java 下传图片有关问题

public class FileUpLoad  extends ActionSupport{//"多文件上传就用list就可以了private List<File> file;"private File file;//上传文本的namepublic File getFile() {return file;}public void setFile(File file) {this.file = file;}private String fileContentType;//上传的文件类型。public String getFileContentType() {return fileContentType;}public void setFileContentType(String fileContentType) {this.fileContentType = fileContentType;}//获取上传文件的名称private String fileFileName;public String getFileFileName() {return fileFileName;}public void setFileFileName(String fileFileName) {this.fileFileName = fileFileName;}public String upload() throws Exception{//获取文件上传路径String root=ServletActionContext.getRequest().getRealPath("/upload");      InputStream is=new FileInputStream(file);      String.substring(fileFileName.indexOf("."));//截取上传文件的后缀。便于新定义名称。.jpg      System.out.println(name);File descFile=new File(root,新定义的文件名称+fileFileName.indexOf("."));OutputStream os=new FileOutputStream(descFile);byte[] buffer=new byte[1024];int length=0;while(-1!=(length=(is.read(buffer)))){os.write(buffer, 0, length);}is.close();os.close();return SUCCESS;}}