Question

我有一个包含100万行文本的大型json文件。

我使用这种方法

String filePath = Thread.currentThread().getContextClassLoader()
            .getResource("text.json").getPath();
    fs=new FileInputStream(new File(filePath));
    BufferedReader br;
    br = new BufferedReader(new InputStreamReader(fs),10 * 1024 * 1024);
    String line = "";
    Map<String, Object> resultMap = null;
    StringBuilder sb=new StringBuilder();
    while ((line = br.readLine()) != null) {
        sb.append(line);
    }

但错误：堆空间蚀

我尝试修改VM参数-Xms

也不能使用

还有其他方法吗？

由于

Answer 1

尝试使用RandomAccessFile ::

正如@rossum建议的那样，在块中读取文件，执行操作并清除缓冲区数据。

public static String getInputString(String filepath)  throws IOException {
        RandomAccessFile randomAccessFile = new RandomAccessFile
                (filepath, "r");
        FileChannel channel = randomAccessFile.getChannel();
        ByteBuffer buffer = ByteBuffer.allocate(1024);      //Reading the file in chunk of 1024 bytes[1KB]
        StringBuilder sb = new StringBuilder("");
        while(channel.read(buffer) > 0)
        {
            buffer.flip();                                  //Ready for get ,put operation
            for (int i = 0; i < buffer.limit(); i++)
            {
                sb.append((char)buffer.get());              //Reading every character and appending to Stringbuilder            
            }
            buffer.clear();                                 //After performing opeartion clear the buffer
        }        
        channel.close();
        randomAccessFile.close();
        return sb.toString(); 
    }

Java读取大型JSON文件包含100万行文本

1 个答案: