Java文件上传下载

Java文件上传下载

相关 jar 包：

commons-beanutils.jar

commons-collections.jar

commons-fileupload-1.2.2.jar

commons-io-2.4.jar

commons-lang.jar

commons-logging.jar

dom4j-1.6.1.jar

ezmorph-1.0.6.jar

jar 包下载：http://files.cnblogs.com/files/liaolongjun/common-jar.zip

　　　　void upload() throws Exception {
for (FileItem item : FileUtil.getFileItems(request)) {
ServletContext sc = request.getServletContext();
String path = sc.getRealPath("upload"); // 上传的文件存储路劲
String filename = item.getName();
File file = new File(path + File.separator + filename);
System.out.println(file);
if (file.exists() || file.createNewFile()) {
item.write(file); // 保存文件
}
// 输出 Base64 - item.get() 获取 byte[]
System.out.println("data:" + item.getContentType() + ";base64," + new String(Base64.encodeBase64(item.get())));
}
}

void download() throws Exception {
String filepath = request.getParameter("filepath");
File file = new File(filepath);
response.reset();
response.setContentType("application/x-msdownload");
response.addHeader("Content-Disposition", "attachment; filename=\"" + URLEncoder.encode(file.getName(), "utf-8") + "\"");
int fileLength = (int) file.length();
response.setContentLength(fileLength);
FileUtil.i2o(new BufferedInputStream(new FileInputStream(file)), response.getOutputStream());
}

FileUtil.getFileItems 方法：

/**
* DiskFileItemFactory 为解析器提供解析时的缺省的配置 <br>
* ServletFileUpload 解析 InputStream，将一个表单域(比如，一个文件输入框)中的数据封装到一个FileItem对象上<br>
* FileItem对象上提供了相应的方法来获取表单域中的数据
*/
public static List<FileItem> getFileItems(HttpServletRequest request) {
List<FileItem> fileItems = new ArrayList<>();
try {
ServletFileUpload sfu = new ServletFileUpload(new DiskFileItemFactory());
for (Object obj : sfu.parseRequest(request)) {
FileItem item = (FileItem) obj;
if (!item.isFormField()) { // 是否普通表单域
fileItems.add(item);
}
}
} catch (Exception e) {
throw new RuntimeException(e);
}
return fileItems;
}

　　

FileUtil.i2o 方法：

public static void i2o(InputStream is, OutputStream os) {
try {
byte[] b = new byte[1024 * 1024]; // 一次读取1M
int n = 0;
while ((n = is.read(b)) != -1)
os.write(b, 0, n);// 这个n还不能去了
is.close();
os.flush();
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}