初学者 Java文件读写

public static void readFileByLines(String fileName) {
File file = new File(fileName);
BufferedReader reader = null;
try {
System.out.println("以行为单位读取文件内容，一次读一行");
reader = new BufferedReader(new FileReader(file));
String tempString = null;
int line = 1;
//一次读一行，读入null时文件结束
while ((tempString = reader.readLine()) != null) {
//把当前行号显示出来
System.out.println("line " + line + ": " + tempString);
line++;
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e1) {
}
}
}
}

 int count = 0;
        try
        {
            BufferedReader input = new BufferedReader(
                    new InputStreamReader(new FileInputStream(
                            "C:\\Users\\base.txt"), "UTF-8"));
            BufferedWriter output = new BufferedWriter(new FileWriter(new File(
                    "result.sql")));
            while ((basedata = input.readLine()) != null)
            {
                count++;
                if(0==(count-1)%5000){
                    output = new BufferedWriter(new FileWriter(new File(
                            count+".sql")));
                }
                output.write(sql);
                output.newLine();                     
            }
            output.write("commit;");
            input.close();
            output.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class Test_16 {

	public static void main(String[] args) throws IOException {
		final String SrcFile = "D:\\tmp\\large_file.txt";
		final String TargetFolder = "D:\\tmp\\target";
		final int MaxShiftLines = 5000;
		File targetFolder = new File(TargetFolder);
		BufferedReader reader = new BufferedReader(new FileReader(SrcFile));
		BufferedWriter writer = null;
		try{
			String line = null;
			int fileIndex = 0;
			for(int lineCount=0;(line=reader.readLine())!=null;lineCount++){
				if(0==lineCount%MaxShiftLines){
					writer = shiftFileWriter(writer,targetFolder,fileIndex);
				}
				writer.write(line);writer.newLine();
			}
		}finally{
			reader.close();
			if(writer!=null)writer.close();
		}
	}

	private static BufferedWriter shiftFileWriter(BufferedWriter writer, File targetFolder, int fileIndex) throws IOException {
		if(writer!=null){
			writer.close();
		}
		String fileName = "target_"+fileIndex+".txt";
		File target = new File(targetFolder,fileName);
		return new BufferedWriter(new FileWriter(target));