOException e) {

            e.printStackTrace();

            retMap.put("sign", "ok");

            retMap.put("mes", "文件上传失败");

        }

        return retMap;

    }

}

3.配置上传文件大小等

编辑application.yml文件，添加如下配置

spring:

 http:

  multipart:

   maxFileSize: 1MB

   maxRequestSize: 5MB

注：maxFileSize表示单个上传文件的大小，maxRequestSize表示多个文件一共的大小

异步上传文件

很多时候我们是异步上传图片的，选择后就上传然后进行浏览

1.新建fileUploadAjax.html

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>文件上传</title>

<script src="/plug/jquery/jquery-1.11.3.min.js"></script>

</head>

<body>

  <form action="" method="post" enctype="multipart/form-data" id="resource">

   上传文件：<input type="file" name="filename" id="filename"><br/>

      标&nbsp;&nbsp;题：<input type="text" name="title" id="title"><br/>

      备&nbsp;&nbsp;注：<input type="text" name="remark" id="remark"><br/>

  <input onclick="subResource()" type="button" value="提交"><br/>

  <img alt="没有上传图片" src="D:/upload/1.png" id="img1">

  </form>

</body>

<script type="text/javascript">

function subResource(){

       //$("form").serialize() 与new FormData 区别

       var formData = new FormData($("#resource")[0])

       $.ajax({

           url: "/helloFileUpdate",

           type: 'POST',

           data: formData,

           async: false,

           cache: false,

           contentType: false,

           processData: false,

           success: function (data) {

              $("#img1").attr("src",data.filePath);

           },

           error: function (data) {

              alert(data)

           }

       });

}

</script>

</html>

注：("form").serialize()和newFormData(("form").serialize()和 new FormData(("form").serialize()和newFormData((‘#uploadForm‘)[0])都是序列化表单，实现表单的异步提交，但是二者有区别：首先，前者，只能序列化表单中的数据，比如文本框等input select等的数据，但是对于文件，比如文件上传，无法实现，那么这时候，FormData就上场了

2.新建HelloController

@RestController

public class HelloController {

    @RequestMapping("/helloFileUpdate")

    public Object helloFileUpdate(MultipartFile filename,String remark,String title){

        System.out.println("文件名称"+filename.getOriginalFilename()+" remark="+remark+" title="+title);

        Map<String,Object> retMap = new HashMap<String,Object>();

        try {

            File file = new File("D:\\upload\\"+filename.getOriginalFilename());

            filename.transferTo(file);

            retMap.put("sign", "ok");

            retMap.put("filePath", file.getAbsolutePath());

            retMap.put("mes", "文件上传成功");

        } catch (IllegalStateException | IOException e) {

            e.printStackTrace();

            retMap.put("sign", "ok");

            retMap.put("mes", "文件上传失败");

        }

        return retMap;

    }

}

多文件上传

只要把接收参数 MultipartFile filename 修改为 MultipartFile[] filename 数组即可