commonfileupload组件文件上传

/**
* @author Administrator
* 读取浏览器上传的内容（普通内容和上传内容）
* 并写入服务器指定的目录下存储
*/
public class UploadServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {

try {

/**
* DiskFileItemFactory
*    Method:setSizeThreshold 设置缓存空间
*    Method:setRepository 设置临时目录
*/

/**
* ServletFileUPload
*    method:setHeaderEncoding设置编码格式 UTF-8
*    parseRequest 解析request
*/

/**
* FileItem
*    method: isFormField 是否是表格字段
*    method: getFileName 获取表单名
*    method: getString()获取值,指定UTF-8
*    method: getName();
*    method: getSize();
*    method: getContent-type();
*
*
*/

//创建DiskFileItemFactory类
DiskFileItemFactory diskFileItemFactory = new DiskFileItemFactory();

//默认这个FileUpload上传组件，给上传文件开劈10K的缓存空间，设置为100K
diskFileItemFactory.setSizeThreshold(100*1024);

//设置这个FileUpload上传组件，上传文件时使用的临时目录，默认是java.io.tmpdir目录
String tempPath = this.getServletContext().getRealPath("/WEB-INF/temp");
diskFileItemFactory.setRepository(new File(tempPath));

//创建ServletFileUpload类
ServletFileUpload servletFileUpload = new ServletFileUpload(diskFileItemFactory);

//设置上传文件的编码方式
servletFileUpload.setHeaderEncoding("UTF-8");

/*
* 解析request中的上传内容，包含普通字段(上传人)和上传文件字段(选择文件)
* 返回的结果是浏览器上传的内容，每项内容以FileItem对象来表示，
* 其中上传人位于List[0]
* 其中上第一个上传文件位于List[1]
* 依次类推
*/
List<FileItem> fileItemList = servletFileUpload.parseRequest(request);

//迭代
for(FileItem fileItem : fileItemList){

//如果是普通字段的话，即上传人：哈哈
if(fileItem.isFormField()){

//获取普通字段的名字，例如：username
String fieldName = fileItem.getFieldName();

//获取普通字段的值，例如：哈哈
String fieldValue = fileItem.getString("UTF-8");

//显示
//System.out.println(fieldName+":"+fieldValue);

//如果是上传字段的话，即选择上传文件：e:/sh.jpg
}else{

//获取上传文件的大小，单位字节
long size = fileItem.getSize();

//如果超过了300K
if(size > 300 * 1024){

//抛出自定义异常
throw new FileSizeException();

}

//获取上传文件的类型
String contentType = fileItem.getContentType();

//如果类型是image/gif
/*if(!"image/gif".equals(contentType)){

//抛出自定义异常
throw new FileTypeException();
}*/

//获取上传文件的名字
String name = fileItem.getName();

//封装成File对象
File tempFile = new File(name);

//获取上传文件的真实文件名
String realFileName = tempFile.getName();

//封装服务器指定的上传目录
String uploadPath = this.getServletContext().getRealPath("/WEB-INF/upload");

//产生UUID真实文件名
String uuidRealFileName = this.makeUuidRealFileName(realFileName);

//产生子目录，例如：/WEB-INF/upload/12/6

Properties prop = new Properties();
String filePath = UploadServlet.class.getResource("/upload.properties").getFile();
prop.load(new FileInputStream(filePath));

//获取上一次路径
String lastPath = prop.getProperty("subUploadPath");

String subUploadPath;

if(lastPath!=null&&!"".equals(lastPath)){

File lastFile = new File(lastPath);

if(!lastFile.exists()){
lastFile.mkdir();
}
if(lastFile.list().length>=5){
subUploadPath = this.makeSubUpload(uploadPath,uuidRealFileName);
}else{
subUploadPath=lastPath;
}

}else{
subUploadPath = this.makeSubUpload(uploadPath,uuidRealFileName);
}

File file = new File(subUploadPath + "/" + uuidRealFileName);

//将上传文件以IO流的方式写入指定的目录下
fileItem.write(file);

//删除临时文件，在正常情况下，自动删除临时文件
fileItem.delete();

}
}
response.setContentType("text/html;charset=UTF-8");
PrintWriter pw = response.getWriter();
pw.write("<script>" +
"window.alert('上传文件成功');" +
"window.location.href='"+request.getContextPath()+"/upload.jsp';" +
"</script>");

}catch(FileTypeException e){
e.printStackTrace();
request.setAttribute("message","<font size='44'>上传文件类型必须是image/gif</font>");
request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request,response);
}catch(FileSizeException e){
e.printStackTrace();
request.setAttribute("message","<font size='44'>上传文件不得超过300K</font>");
request.getRequestDispatcher("/WEB-INF/message.jsp").forward(request,response);
}catch (Exception e) {
e.printStackTrace();
} finally{
//思考
}
}
//将UUID拼上真实文件名后返回
private String makeUuidRealFileName(String realFileName){
return UUID.randomUUID().toString()+"_"+realFileName;
}
//在upload总目录下，创建2层子目录，用于存上传的文件,分散总目录压力,子目录级数不限
private String makeSubUpload(String uploadPath,String uuidRealFileName) throws FileNotFoundException, IOException{

//获取hashCode整型值
int code = uuidRealFileName.hashCode();
//第一级子目录
int dir1 = code & 0xF;//12
//第二级子目录
int dir2 = ( code >> 1 ) & 0xF;//6
//创建这些子目录
File file = new File(uploadPath+"/"+dir1+"/"+dir2);
//如果不存在该子目录
if(!file.exists()){
//连续创建2个子目录
file.mkdirs();
}
System.out.println("程序创建目录后，保存......");
Properties prop = new Properties();
String filePath = UploadServlet.class.getResource("/upload.properties").getFile();
prop.load(new FileInputStream(filePath));
prop.setProperty("subUploadPath",file.getPath());
prop.store(new FileOutputStream(filePath), "Update subUploadPath'"+file.getPath()+"'");

//将创建后的子目录返回
return file.getPath();//可不可以返回一个路径

}
}