Java Zip4J，外部文件流导致的空指针异常？

我正在尝试使用Zip4J将来自不同位置的一堆文件压缩到一个zip文件夹中。我有一个来自不同文件夹的文件的数组列表，当我在调用“zip.AddFile（file，params）”的列表中循环时，文件会被很好地添加，直到文件来自的文件夹。我得到了以下错误

 net.lingala.zip4j.exception.ZipException: java.lang.NullPointerException
        at net.lingala.zip4j.zip.ZipEngine.initAddFiles(ZipEngine.java:187)
        at net.lingala.zip4j.zip.ZipEngine.addFiles(ZipEngine.java:85)
        at net.lingala.zip4j.core.ZipFile.addFiles(ZipFile.java:292)
        at net.lingala.zip4j.core.ZipFile.addFile(ZipFile.java:250)
        at tasks.OutputTask.compressFiles(OutputTask.java:627)
        at tasks.OutputTask.uploadHelper(OutputTask.java:550)
        at tasks.OutputTask.uploadHelper(OutputTask.java:593)
        at tasks.OutputTask.uploadHelper(OutputTask.java:593)
        at tasks.OutputTask.uploadHelper(OutputTask.java:593)
        at tasks.OutputTask.uploadHelper(OutputTask.java:593)
        at tasks.OutputTask.upload(OutputTask.java:516)
        at tasks.OutputTask.call(OutputTask.java:279)
        at tasks.OutputTask.call(OutputTask.java:1)
        at javafx.concurrent.Task$TaskCallable.call(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
    Caused by: java.lang.NullPointerException
        at net.lingala.zip4j.zip.ZipEngine.prepareFileOutputStream(ZipEngine.java:433)
        at net.lingala.zip4j.zip.ZipEngine.removeFilesIfExists(ZipEngine.java:385)
        at net.lingala.zip4j.zip.ZipEngine.initAddFiles(ZipEngine.java:109)
        ... 17 more

代码本身是

        ZipFile zip;
        try {
            System.out.println("Creating zip: " + outputName);
            File zipfile;
            if ((zipfile = new File(outputName)).exists()) {
                zipfile.delete();
            }
            zip = new ZipFile(new File(outputName));

            ZipParameters params = new ZipParameters();
            if (encrypt) {
                params.setEncryptFiles(true);
                params.setEncryptionMethod(Zip4jConstants.ENC_METHOD_AES);
                params.setAesKeyStrength(Zip4jConstants.AES_STRENGTH_256);
                params.setPassword(Property.AES_ENCRYPTION_KEY.getValue());

            }
            params.setCompressionMethod(Zip4jConstants.COMP_DEFLATE);
            params.setCompressionLevel(Zip4jConstants.DEFLATE_LEVEL_NORMAL);
            for (File file : sourceFiles) {
                if (file.isFile()) {
                    try {
                        zip.addFile(file, params);
                    } catch (ZipException e) {
                        e.printStackTrace();
                    }
                }
          }

例如，下面是文件列表

files={C:/Folder1/img1，C/Folder1/txtFile，C:/Folder1/jar，C:/Folder2/img2}

代码将正常执行，直到它到达“C:/Folder2/img2”并返回上述错误。我试过了

params.setSourceExternalStream(true);

它提供了另一个错误，即外部源文件没有名称。任何帮助都将不胜感激。提前感谢

尝试添加 params.setFileNameInZip（文件名）； 参数setSourceExternalStream（true）