【代码段】图片上传并显示

// 代码上传并显示：

项目目录：

jsp:只有一个文件。

fileUpload.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<form action = "upload" method = "post" encType="multipart/form-data">
		<input type="file" name="filepath">
		<input type="submit" value="提交">   
	</form>
</body>
</html>

 

src：只有一个文件。

UploadServlet.java:

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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;
/**
 * Servlet implementation class UploadServlet
 */
@WebServlet("/UploadServlet")
public class UploadServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doPost(HttpServletRequest request, HttpServletResponse response) 
			throws ServletException, IOException {
		// 1. 文件名
		String filename = null;
		// 2. 读取 request  list
		DiskFileItemFactory factory = new DiskFileItemFactory();
		ServletFileUpload upload = new ServletFileUpload(factory);
		factory.setSizeThreshold(1024*1024);
		List list = null;
		try {
			list = upload.parseRequest(request);
			System.out.println(list.toString());
		} catch (FileUploadException e) {
			e.printStackTrace();
		}
		// 3.  迭代到 FileItem
		Iterator iterator = list.iterator();
		while(iterator.hasNext()){
			FileItem fileItem = (FileItem) iterator.next();
			if(!fileItem.isFormField()){ // // 4. 判断   表单域返回 true  文件域返回 false
				// 5. 新建文件
				filename = System.currentTimeMillis() + ".jpg";
				String floder = request.getServletContext().getRealPath("floder");
				File file = new File(floder, filename);
				file.getParentFile().mkdirs();
				// 6. 流操作
				InputStream is = fileItem.getInputStream();
				FileOutputStream fos = new FileOutputStream(file);
				// 7. 写入
				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(fileItem.getFieldName());
				String value = fileItem.getString();
				value = new String(value.getBytes("ISO-8859-1"), "UTf-8");
				System.out.println(value);
			}
		}
		// 9. 显示
		String html = "<img width='200' height='200' src='floder/%s'>";
		response.setContentType("text/html");
		PrintWriter pw = response.getWriter();
		pw.format(html, filename);
	}

}

 

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
  <display-name>uploadTest_0821</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>upload.UploadServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>UploadServlet</servlet-name>
    <url-pattern>/upload</url-pattern>
  </servlet-mapping>

</web-app>

效果：

 

 

over