在 .ORC 文件中写入对象时遇到空指针异常

问题描述

我试图在 .ORC 文件中写入对象，但面临空指针异常

下面是我的代码

public static void main(String args[])
{
    
    List<Map<String,Object>> data = new LinkedList<>();
    Map< String,Object> map = new HashMap<String,Object>(){{
        put("order_id",1);
        put("item_name","Laptop");
        put("price",800.f);
    }};
    data.add(map);
    String path = "orders.orc";
    
    write(new Configuration(),path,"struct<order_id:int,item_name:string,price:float>",data);
    
}

 public static void write(Configuration configuration,String path,String struct,List<Map<String,Object>> data) throws IOException
{
    TypeDescription schema = TypeDescription.fromString(struct);
    VectorizedRowBatch batch = schema.createRowBatch();
    LongColumnVector orderIdColumnVector = (LongColumnVector) batch.cols[0];
    BytesColumnVector itemNameColumnVector = (BytesColumnVector) batch.cols[1];
    DoubleColumnVector priceColumnVector = (DoubleColumnVector) batch.cols[2];
    try(Writer writer = OrcFile.createWriter(new Path(path),OrcFile.writerOptions(configuration).setSchema(schema))){
//facing null pointer in writer
        System.out.println("Done 21");
        for (Map<String,Object> row : data) {
            int rowNum = batch.size++;          orderIdColumnVector.vector[rowNum] = (Integer) row.get("order_id");
            byte[] buffer = row.get("item_name").toString().getBytes(StandardCharsets.UTF_8);
            itemNameColumnVector.setRef(rowNum,buffer,buffer.length);
            priceColumnVector.vector[rowNum] = (Float) row.get("price");
            if (batch.size == batch.getMaxSize()) {
                writer.addRowBatch(batch);
                batch.reset();
            }
        }
        if (batch.size != 0) {
            writer.addRowBatch(batch);
        }
        System.out.println("ORC serialization ended.......");
    }
    catch(Exception e)
    {
        e.printstacktrace();
    }
}

面对错误

java.lang.NullPointerException
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1012)
    at org.apache.hadoop.util.Shell.runcommand(Shell.java:482)
    at org.apache.hadoop.util.Shell.run(Shell.java:455)
    at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:702)
    at org.apache.hadoop.util.Shell.execCommand(Shell.java:791)
    at org.apache.hadoop.util.Shell.execCommand(Shell.java:774)
    at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:646)
    at org.apache.hadoop.fs.FilterFileSystem.setPermission(FilterFileSystem.java:472)
    at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:460)
    at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:426)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:906)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:887)
    at org.apache.orc.impl.PhysicalFsWriter.<init>(PhysicalFsWriter.java:115)
    at org.apache.orc.impl.WriterImpl.<init>(WriterImpl.java:167)
    at org.apache.orc.OrcFile.createWriter(OrcFile.java:1004)

参考https://www.javahelps.com/2020/08/read-and-write-orc-files-in-core-java.html 我正在使用上述链接中使用的相同依赖项

请帮忙！

解决方法

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java java orc