MergeFile.java

package com.zhangzhihao.FileUpload.Java.Utils;

import org.jetbrains.annotations.NotNull;

import java.io.*;

import static com.zhangzhihao.FileUpload.Java.Utils.DeleteFolder.deleteFolder;
import static com.zhangzhihao.FileUpload.Java.Utils.StreamUtil.saveStreamToFile;


public class MergeFile {

    /**
     * @param chunksNumber
     * @param ext
     * @param guid
     * @param uploadFolderPath
     * @throws Exception
     */
    public static void mergeFile(final int chunksNumber,
                                 @NotNull final String ext,
                                 @NotNull final String guid,
                                 @NotNull final String uploadFolderPath)
            throws Exception {
        /*合并输入流*/
        String mergePath = uploadFolderPath + guid + "/";
        SequenceInputStream s ;
        InputStream s1 = new FileInputStream(mergePath + 0 + ext);
        InputStream s2 = new FileInputStream(mergePath + 1 + ext);
        s = new SequenceInputStream(s1, s2);
        for (int i = 2; i < chunksNumber; i++) {
            InputStream s3 = new FileInputStream(mergePath + i + ext);
            s = new SequenceInputStream(s, s3);
        }

        //通过输出流向文件写入数据
        saveStreamToFile(s, uploadFolderPath + guid + ext);

        //删除保存分块文件的文件夹
        deleteFolder(mergePath);

    }
}