如何在flink中读取hadoop序列文件？我用下面的方法遇到了多个问题。
我有：

DataSource<String> source = env.readFile(new SequenceFileInputFormat(config), filePath);

和

public static class SequenceFileInputFormat extends FileInputFormat<String> {
    ...
    @Override
    public void setFilePath(String filePath) {
        org.apache.hadoop.conf.Configuration config = HadoopUtils.getHadoopConfiguration(configuration);
        logger.info("Initializing:"+filePath);
        org.apache.hadoop.fs.Path hadoopPath = new org.apache.hadoop.fs.Path(filePath);

        try {
            reader = new SequenceFile.Reader(hadoopPath.getFileSystem(config), hadoopPath, config);
            key = (Writable) ReflectionUtils.newInstance(reader.getKeyClass(), config);
            value = (Writable) ReflectionUtils.newInstance(reader.getValueClass(), config);
        } catch (IOException e) {
            logger.error("sequence file creation failed.", e);
        }
    }

}
问题之一：无法读取用户代码 Package 器：sequencefileinputformat。