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Servlet-上传

Servlet-上传

作者: 通灵路耳 | 来源:发表于2020-06-20 17:57 被阅读0次
    1、前端页面upload.html 
    
    <!DOCTYPE html>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
     <!-- 1、method必须是post
          2、enctype表示提交的是二进制文件
          3、type="file"表示上传
      -->
    <form action="login" method="post" enctype="multipart/form-data">
      英雄名称:<input type="text" name="heroName" /> <br>
      上传头像 : <input type="file" name="filepath" /> <br>
      <input type="submit" value="上传">
    </form>
    
    2、导入jar包
    3、配置web.xml
      <servlet>
            <servlet-name>HelloServlet</servlet-name>
            <servlet-class>com.llhc.HelloServlet</servlet-class>
        </servlet>
        <servlet-mapping>
            <servlet-name>HelloServlet</servlet-name>
            <url-pattern>/login</url-pattern>
        </servlet-mapping>
    4、找到servlet接受上传文件
    
    package com.llhc;
    
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.InputStream;
    import java.io.PrintWriter;
    import java.util.Iterator;
    import java.util.List;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import org.apache.commons.fileupload.FileItem;
    import org.apache.commons.fileupload.FileUploadException;
    import org.apache.commons.fileupload.disk.DiskFileItemFactory;
    import org.apache.commons.fileupload.servlet.ServletFileUpload;
    
    public class HelloServlet extends HttpServlet {
          
        public void doPost(HttpServletRequest request, HttpServletResponse response) {
      
            String filename = null;
            try {
                //准备:上传文件对象
                DiskFileItemFactory factory = new DiskFileItemFactory();
                //准备:上传文件Servlet
                ServletFileUpload upload = new ServletFileUpload(factory);
                //准备:设置上传文件的大小限制为1M
                factory.setSizeThreshold(1024 * 1024);
                
                //获取:获取传输来的文件,放入List集合
                List items = null;
                try {
                    items = upload.parseRequest(request);
                } catch (FileUploadException e) {
                    e.printStackTrace();
                }
                
                //获取:遍历文件
                Iterator iter = items.iterator();
                while (iter.hasNext()) {
                    FileItem item = (FileItem) iter.next();
                    if (!item.isFormField()) {
      
                        //设置:文件名
                        filename = System.currentTimeMillis() + ".jpg";
                        //设置:通过uploaded自动获取到文件地址
                        String photoFolder =request.getServletContext().getRealPath("uploaded");
                        File f = new File(photoFolder, filename);
                        f.getParentFile().mkdirs();
      
                        //获取文件输入流
                        InputStream is = item.getInputStream();
      
                        //获取文件输出流
                        FileOutputStream fos = new FileOutputStream(f);
                        byte b[] = new byte[1024 * 1024];
                        int length = 0;
                        while (-1 != (length = is.read(b))) {
                            fos.write(b, 0, length);
                        }
                        fos.close();
      
                    } else {
                        System.out.println(item.getFieldName());
                        String value = item.getString();
                        value = new String(value.getBytes("ISO-8859-1"), "UTF-8");
                        System.out.println(value);
                    }
                }
                 
                String html = "<img width='200' height='150' src='uploaded/%s' />";
                response.setContentType("text/html");
                PrintWriter pw= response.getWriter();
                pw.format(html, filename);
                 
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    
    图片.png

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