解决BufferedReader.readLine()遇见的坑

package com.test;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
 
public class TestCh { 
	public void readDocFileToFtp() {
		String docPath = "H:\\11"; // 文件所在路径 模拟
		File file;
		try {
			file = new File(docPath);
			File[] files = file.listFiles();
			if (files.length == 0) {
				System.err.println(docPath + "文件夹下没有任何文件！");
			} else {
				Arrays.sort(files);
				System.err.println("文件数---" + files.length);
				for (int i = 0; i < files.length; i++) {
					if (files[i].isFile()) {
						InputStreamReader reader;
						reader = new InputStreamReader(new FileInputStream(files[i]));
						BufferedReader br = new BufferedReader(reader);
						String message = "";
						String line = "";
						long startTime = System.currentTimeMillis(); // 获取开始时间
						while ((line = br.readLine()) != null) {
							message += line;
						}
						br.close();
						long endTime = System.currentTimeMillis(); // 获取结束时间
						System.out.println("程序运行时间： " + (endTime - startTime) / 1000 + "ms");
 
						String fileName = files[i].getName();
 
						if (message.trim() == null || message.length() == 0) {
							System.err.println(fileName + "文件内容为空！");
						} else {
							// 上传文件
							System.err.println("上传===============");
						}
					}
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		} 
	}
	
	public static void main(String[] args) {
		TestCh te = new TestCh();
		te.readDocFileToFtp();
	} 
}

String readLine(boolean ignoreLF) throws IOException {
	StringBuffer s = null;
	int startChar;
        synchronized (lock) {
            ensureOpen();
	    boolean omitLF = ignoreLF || skipLF;
	    bufferLoop:
	    for (;;) {
		if (nextChar >= nChars)
		    fill(); //在此读数据
		if (nextChar >= nChars) { 
		    if (s != null && s.length() > 0)
			return s.toString();
		    else
			return null;
		}
      ......//其它
}
 
private void fill() throws IOException {
	..../其它
	int n;
	do {
	    n = in.read(cb, dst, cb.length - dst); //实质
	} while (n == 0);
	if (n > 0) {
	    nChars = dst + n;
	    nextChar = dst;
	}
    }

br = new BufferedReader(reader,510241024);//设置缓存大小:5M