标签：java上传文件 commons-fileupload multipart/form-data file
文件上传
导入commons-fileupload-1.2.2.jar
和commons-io-2.4.jar
1.设置jsp文件内的form表单
(1)method="post"方式提交;
(2)编码类型enctype="multipart/form-data";
(3)文件上传框<input type="file" name="file"/>必须设置name属性。
2.设置servlet页面
(1)设置request请求编码为"UTF-8";
(2)通过DiskFileItemFactory创建制造工厂
创建文件上传的核心类ServletFileUpload
(3)用ServletFileUpload.isMultipartContent(request)
判断request请求的编码类型是否是文件上传类型multipart/form-data
返回boolean值。
(4)获取上传文件的绝对路径。
(5)如果返回值是true，也就是说是文件上传编码类型，
则用得到的文件上传的核心类ServletFileUpload解析request
创建的文件上传类名.parseRequest(request)
(6)如果获取的集合不为空值，则进行遍历并且判断遍历的文件类型是否是普通输入框；
若是，则用InputStream流对文件进行读取，这是要注意浏览器获取文件名的兼容性，
为防止文件名获取错误，要对得到的文件名进行substring分割，
再用FileOutputStream流和buffer方法，将文件写入，关闭流，文件上传成功！
upload.jsp
<form action="${pageContext.request.contextPath}/uploadFileServlet" method="post" enctype="multipart/form-data">
用户名:<input name="uname"/>
文件上传：<input type="file" name="file"/>
<input type="submit" value="上传"/>
</form>uploadFileServlet.java
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
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 uploadFileServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
//获取DiskFileItemFactory
DiskFileItemFactory dfactory = new DiskFileItemFactory();
//2.获取文件上传的核心类ServletFileUpload
ServletFileUpload sfup = new ServletFileUpload(dfactory);
//3判断请求是否是multipart/form-data
boolean flag = ServletFileUpload.isMultipartContent(request);
//获取上传文件的绝对路径
String realPath = this.getServletContext().getRealPath("files");
System.out.println(this.getServletContext());
System.out.println(realPath);
if(flag){
try {
//解析request
List<FileItem> items = sfup.parseRequest(request);
if(items!=null){
//遍历
for (FileItem fileItem : items) {
//判断如果是普通输入框
if(fileItem.isFormField()){
String fieldName = fileItem.getFieldName();
String value = fileItem.getString();
System.out.println(fieldName+"---"+value);
}else{
//就是文件上传input
System.out.println("文件上传开始。。");
InputStream inputStream = fileItem.getInputStream();
//获取上传文件的文件名
String filename = fileItem.getName();
filename=filename.substring(filename.lastIndexOf("\\")+1);
System.out.println("文件名："+filename);
FileOutputStream fos = new FileOutputStream(realPath+"\\"+filename);
byte[] buffer = new byte[1024];
int len = 0;
while((len=inputStream.read(buffer))!=-1){
fos.write(buffer, 0, len);
}
inputStream.close();
fos.close();
System.out.println("文件上传成功！");
}
}
}
} catch (FileUploadException e) {
e.printStackTrace();
}
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
标签：java上传文件 commons-fileupload multipart/form-data file
原文地址：http://11836266.blog.51cto.com/11826266/1871233
