java file对象获取文件大小

import java.io.File;

import java.text.DecimalFormat;

import java.io.FileInputStream;
public class GetFileSize

{

public longgetFileSizes(File f) throws Exception{//取得文件大小

long s=0;

if (f.exists()) {

FileInputStream fis = null;

fis = new FileInputStream(f);

s= fis.available();

} else {

f.createNewFile();

System.out.println("文件不存在");

}

return s;

}

// 递归

public longgetFileSize(File f)throws Exception//取得文件夹大小

{

long size = 0;

File flist[] = f.listFiles();

for (int i = 0; i < flist.length; i++)

{

if (flist[i].isDirectory())

{

size = size + getFileSize(flist[i]);

} else

{

size = size + flist[i].length();

}

}

return size;

}

publicString FormetFileSize(long fileS) {//转换文件大小

DecimalFormat df = new DecimalFormat("#.00");

String fileSizeString = "";

if (fileS < 1024) {

fileSizeString = df.format((double) fileS) + "B";

} else if (fileS < 1048576) {

fileSizeString = df.format((double) fileS / 1024) + "K";

} else if (fileS < 1073741824) {

fileSizeString = df.format((double) fileS / 1048576) + "M";

} else {

fileSizeString = df.format((double) fileS / 1073741824) +"G";

}

return fileSizeString;

}



public longgetlist(File f){//递归求取目录文件个数

long size = 0;

File flist[] = f.listFiles();

size=flist.length;

for (int i = 0; i < flist.length; i++) {

if (flist[i].isDirectory()) {

size = size + getlist(flist[i]);

size--;

}

}

return size;


}



publicstatic void main(String args[])

{

GetFileSize g = new GetFileSize();

long startTime = System.currentTimeMillis();

try

{

long l = 0;

String path = "C:\\WINDOWS";

File ff = new File(path);

if (ff.isDirectory()) { //如果路径是文件夹的时候

System.out.println("文件个数 " + g.getlist(ff));

System.out.println("目录");

l = g.getFileSize(ff);

System.out.println(path + "目录的大小为：" + g.FormetFileSize(l));

} else {

System.out.println(" 文件个数 1");

System.out.println("文件");

l = g.getFileSizes(ff);

System.out.println(path + "文件的大小为：" + g.FormetFileSize(l));

}



} catch (Exception e)

{

e.printStackTrace();

}

long endTime = System.currentTimeMillis();

System.out.println("总共花费时间为：" + (endTime - startTime) +"毫秒...");

}

}