I/O 流
输入流的几个常用方法：
1，复制一个文件;
import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class copyDeno { public static void copy(String src, String dest) {//src 原文件，dest 待复制的文件
//这儿需要加下判断src是否为文件和是否存在， InputStream in = null; OutputStream out = null; byte[] b = new byte[1024]; int len; try { in = new FileInputStream(src); out = new FileOutputStream(dest); while ((len=in.read(b) )!= -1) { out.write(b,0,len); } } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { if (in != null) { try { in.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (out != null) { try { out.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } } public static void copyWithBuffer(String src, String dest) {//以上加入缓冲流 InputStream in = null; OutputStream out = null; byte[] b = new byte[20]; int len; try { in = new BufferedInputStream(new FileInputStream(src)); out =new BufferedOutputStream(new FileOutputStream(dest)); while ((len=in.read(b) )!= -1) { out.write(b,0,len); } //out.flush(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { Release.free(in, out); } } public static void main(String[] args) throws IOException { copy("F:\\Word\\eclipseword\\a4\\file\\a.txt", "F:\\Word\\eclipseword\\a4\\copyfile\\a1.txt"); copyWithBuffer("F:\\Word\\eclipseword\\a4\\file\\b.txt", "F:\\Word\\eclipseword\\a4\\copyfile\\b1.txt"); } }
封装一个关闭流(释放资源)方法：
package IO;
import java.io.Closeable;
import java.io.IOException;
public class Release {
public static void free(Closeable...stream){
for(Closeable st:stream){
if(st != null){
try {
st.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
2,复制一个文件夹的所有内容到另外一个文件夹中
package IOfuxi;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import IO.Release;
/*复制多级文件夹
* A:封装数据源File
* B:封装目的地File
* C:判断该File是文件夹还是文件
* a:是文件夹
* 就在目的地目录下创建该文件夹
* 获取该File对象下的所有文件或者文件夹File对象
* 遍历得到每一个File对象
* 回到C
* b:是文件
* 就复制(字节流)
* */
public class CopyFolderduo {
public static void main(String[] args) throws IOException {
copyfolder("F:\\Word\\eclipseword\\a4\\file",
"D:\\Java视频\\day21\\day21");
}
private static void copyfolder(String src,String des) throws IOException{
File file=new File(src);
File newfile=new File(des);
//判断文件是否存在
if(!file.exists()||!newfile.exists()){
return;
}else{
fuzhi(file,newfile);
}
}
private static void fuzhi(File file, File newfile) throws IOException {
// 判断该File是文件夹还是文件
if(file.isDirectory()){
File newFloder=new File(newfile,file.getName());
//创建目标路径文件夹
newFloder.mkdir();
//// 获取该File对象下的所有文件或者文件夹File对象
File[] arrfile=file.listFiles();
for(File f:arrfile){
//递归调用
fuzhi(f,newFloder);
}
}else{
File newf=new File(newfile,file.getName());
copyfile(file,newf);
}
}
//复制文件的方法
private static void copyfile(File file, File newf) throws IOException {
BufferedInputStream in= new BufferedInputStream(new FileInputStream(file));
BufferedOutputStream out=new BufferedOutputStream(new FileOutputStream(newf));
byte[] arr=new byte[1024];
int len;
while((len=in.read(arr))!=-1){
out.write(arr, 0, len);
out.flush();
}
// out.flush();
Release.free(in,out);
}
}
3.压缩一个文件夹
1 package zy823; 2 3 import java.io.BufferedInputStream; 4 import java.io.BufferedOutputStream; 5 import java.io.File; 6 import java.io.FileInputStream; 7 import java.io.FileNotFoundException; 8 import java.io.FileOutputStream; 9 import java.io.InputStream; 10 import java.util.zip.ZipEntry; 11 import java.util.zip.ZipOutputStream; 12 13 public class zipFolder { 14 public static void zipFile(String src,String dest){ 15 ZipOutputStream zos = null; 16 try { 17 zos = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(dest)));// 18 File fileSrc = new File(src); 19 if(!fileSrc.exists()){ 20 throw new FileNotFoundException(); 21 }else{ 22 zip(fileSrc.getName(),zos,fileSrc); 23 zos.flush(); 24 zos.close(); 25 } 26 } catch (FileNotFoundException e1) { 27 // TODO Auto-generated catch block 28 e1.printStackTrace(); 29 }catch (Exception e) { 30 // TODO Auto-generated catch block 31 e.printStackTrace(); 32 } 33 34 } 35 private static void zip(String dest,ZipOutputStream zos,File src)throws Exception{ 36 byte[] b = new byte[1024]; 37 InputStream is = null; 38 if(src.isFile()){ 39 zos.putNextEntry(new ZipEntry(dest)); 40 is = new BufferedInputStream(new FileInputStream(src)); 41 int len; 42 while((len = is.read(b)) != -1){ 43 zos.write(b, 0, len); 44 } 45 zos.flush(); 46 is.close(); 47 zos.closeEntry(); 48 }else{ 49 File[] files = src.listFiles(); 50 zos.putNextEntry(new ZipEntry(dest+"/")); 51 for(File temp:files){ 52 zip(dest+"/"+temp.getName(),zos,temp); 53 } 54 } 55 } 56 57 }
