io的学习4

news2024/11/13 8:13:49

打印流

分类：打印流一般是指：PrintStream、PrintWriter两个类

特点：

1.打印流只操作文件目的地，不操作数据源

2.特有的写出方法可以实现，数据原样写出

3.特有的写出方法，可以实现自动刷新，自动换行

解压缩流

解压本质：把每一个ZipEntry按照层级拷贝到本地另一个文件夹中。

package myzip;

import java.io.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class Zipdemo01 {
    public static void main(String[] args) {
        File src=new File("D:\\aaa.zip") ;
       File dest=new File("D:\\");
    }
    public static void unzip(File src,File dest) throws IOException {
        ZipInputStream zip=new ZipInputStream(new FileInputStream(src));
        ZipEntry entry ;
        while((entry=zip.getNextEntry())!=null){
            System.out.println(entry);
            if(entry.isDirectory()){
              File file=new File(dest,entry.toString()) ;
           file.mkdirs();
            }else {
                FileOutputStream fos=new FileOutputStream(new File(dest,entry.toString()));
int b;
while((b=zip.read())!=-1){
fos.write(b);
}
fos.close();
zip.closeEntry();
            }
        }
        zip.close();
    }
}

压缩流

/*一个文件夹压缩**/
package myzip;

import java.io.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class zipdemo03 {
    public static void main(String[] args) throws IOException {
        File src=new File("D:\\aaa");
        File destParent=src.getParentFile();
        File dest=new File(destParent,src.getName()+".zip");
        ZipOutputStream zos=new ZipOutputStream(new FileOutputStream(dest));
        toZip(src,zos,src.getName());
        zos.close();
    }
    public static void toZip(File src,ZipOutputStream zos,String name) throws IOException {
        File[] files = src.listFiles();
        for (File file : files) {
            if(file.isFile()){
                ZipEntry entry=new ZipEntry(name+"\\"+file.getName()) ;
                zos.putNextEntry(entry);
                FileInputStream fis=new FileInputStream(file);
                int b;
                while((b=fis.read())!=-1){
                   zos.write(b);
                }
                fis.close();
                zos.closeEntry();
            }else {
toZip(file,zos,name+"\\"+file.getName());
            }
        }
    }
}

package myzip;
/*一个文件压缩*/
import java.io.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class zipdemo02 {
    public static void main(String[] args) throws IOException {
        File src=new File("D:\\a.txt");
        File dest=new File("D:\\");
toZip(src,dest);
    }
    public static void toZip(File src,File dest) throws IOException {
        ZipOutputStream zos=new ZipOutputStream(new FileOutputStream(new File(dest,"a.zip")));
        ZipEntry entry=new ZipEntry("z.txt");
        zos.putNextEntry(entry);
        FileInputStream fis=new FileInputStream(src);
        int b;
        while((b=fis.read())!=-1){
            zos.write(b);
        }
        zos.closeEntry();
        zos.close();
    }
}