独立写出文件切割（合并），考验你的耐心，流和集..... - 黑马程序员技术交流社区

package com.itheima;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.SequenceInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Properties;
import java.util.Set;
/**
* 文件的切割与合并
* @author wfq
*/
public class Test9 {
public static void main(String[] args) {
// File file = new File("tempfile\\那片海.mp3");
File targfFile = new File("tempfile\\targfile");
// split(file,targfFile);
merger(targfFile);
}
//合并文件方法
public static void merger(File targfFile) {
//判断该文件是否存在且为目录
if(!(targfFile.exists()&&targfFile.isDirectory()))
throw new RuntimeException("该文件不存在或不是目录...");
//判断配置文件是否存在且唯一
File[] filesProp = targfFile.listFiles(new FilenameFilter() {
@Override
public boolean accept(File dir, String name) {
return name.endsWith(".properties");
}
});
if(!(filesProp.length==1))
throw new RuntimeException("配置文件不存在或不唯一...");
//创建属性集读取配置文件
Properties prop = new Properties();
BufferedInputStream propIn = null;
String fileName = null;
int fileCount = 0;
try {
propIn = new BufferedInputStream(new FileInputStream(filesProp[0]));
prop.load(propIn);
Set<String > propSet = prop.stringPropertyNames();
for (String string : propSet) {
fileName = string;
fileCount = Integer.parseInt(prop.getProperty(fileName));
}
} catch (IOException e) {
System.out.println("异常啦..");
} finally {
if(propIn!=null)
try {
propIn.close();
} catch (IOException e) {
e.printStackTrace();
}
}
//判断碎片文件是否缺失或不连续
File[] filesPart = targfFile.listFiles(new FilenameFilter() {
@Override
public boolean accept(File dir, String name) {
return name.endsWith(".part");
}
});
//判断碎片数异常
if(fileCount!=filesPart.length)
throw new RuntimeException("碎片数异常...");
//判断是否有碎片缺失
for (int i = 1; i <= fileCount; i++) {
File partFile = new File(targfFile, i+".part");
if(!partFile.exists())
throw new RuntimeException(partFile.getName()+"碎片缺失..");
}
//合并文件
mergerFile(targfFile,filesPart,fileName);
}
private static void mergerFile(File targfFile, File[] filesPart,
String fileName) {
//创建存储流的集合
ArrayList<FileInputStream> list = new ArrayList<FileInputStream>();
//存入关联每一个碎片文件的流对象
for (File file : filesPart) {
try {
list.add(new FileInputStream(file));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
//获取输入流的枚举
Enumeration<FileInputStream> en = Collections.enumeration(list);
//创建序列读取流
SequenceInputStream in = new SequenceInputStream(en);
//创建输出流
BufferedOutputStream out = null;
try {
out = new BufferedOutputStream(new FileOutputStream(new File(targfFile, fileName)));
byte[] buf = new byte[1024];
int len = 0;
while ((len=in.read(buf))!=-1) {
out.write(buf, 0, len);
out.flush();
}
} catch (IOException e) {
System.out.println("异常啦..");
} finally {
//关闭资源
if(in!=null)
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
if(out!=null)
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
//切割文件方法
public static void split(File file, File targfFile){
//判断被切割的文件是否是是文件并存在
if(!(file.isFile()&&file.exists()))
throw new RuntimeException("被切割的文件不存在或不是文件...");
//判断目标目录是否存在，不存在创建
if(!targfFile.exists())
targfFile.mkdir();
//创建属性集，持久化存储配置文件
Properties prop = new Properties();
//创建以该大小为单位的切割文件的缓冲数组
byte[] buf = new byte[1024*1024];
//创建读写流
BufferedInputStream bfi = null;
BufferedOutputStream bfo = null;
//记录生成文件编号
int fileNum = 0;
//完成切割
try {
bfi = new BufferedInputStream(new FileInputStream(file));
int len = 0;
while ((len=bfi.read(buf))!=-1) {
bfo = new BufferedOutputStream(new FileOutputStream(new File(targfFile, (++fileNum)+".part")));
bfo.write(buf, 0, len);
bfo.flush();
}
//记录配置数据
prop.setProperty(file.getName(), String.valueOf(fileNum));
bfo = new BufferedOutputStream(new FileOutputStream(new File(targfFile, (++fileNum)+".properties")));
//写出数据到配置文件
prop.store(bfo, "wfq");
} catch (IOException e) {
System.out.println("出错啦...");
} finally {
//关闭资源
if(bfi!=null)
try {
bfi.close();
} catch (IOException e) {
e.printStackTrace();
}
if(bfo!=null)
try {
bfo.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

复制代码