java文件上传资料 ctrl C + ctrl V again sorry everybody~

本文详细介绍 Apache FileUpload 组件的使用方法，包括文件上传到服务器的实现过程、上传文件到数据库的操作步骤以及常见问题解决方案。

apache fileupload：

common-fileupload是jakarta项目组开发的一个功能很强大的上传文件组件

下面先介绍上传文件到服务器（多文件上传）：

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.*;

import java.util.*;

import java.util.regex.*;

import org.apache.commons.fileupload.*;

public class upload extends HttpServlet {

private static final String CONTENT_TYPE = "text/html; charset=GB2312";

// Process the HTTP Post request

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType(CONTENT_TYPE);

PrintWriter out = response.getWriter();

try {

DiskFileUpload fu = new DiskFileUpload();

// 设置允许用户上传文件大小,单位:字节，这里设为2m

fu.setSizeMax(2 * 1024 * 1024);

// 设置最多只允许在内存中存储的数据,单位:字节

fu.setSizeThreshold(4096);

// 设置一旦文件大小超过getSizeThreshold()的值时数据存放在硬盘的目录

fu.setRepositoryPath("c:/windows/temp");

// 开始读取上传信息

List fileItems = fu.parseRequest(request);

// 依次处理每个上传的文件

Iterator iter = fileItems.iterator();

// 正则匹配，过滤路径取文件名

String regExp = ".+//(.+)$";

// 过滤掉的文件类型

String[] errorType = { ".exe", ".com", ".cgi", ".asp" };

Pattern p = Pattern.compile(regExp);

while (iter.hasNext()) {

FileItem item = (FileItem) iter.next();

// 忽略其他不是文件域的所有表单信息

if (!item.isFormField()) {

String name = item.getName();

long size = item.getSize();

if ((name == null || name.equals("")) && size == 0)

continue;

Matcher m = p.matcher(name);

boolean result = m.find();

if (result) {

for (int temp = 0; temp < errorType.length; temp++) {

if (m.group(1).endsWith(errorType[temp])) {

throw new IOException(name + ": wrong type");

}

try {

// 保存上传的文件到指定的目录

// 在下文中上传文件至数据库时，将对这里改写

item.write(new File("d:/" + m.group(1)));

out.print(name + "  " + size + " ");

} catch (Exception e) {

out.println(e);

}

} else {

throw new IOException("fail to upload");

}

} catch (IOException e) {

out.println(e);

} catch (FileUploadException e) {

out.println(e);

}

现在介绍上传文件到服务器，下面只写出相关代码：

以sql2000为例，表结构如下：

字段名：name filecode

类型： varchar image

数据库插入代码为：PreparedStatement pstmt=conn.prepareStatement("insert into test values(?,?)");

代码如下：

。。。。。。

try{
//item.write(new File("d://" + m.group(1)));//这段代码如果不去掉，将一同写入到服务器中

int byteread=0;

             InputStream inStream=item.getInputStream(); //读取输入流，也就是上传的文件内容
             pstmt.setString(1,m.group(1));
             pstmt.setBinaryStream(2,inStream,(int)size);
             pstmt.executeUpdate();
             inStream.close();

out.println(name+"  "+size+" ");
}

。。。。。。

这样就实现了上传文件至数据库

文件上传原理：

import java.io.*;

import java.util.*;

import javax.servlet.*;

import javax.servlet.http.*;

import javax.servlet.jsp.PageContext;

//确定您的环境中存在如上包

public class upload {

private ServletRequest request;

private ServletResponse response;

private ServletConfig config;

ServletInputStream DATA;

int FormSize;

File f1;

FileOutputStream os;

DataInputStream is;

String filename;

byte[] b;

byte t;

boolean flag = false;

public upload() {

}

// 初始化

public void initialize(ServletConfig config, HttpServletRequest request,

HttpServletResponse response) throws IOException {

this.request = request;

this.response = response;

this.config = config;

DATA = request.getInputStream();

FormSize = request.getContentLength();

}

public void initialize(PageContext pageContext) throws IOException {

request = pageContext.getRequest();

response = pageContext.getResponse();

config = pageContext.getServletConfig();

DATA = request.getInputStream();

FormSize = request.getContentLength();

}

public boolean setFilename(String s) {

try {

File f1 = new File(s);

os = new FileOutputStream(f1);

} catch (IOException e) {

return (false);

}

return (true);

}

public void getByte() {

int i = 0;

try {

is = new DataInputStream(DATA);

b = new byte[FormSize];

while (true) {

try {

t = is.readByte();

b[i] = t;

i++;

} catch (EOFException e) {

break;

}

is.close();

} catch (IOException e) {

}

public boolean save() {

int i = 0, start1 = 0, start2 = 0;

String temp = "";

if (!flag) {

getByte();

flag = true;

}

try {

temp = new String(b, "ISO8859_1");

} catch (UnsupportedEncodingException e) {

return (false);

}

start1 = temp.indexOf("image/");

temp = temp.substring(start1);

start1 = temp.indexOf(" ");

temp = temp.substring(start1 + 4);

start2 = temp.indexOf("; ");

if (start2 != -1) {

temp = temp.substring(0, start2);

}

try {

byte[] img = temp.getBytes("ISO8859_1");

for (i = 0; i < img.length; i++) {

os.write(img[i]);

}

os.close();

} catch (IOException e) {

return (false);

}

return (true);

}

新的：

在通过使用FileUpload组件上传的过程中，通过自己的调试，总结如下：
1）使用之前的准备，我用的是commons-fileupload-1.1-dev.jar和commons-io-1.1-dev.jar。
解释一下：尽管有的资料解释是commons-fileupload-1.0-beta.jar和commons-beanutils.jar，通过调试的结果
显示并不是需要commons-beanutils.jar文件，而是由于在parseRequest(request)的类有关继承于DiskFileItem
类。而他有private org.apache.commons.io.output.DeferredFileOutputStream dfos。这样的就必须使用到commons-io-1.1-dev.jar。因此需要导入该包。否则就出classNotFound：.DeferredFileOutputStream的错误。

2）由于涉及文件，就涉及到文件系统。然而在java或应用服务器中对于文件系统的访问，就有一定的安全策略。
需要将下列权限添加到您应用程序服务器的安全策略文件中：
permission java.io.FilePermission "<<ALL FILES>>", "read,write,delete";
具体是添加到../bea/weblogic81/server/lib/weblogic.policy中的.
否则会可能出如下异常错误：
org.apache.commons.fileupload.FileUploadException:
java.lang.reflect.InvocationTargetException
at
org.apache.commons.fileupload.FileUpload.createItem(FileUpload.java:615)
at
org.apache.commons.fileupload.FileUpload.parseRequest(FileUpload.java:474)
at
org.apache.commons.fileupload.FileUpload.parseRequest(FileUpload.java:355)
....

3）对于不同的服务器，在调试的过程中会出各种不一样的结果。这个与具体的服务器有关。

4）由于FileUpload在不断的更新版本，它的很多方法已经不推荐使用了（这与该组件的不断的改进有关）。通过对最新的帮助文档和网上的资料写了一个标准的程序如下：

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.*;

import java.util.*;

import java.util.regex.*;

import java.io.*;

import org.apache.commons.fileupload.servlet.*;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

* 创建日期 2005-4-10

* TODO 要更改此生成的文件的模板，请转至

* 窗口－首选项－ Java －代码样式－代码模板

/**

* @author gaolong1

* TODO 要更改此生成的类型注释的模板，请转至窗口－首选项－ Java －代码样式－代码模板

public class FileUpload2 extends HttpServlet {

/**

* Destruction of the servlet.

private String uploadPath = "D:/addnetFile/"; // 用于存放上传文件的目录

private File tempPath = new File("D:/addnetFile/tmp/"); // 用于存放临时文件的目录

public void destroy() {

super.destroy(); // Just puts "destroy" string in log

// Put your code here

}

/**

* The doPost method of the servlet.

* This method is called when a form has its tag value method equals to

* post.

* @param request

* the request send by the client to the server

* @param response

* the response send by the server to the client

* @throws ServletException

* if an error occurred

* @throws IOException

* if an error occurred

public void doPost(HttpServletRequest req, HttpServletResponse res)

throws ServletException, IOException {

res.setContentType("text/html; charset=GB2312");

PrintWriter out = res.getWriter();

System.out.println(req.getContentLength());

System.out.println(req.getContentType());

DiskFileItemFactory factory = new DiskFileItemFactory();

// maximum size that will be stored in memory

factory.setSizeThreshold(4096);

// the location for saving data that is larger than getSizeThreshold()

factory.setRepository(new File("d:/File/addnetFile/temp"));

ServletFileUpload upload = new ServletFileUpload(factory);

// maximum size before a FileUploadException will be thrown

upload.setSizeMax(1000000);

try {

List fileItems = upload.parseRequest(req);

// assume we know there are two files. The first file is a small

// text file, the second is unknown and is written to a file on

// the server

Iterator iter = fileItems.iterator();

// 正则匹配，过滤路径取文件名

String regExp = ".+//(.+)$";

// 过滤掉的文件类型

String[] errorType = { ".exe", ".com", ".cgi", ".asp" };

Pattern p = Pattern.compile(regExp);

while (iter.hasNext()) {

FileItem item = (FileItem) iter.next();

// 忽略其他不是文件域的所有表单信息

if (!item.isFormField()) {

String name = item.getName();

long size = item.getSize();

if ((name == null || name.equals("")) && size == 0)

continue;

Matcher m = p.matcher(name);

boolean result = m.find();

if (result) {

for (int temp = 0; temp < errorType.length; temp++) {

if (m.group(1).endsWith(errorType[temp])) {

throw new IOException(name + ": wrong type");

}

try {

// 保存上传的文件到指定的目录

// 在下文中上传文件至数据库时，将对这里改写

item.write(new File("d:/" + m.group(1)));

out.print(name + "  " + size + " ");

} catch (Exception e) {

out.println(e);

}

} else {

throw new IOException("fail to upload");

}

} catch (IOException e) {

out.println(e);

} catch (FileUploadException e) {

out.println(e);

}

// 保存上传的文件到指定的目录

// 在下文中上传文件至数据库时，将对这里改写

}

/**

* Initialization of the servlet.

* @throws ServletException

* if an error occure

public void init() throws ServletException {

// Put your code here

}