1、java的包是不能导错的，导错基本就凉了，这点需要注意

2、new 出的流都要关闭，不然删不了。

package text;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.SequenceInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Properties;

public class GH {
	public static void main(String[] args) throws IOException, InterruptedException {
		File sFile = new File("E:\\test\\放到");
		if (!sFile.exists()) {
			sFile.mkdirs();
		}
		gefile("F:\\图片哦/38449e9e78bc30000006.jpg", "E:\\test\\放到");
		merge("E:\\test\\\\放到", "E:\\test\\新建文件夹");
		Thread.sleep(1000);
		ddelete("E:\\test\\放到");
		sFile.deleteOnExit();
	}

	/**
	 * path1是要割的文件路径，path2是文件割完要放入的路径
	 */
	public static void gefile(String path1, String path2) throws IOException {

		File file = new File(path1);
		FileOutputStream fileOutputStream = null;
		FileInputStream fileInputStream = new FileInputStream(file);
		byte[] d = new byte[1024 * 10];
		int len = 0;
		int count = 1;
		while ((len = fileInputStream.read(d)) != -1) {
			/**
			 * 重点：new 出来的FileOutoutStream都要关闭
			 */
			fileOutputStream = new FileOutputStream(new File(path2, count++ + ".part"));
			fileOutputStream.write(d);
			fileOutputStream.close();
		}
		fileOutputStream.flush();

		Properties properties = new Properties();
		properties.setProperty("num", count + "");// 因为要字符串所以count要+""
		properties.setProperty("filename", file.getName());
		fileOutputStream = new FileOutputStream(new File(path2, count + ".properties"));
		properties.store(fileOutputStream, "name");
		fileInputStream.close();
		fileOutputStream.close();
	}

	public static void merge(String path1, String path2) throws IOException, InterruptedException {
		/**
		 * path1是已割文件的路径 path2是合完文件要放入的路径
		 */
		File p1 = new File(path1);
		File[] part = p1.listFiles(new suffixfilter(".properties"));
		File pFile = part[0];
		Properties properties = new Properties();
		FileInputStream fileInputStream = new FileInputStream(pFile);
		properties.load(fileInputStream);// 把配置文件存到集合============
		int k = Integer.parseInt(properties.getProperty("num"));
		String string = properties.getProperty("filename");
//获取碎片文件
		File[] parts = p1.listFiles(new suffixfilter(".part"));
		ArrayList<FileInputStream> a1 = new ArrayList<FileInputStream>();
		for (int i = 0; i < k - 1; i++) {
			a1.add(new FileInputStream(parts[i]));
		}
		Enumeration<FileInputStream> enumeration = Collections.enumeration(a1);
		SequenceInputStream sis = new SequenceInputStream(enumeration);
		FileOutputStream fileOutputStream = new FileOutputStream((new File(path2, string)));
		int len = -1;
		byte[] s = new byte[1024 * 10];
		int o = 0;

		while ((len = sis.read(s)) != -1) {
			System.out.println(++o);
			fileOutputStream.write(s, 0, len);
		}

		fileOutputStream.flush();
		fileInputStream.close();
		fileOutputStream.close();
		sis.close();
		/**
		 * 删除合好的文件（图片）
		 */
		File d = new File(path2, string);
		Thread.sleep(2000);// 设置图片存在的时间
		d.delete();
	}

//删除新建的文件（放到）
	public static void ddelete(String path) throws IOException {
		File p1 = new File(path);
		File[] part = p1.listFiles(new suffixfilter(".properties"));
		File pFile = part[0];
		Properties properties = new Properties();
		FileInputStream fileInputStream = new FileInputStream(pFile);
		properties.load(fileInputStream);// 把配置文件存到集合============
		int k = Integer.parseInt(properties.getProperty("num"));
		String string = properties.getProperty("filename");
//获取碎片文件
		File[] parts = p1.listFiles(new suffixfilter(".part"));
		fileInputStream.close();
		/**
		 * 删除part文件
		 */
		for (int i = 0; i < k - 1; i++) {
			parts[i].delete();
		}
		/**
		 * 删除properties文件
		 */
		pFile.delete();
	}
}

基本上就是这样子。

补充：过滤器

package text;

import java.io.File;
import java.io.FilenameFilter;

public class suffixfilter implements FilenameFilter {
private String cString;
	public suffixfilter(String suffix) {
		// TODO Auto-generated constructor stub
		this.cString=suffix;
	}
	@Override
	public boolean accept(File dir, String name) {
		// TODO Auto-generated method stub
		return name.endsWith(cString);
	}

}