JavaWeb上传文件

JavaWeb上传文件

前端：

<p>导入文本分词：</p>
<form action="UploadServlet" enctype="multipart/form-data"method="post">
    <%--名称：<input name="txt_name" /><br>--%>
    上传文件：<input name="txt" type="file"><br>
    <input type="submit" value="提交"/> &nbsp;&nbsp;
    <input type="reset" value="重置"/>
</form>

设置Servlet：

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;
import org.apache.commons.fileupload.FileUploadException;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;




public class UploadServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        this.doPost(request, response);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        DiskFileItemFactory sf= new DiskFileItemFactory();//实例化磁盘被文件列表工厂
        String path = request.getRealPath("/upload");//得到上传文件的存放目录
        sf.setRepository(new File(path));//设置文件存放目录
        sf.setSizeThreshold(1024*1024);//设置文件上传小于1M放在内存中
        String rename = "";//文件新生成的文件名
        String fileName = "";//文件原名称
        String name = "";//普通field字段
        //从工厂得到servletupload文件上传类
        ServletFileUpload sfu = new ServletFileUpload(sf);

        try {
            List<FileItem> lst = sfu.parseRequest(request);//得到request中所有的元素
            for (FileItem fileItem : lst) {
                if(fileItem.isFormField()){
                    if("name".equals(fileItem.getFieldName())){
                        name = fileItem.getString("UTF-8");
                    }
                }else{
                    //获得文件名称
                    fileName = fileItem.getName();
                    fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
                    String houzhui = fileName.substring(fileName.lastIndexOf("."));
                    rename = UUID.randomUUID()+houzhui;
                    fileItem.write(new File(path, rename));
                }
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        response.sendRedirect("file.jsp");
        out.flush();
        out.close();
    }
}

注：注意导入commons-io-2.6.jar和commons-fileupload-1.4.jar，以区分tomcat中同名的api。

在web.xml中添加servlet:

    <servlet>
        <servlet-name>UploadServlet</servlet-name>
        <servlet-class>UploadServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>UploadServlet</servlet-name>
        <url-pattern>/UploadServlet</url-pattern>
    </servlet-mapping>

此时会出现中文文件名名乱码，在doPost()方法中添加如下即可：

		response.setContentType("text/html;charset=UTF-8");
        request.setCharacterEncoding("UTF-8");