--------------------------------
java得到文件路径下的所有文件名
/*
*@param 声明File对象,指定参数filePath
*/
File dir = new File(filePath); //返回此抽象路径下的文件
File[] files = dir.listFiles();
if (files == null) return;
for (int i = 0; i < files.length; i++) { //判断此文件是否是一个文件
if (！files[i].isDirectory()){
System.out.println(files[i].getName());
}
}
--------------------------------
/**
* 上传文件
*
* @param file 上传文件实体
* @param filename 上传文件新命名
* @param dir 上传文件目录
* @return
*/
public static boolean uploadFile(File file, String dir, String filename) {
boolean ret = false;
try {
if (file != null) {
java.io.File filePath = new java.io.File(dir);
if (!filePath.exists()) {
filePath.mkdir();
}
String target = dir + filename;
FileOutputStream outputStream = new FileOutputStream(target);
FileInputStream fileIn = new FileInputStream(file);
byte[] buffer = new byte[1024];
int len;
while ((len = fileIn.read(buffer)) > 0) {
outputStream.write(buffer, 0, len);
}
fileIn.close();
outputStream.close();
ret = true;
}
} catch (Exception ex) {
log.info("上传文件无法处理，请确认上传文件！");
}
return ret;
}
/**
* 下载文件
*
* @param file 上传文件实体
* @param filename 上传文件新命名
* @param dir 上传文件目录
* @return
*/
public Actionforward downloadFile(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
try{
response.reset();
response.setContentType("application/vnd.ms-excel"); //改成输出excel文件
response.setHeader("Content-disposition","attachment; filename="+execlName );
//新建以文件outputfile 为目标的输出文件流
OutputStream out = response.getOutputStream();;
//将工作簿写入输出文件流，得到输出报表文件
pd.exportExcel(out) ;
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace () ;
}
return null;
}
--------------------------------
删除文件:
/**
* 删除文件
*
* @param filePathAndName 删除文件完整路径:d:/filedir/filename
* @return
*/
public static boolean delFile(String filePathAndName) {
boolean ret = false;
try {
new File(filePathAndName.toString()).delete();
ret = true;
} catch (Exception e) {
System.out.println("删除文件操作出错");
e.printStackTrace();
}
return ret;
}
----------------------------------------
删除目录下全部文件:
/**
* 删除目录下的文件
*
* @param dir 文件目录 d:/filedir/
* @return
*/
public static boolean delFiles(String dir) {
boolean ret = false;
try {
File filePath = new File(dir);// 查询路径
String[] files = filePath.list();// 存放所有查询结果
int i = 0;
for (i = 0; i < files.length; i++) {
new java.io.File(dir + "/" + files[i]).delete();
}
ret = true;
} catch (Exception e) {
e.printStackTrace();
}
return ret;
}
--------------------------------------------
判断文件是否存在
/**
* 判断文件是否存在
*
* @param filename
* @return
*/
public static boolean isExist(String filename) {
boolean ret = false;
try {
File file = new File(filename.toString());
if (file.exists()) {
ret = true;
}
} catch (Exception e) {
e.printStackTrace();
}
return ret;
}
-------------------------------------------------
根据制定路径，可以获取当前正在操作的文件的大小，容量为byte.
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class FileByte {
private String filePath = "D:\\m07012600030000001_z.wav";
private void getFileByte(){
File f = new File(filePath) ;
try{
FileInputStream fis = new FileInputStream(f) ;
try {
System.out.println(fis.available()) ;
}catch(IOException e1){
e1.printStackTrace();
}
}catch(FileNotFoundException e2){
e2.printStackTrace();
}
}
public static void main(String[] args)
{
FileByte fb = new FileByte();
fb.getFileByte();
}
}
-------------------------------------------------------
如何用java获取网络文件的大小(多线程)
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class saveToFile {
public void saveToFile(String destUrl, String fileName) throws IOException
{
FileOutputStream fos = null;
BufferedInputStream bis = null;
HttpURLConnection httpUrl = null;
URL url = null;
byte[] buf = new byte[2];
int size = 0;
int s=0;
//建立链接
url = new URL(destUrl);
httpUrl = (HttpURLConnection) url.openConnection();
//连接指定的资源
httpUrl.connect();
//获取网络输入流
bis = new BufferedInputStream(httpUrl.getInputStream());
//建立文件
fos = new FileOutputStream(fileName);
System.out.println("正在获取链接[" + destUrl + "]的内容...\n将其保存为文件[" + fileName + "]");
//保存文件
while ( (size = bis.read(buf)) != -1)
{
fos.write(buf, 0, size);
//++s;
System.out.println(size);
//System.out.println(s/1024+"M");
}
fos.close();
bis.close();
httpUrl.disconnect();
}
//多线程文件下载程序:
public class DownloadNetTest {
private File fileOut;
private java.net.URL url;
private long fileLength=0;
//初始化线程数
private int ThreadNum=5;
public DownloadNetTest(){
try{
System.out.println("正在链接URL");
url=new URL("http://211.64.201.201/uploadfile/nyz.mp3");
HttpURLConnection urlcon=(HttpURLConnection)url.openConnection();
//根据响应获取文件大小
fileLength=urlcon.getContentLength();
if(urlcon.getResponseCode()>=400){
System.out.println("服务器响应错误");
System.exit(-1);
}
if(fileLength<=0)
System.out.println("无法获知文件大小");
//打印信息
printMIME(urlcon);
System.out.println("文件大小为"+fileLength/1024+"K");
//获取文件名
String trueurl=urlcon.getURL().toString();
String filename=trueurl.substring(trueurl.lastIndexOf('/')+1);
fileOut=new File("D://",filename);
}
catch(MalformedURLException e){
System.err.println(e);
}
catch(IOException e){
System.err.println(e);
}
init();
}
private void init(){
DownloadNetThread [] down=new DownloadNetThread[ThreadNum];
try {
for(int i=0;i RandomAccessFile randOut=new RandomAccessFile(fileOut,"rw"); randOut.setLength(fileLength); long block=fileLength/ThreadNum+1; randOut.seek(block*i); down[i]=new DownloadNetThread(url,randOut,block,i+1); down[i].setPriority(7); down[i].start(); } //循环判断是否下载完毕 boolean flag=true; while (flag) { Thread.sleep(500); flag = false; for (int i = 0; i < ThreadNum; i++) if (!down[i].isFinished()) { flag = true; break; } }// end while System.out.println("文件下载完毕，保存在"+fileOut.getPath() ); } catch (FileNotFoundException e) { System.err.println(e); e.printStackTrace(); } catch(IOException e){ System.err.println(e); e.printStackTrace(); } catch (InterruptedException e) { System.err.println(e); } } private void printMIME(HttpURLConnection http){ for(int i=0;;i++){ String mine=http.getHeaderField(i); if(mine==null) return; System.out.println(http.getHeaderFieldKey(i)+":"+mine); } } //线程类 public class DownloadNetThread extends Thread{ private InputStream randIn; private RandomAccessFile randOut; private URL url; private long block; private int threadId=-1; private boolean done=false; public DownloadNetThread(URL url,RandomAccessFile out,long block,int threadId){ this.url=url; this.randOut=out; this.block=block; this.threadId=threadId; } public void run(){ try{ HttpURLConnection http=(HttpURLConnection)url.openConnection(); http.setRequestProperty("Range","bytes="+block*(threadId-1)+"-"); randIn=http.getInputStream(); } catch(IOException e){ System.err.println(e); } //////////////////////// byte [] buffer=new byte[1024]; int offset=0; long localSize=0; System.out.println("线程"+threadId+"开始下载"); try { while ((offset = randIn.read(buffer)) != -1&&localSize<=block) { randOut.write(buffer,0,offset); localSize+=offset; } randOut.close(); randIn.close(); done=true; System.out.println("线程"+threadId+"完成下载"); this.interrupt(); } catch(Exception e){ System.err.println(e); } } public boolean isFinished(){ return done; } } } } ---------------------------- pom.xml里面声明java的jar ---------------------------------------------- 获取的路径里有空格变成20%以后，用什么把这个还原 String path = "111120%"; path=path.replace（"20%"," "）; 13795111413 ---------------------------------------- 70 到 110 之间怎么随机呢？ int ss=(int)(71+Math.random()*(100-71+1)); System.out.println(ss); ------------------------------------------ 使用Calendar 处理时间格式 public static long parse(String dstr) { if (dstr == null || dstr.length() == 0) { return 0; } if (NumberUtils.isNumber(dstr)) { return Long.parseLong(dstr) * 86400000; } String year = ""; String month = ""; String day = ""; int flag = 1; char prech = 0; dstr=dstr.trim(); for (char ch : dstr.toCharArray()) { if (ch <= '9' && ch >= '0') { switch (flag) { case 1: year += ch; break; case 2: month += ch; break; case 3: day += ch; break; } } else { if (prech <= '9' && prech >='0') flag++; } prech = ch; } int y = year.equals("") ? 1970 : Integer.parseInt(year); int m = month.equals("") ? 1 : Integer.parseInt(month); int d = day.equals("") ? 1 : Integer.parseInt(day); Calendar cal = Calendar.getInstance(); cal.set(Calendar.YEAR, y); cal.set(Calendar.MONTH, m-1); cal.set(Calendar.DAY_OF_MONTH, d); return cal.getTimeInMillis(); } ------------------------------- 输出任何格式的时间 截取时间 public void InterceptionTime() { //先制造一个完整的时间. DateFormat allTimeFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS"); Date allTime = null; try { allTime = allTimeFormat.parse("2009-06-05 10:12:24.577"); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //截取时间,也可以使用下边的SimpleDateFormat DateFormat format = new SimpleDateFormat("HH:mm:ss.SSS"); String value = format.format(allTime); System.out.println(value); SimpleDateFormat dateFormat = new SimpleDateFormat ("yyyy-MM-dd"); String value2=dateFormat.format(allTime); System.out.println(value2); } --------------------------------- 转换2进制， lang包中Integer类中有个static String toBinaryString(int i) ---------------------------------------------- oracle怎么判断表是否存在 select count(*) into num from USER_TABLES where TABLE_NAME='T2' if num>0 then --存在 end if; ------------------------------------------------------ 记住帐号和密码 JS // 存cookie Cookie user = new Cookie("User_Name", "hsyd"); Cookie pass = new Cookie("Password", "hsyd"); response.addCookie(user); response.addCookie(pass); // 取cookie Cookie[] cookies = request.getCookies(); // ...找到匹配的cookie即可。 -----------------------------------------------------------------