java 实现将多个有序的日志文件 合并成一个有序的日志文件（RandomAccessFile实现 或者用 IO流实现【BufferedReader,BufferedOutputStream】）

基于IO流实现【BufferedReader,BufferedOutputStream】:

import java.io.*;

public class FileReaderObject {
	BufferedReader bufferedReader = null;

	public FileReaderObject(String filePath) {
		try {
			this.bufferedReader = new BufferedReader(new FileReader(new File(filePath)));
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}


	public String read () {
		String content;
		try {
			while ((content = bufferedReader.readLine()) != null) {
				return content;
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;

	}

	public void close() {
		try {
			bufferedReader.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

public class SortObject implements  Comparable<SortObject>{
	String content;
	FileReaderObject rd;

	public SortObject(FileReaderObject rd) {
		this.rd = rd;
		this.content = rd.read();
	}

	public  void next() {
		this.content = rd.read();
	}

	public String getContent() {
		return content;
	}

	public void setContent(String content) {
		this.content = content;
	}

	public FileReaderObject getRd() {
		return rd;
	}

	public void setRd(FileReaderObject rd) {
		this.rd = rd;
	}

	@Override
	public int compareTo(SortObject o) {
		if (o.content == null) {//当内容为空的时候，将null放在列表最后
			return  -1;
		}
		if (this.content == null) {//当内容为空的时候，将null放在列表最后
			return  1;
		}
		if (Integer.valueOf(this.content) > Integer.valueOf(o.content)) {
			return 1;
		}
		return  -1;
	}


}

import cn.rojao.util.FileUtil;

import java.io.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class SortUtill {

	public static void main(String[]args){
		FileReaderObject wrFile1 = new FileReaderObject("D:\\paixu\\a.txt");
		FileReaderObject wrFile2 = new FileReaderObject("D:\\paixu\\b.txt");
		FileReaderObject wrFile3 = new FileReaderObject("D:\\paixu\\c.txt");
		SortObject k1 = new SortObject(wrFile1);
		SortObject k2 = new SortObject(wrFile2);
		SortObject k3 = new SortObject(wrFile3);
		List<SortObject> sortObjectList = new ArrayList<>();
		sortObjectList.add(k1);
		sortObjectList.add(k2);
		sortObjectList.add(k3);
		Collections.sort(sortObjectList);
		FileUtil.createFile("D:\\paixu\\abc.txt");
		OutputStreamWriter write = null;
		BufferedOutputStream writer = null;
		try {
			writer = new BufferedOutputStream(new FileOutputStream(new File("D:\\paixu\\abc.txt")));
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		sort(writer,sortObjectList);
		wrFile1.close();
		wrFile2.close();
		wrFile3.close();
		try {
			writer.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}



	public static void sort(BufferedOutputStream bufferedOutputStream, List<SortObject> sortObjects) {
		while (true) {
			try {
				bufferedOutputStream.write(sortObjects.get(0).getContent().getBytes());
				bufferedOutputStream.write("\r\n".getBytes());
				bufferedOutputStream.flush();
			} catch (IOException e) {
				e.printStackTrace();
			}
			sortObjects.get(0).next();
			Collections.sort(sortObjects);
			if (sortObjects.get(0).getContent() == null || "".equals(sortObjects.get(0).getContent())) {
				break;
			}
		}
	}
}

基于RandomAccessFile实现：

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;

public class Ramdomaccfile {
	RandomAccessFile ramdom = null;

	public Ramdomaccfile(String filePath) {
		try {
			this.ramdom = new RandomAccessFile(filePath,"rw");
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}

	public void write(String content) {
		try {
			ramdom.seek(ramdom.length());
			ramdom.write(content.getBytes());
			ramdom.write("\r\n".getBytes());
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public String read () {
		String content;
		try {
			while ((content = ramdom.readLine()) != null) {
				String data = new String(content.getBytes("ISO-8859-1"), "utf-8");
				return data;
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;

	}

	public void close() {
		try {
			ramdom.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

public class SortObject implements  Comparable<SortObject>{
	String content;
	Ramdomaccfile rd;

	public SortObject(Ramdomaccfile rd) {
		this.rd = rd;
		this.content = rd.read();
	}

	public  void next() {
		this.content = rd.read();
	}

	public String getContent() {
		return content;
	}

	public void setContent(String content) {
		this.content = content;
	}

	public Ramdomaccfile getRd() {
		return rd;
	}

	public void setRd(Ramdomaccfile rd) {
		this.rd = rd;
	}

	@Override
	public int compareTo(SortObject o) {
		if (o.content == null) {
			return  -1;
		}
		if (this.content == null) {
			return  1;
		}
		if (Integer.valueOf(this.content) > Integer.valueOf(o.content)) {
			return 1;
		}
		return  -1;
	}


}

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class SortUtill {

	public static void main(String[]args){
		Ramdomaccfile wrFile1 = new Ramdomaccfile("D:\\paixu\\a.txt");
		Ramdomaccfile wrFile2 = new Ramdomaccfile("D:\\paixu\\b.txt");
		Ramdomaccfile wrFile3 = new Ramdomaccfile("D:\\paixu\\c.txt");
		SortObject k1 = new SortObject(wrFile1);
		SortObject k2 = new SortObject(wrFile2);
		SortObject k3 = new SortObject(wrFile3);
		List<SortObject> sortObjectList = new ArrayList<>();
		sortObjectList.add(k1);
		sortObjectList.add(k2);
		sortObjectList.add(k3);
		Collections.sort(sortObjectList);
		Ramdomaccfile openFile = new Ramdomaccfile("D:\\paixu\\abc.txt");
		sort(openFile,sortObjectList);
		wrFile1.close();
		wrFile2.close();
		wrFile3.close();
		openFile.close();
	}



	public static void sort(Ramdomaccfile ramdomaccfile, List<SortObject> sortObjects) {
		while (true) {
			ramdomaccfile.write(sortObjects.get(0).getContent());
			sortObjects.get(0).next();
			Collections.sort(sortObjects);
			if (sortObjects.get(0).getContent() == null || "".equals(sortObjects.get(0).getContent())) {
				break;
			}
		}
	}
}