jsp上传文件

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jsp fileupload

1. jsp上传
Notice：
1. form表单 method 属性必须设置为 POST 方法，不能使用 GET 方法
2. form表单 enctype 属性需要设置为 multipart/form-data
3. form表单 action 属性需要设置为提交到后台处理文件上传的jsp文件地址或者servlet地址。例如 uploadFile.jsp 程序文件用来处理上传的文件
4. 上传文件元素需要使用 <input .../> 标签，属性设置为 type="file"。如果需要上传多个文件，可以在 <input .../>标签中设置不同的名称

Steps
首先我们先定义文件上传后存储在服务上的位置，你可以将路径写在你的程序当中，或者我们可以在web.xml配置文件中通过设置 context-param 元素来设置文件存储的目录

	<context-param>
		<param-name>file_upload_dir</param-name>
		<param-value>F:\files_uploaded</param-value>
		<description>Location to store uploaded files</description>
	</context-param>

依赖 FileUpload, 所以你需要在你的classpath中引入最新的 commons-fileupload.x.x.jar 包文件
FileUpload 依赖 Commons IO, 所以你需要在你的classpath中引入最新的 commons-io-x.x.jar

		<dependency>
			<groupId>commons-fileupload</groupId>
			<artifactId>commons-fileupload</artifactId>
			<version>1.2.2</version>
		</dependency>
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-io</artifactId>
			<version>1.3.2</version>
		</dependency>

在测试以下实例时，你需要上传确认上传的文件大小小于 maxFileSize 变量设置的大小 ,否则文件无法上传成功
确保你已经创建了目录F:\files_uploaded

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>Up load file</title>
</head>
<body>
	<form action="processFileUpload.jsp" method="post" enctype="multipart/form-data">
		<input type="file" size="50" name="fileSelected">
		<input type="submit" value="upload">
	</form>
</body>
</html>

processFileUpload.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%>
<%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory"%>    
<%@ page import="java.io.*,java.util.*,javax.servlet.*" %>   
<%@ page import="org.apache.commons.fileupload.*" %> 
<!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>
<%
	File file;
	int maxSize = 1024*1024*1024;
	int maxMemSize = 1024*1024;
	ServletContext ctx = pageContext.getServletContext();
	String filePath = ctx.getInitParameter("file_upload_dir");
	String contentType = request.getContentType();
	if(ServletFileUpload.isMultipartContent(request)) {
		DiskFileItemFactory factory = new DiskFileItemFactory();
		factory.setSizeThreshold(maxMemSize); //设置内存中存储文件的最大值
		factory.setRepository(new File("F:\\tmp"));
		ServletFileUpload servlet = new ServletFileUpload(factory);
		servlet.setSizeMax(maxSize); //设置最大的上传文件大小
		
		try {
			List items = servlet.parseRequest(request);
			out.println(items.size());
			Iterator it = items.iterator();
			while(it.hasNext()) {
				FileItem item = (FileItem) it.next();
				String fieldName = item.getFieldName();
				String fileName = item.getName();
				boolean isInMemory = item.isInMemory();
				long sizeInBytes = item.getSize();
				
				if(fileName.lastIndexOf("\\") >= 0) {
					file = new File(filePath, fileName.substring(fileName.lastIndexOf("\\")));
				} else {
					file = new File(filePath, fileName.substring(fileName.lastIndexOf("\\")+1));
				}
				
				item.write(file);
				out.println("Uploaded file: " + fileName);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
%>
</body>
</html>

NOTE：
代码copy自网络，起初，processFileUpload.jsp中的List items = servlet.parseRequest(request);得到的总是空集合，网上也有很多遇到这种情况的，原因在fileupload.jsp: name="fileSelected" ，如果没有name标记，commons fielupload不会作处理
servlet.setHeaderEncoding("UTF-8");中文名不会乱码

2. servlet上传

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
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 FileUploadServlet extends HttpServlet {

	private static final long serialVersionUID = 849325874174997377L;
	private static final int sizeThreshold = 1024*1024*1024;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		System.out.println(".....doGet.....");
		super.doGet(req, resp);
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		DiskFileItemFactory factory = new DiskFileItemFactory();
		ServletContext ctx = this.getServletContext();
		String filePath = ctx.getInitParameter("file_upload_dir");
		factory.setRepository(new File(filePath));
		factory.setSizeThreshold(sizeThreshold);
		ServletFileUpload upload = new ServletFileUpload(factory);
		
		try {
			@SuppressWarnings("unchecked")
			List<FileItem> list = upload.parseRequest(req);
			for(FileItem item : list) {
				String name = item.getFieldName();
				if(item.isFormField()) {
//					String value = item.getString();
//					req.setAttribute(name, value);
				} else {
					String value = item.getName();
					String fileName = value.substring(value.indexOf("\\")+1);
					req.setAttribute(name, fileName);
					OutputStream os = new FileOutputStream(new File(filePath, fileName));
					InputStream is = item.getInputStream();
					
					byte[] buff = new byte[1024];
					System.out.println("The length of " + value + " is " + item.getSize());
					
					int length = 0;
					while((length = is.read(buff)) != -1) {
						os.write(buff, 0, length);
					}
					is.close();
					os.close();
				}
			}
		} catch (FileUploadException e) {
			e.printStackTrace();
		}
		
		req.getRequestDispatcher("pages/upload_result.jsp").forward(req, resp);
	}

}

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class EncodingFilter implements Filter {

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		System.out.println("init EncodingFilter....");
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		request.setCharacterEncoding("utf-8");
		System.out.println("set the encoding to be utf-8 in EncodingFilter...");
		chain.doFilter(request, response);
	}

	@Override
	public void destroy() {
		System.out.println("destroy EncodingFilter....");
	}

}

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>Up load file</title>
</head>
<body>
	<form action="<%=request.getContextPath() %>/fileupload" method="post" enctype="multipart/form-data">
		<input type="file" size="50" name="fileSelected">
		<input type="submit" value="upload">
	</form>
</body>
</html>

upload_result.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>
<h3>File <%=request.getAttribute("fileSelected") %> uploaded successfully.</h3>
</body>
</html>

web.xml

<web-app>
	<display-name>Archetype Created Web Application</display-name>
	
	<context-param>
		<param-name>file_upload_dir</param-name>
		<param-value>F:\files_uploaded</param-value>
		<description>Location to store uploaded files</description>
	</context-param>	

	 <filter>
	 	<filter-name>EncodingFilter</filter-name>
	 	<filter-class>com.jesse.jsp.filter.EncodingFilter</filter-class>
	 </filter>
	 
	 <filter-mapping>
	 	<filter-name>EncodingFilter</filter-name>
	 	<url-pattern>/*</url-pattern>
	 </filter-mapping>
	 
	 <servlet>
	 	<servlet-name>fileUploadServlet</servlet-name>
	 	<servlet-class>com.jesse.jsp.servlet.FileUploadServlet</servlet-class>
	 </servlet>
	 
	 <servlet-mapping>
	 	<servlet-name>fileUploadServlet</servlet-name>
	 	<url-pattern>/fileupload</url-pattern>
	 </servlet-mapping>
</web-app>

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mysql常用命令 | jsp页面显示后台错误

2015-04-20 00:25
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