java合并多个txt文件

⑴ java中如何将两个文件合并到另一个文件

java可以使用FileChannel快速高效地将多个文件合并到一起，以下是详细代码：

importstaticjava.lang.System.out;
importjava.io.FileInputStream;
importjava.io.FileOutputStream;
importjava.io.IOException;
importjava.nio.ByteBuffer;
importjava.nio.channels.FileChannel;
importjava.util.Arrays;

publicclasstest{
publicstaticfinalintBUFSIZE=1024*8;
publicstaticvoidmergeFiles(StringoutFile,String[]files){
FileChanneloutChannel=null;
out.println("Merge"+Arrays.toString(files)+"into"+outFile);
try{
outChannel=newFileOutputStream(outFile).getChannel();
for(Stringf:files){
FileChannelfc=newFileInputStream(f).getChannel();
ByteBufferbb=ByteBuffer.allocate(BUFSIZE);
while(fc.read(bb)!=-1){
bb.flip();
outChannel.write(bb);
bb.clear();
}
fc.close();
}
out.println("Merged!!");
}catch(IOExceptionioe){
ioe.printStackTrace();
}finally{
try{if(outChannel!=null){outChannel.close();}}catch(IOExceptionignore){}
}
}
publicstaticvoidmain(String[]args){
mergeFiles("D:/output.txt",newString[]{"D:/in_1.txt","D:/in_2.txt","D:/in_3.txt"});
}
}

⑵ JAVA合并TXT文件数据

ok！我给你写完了，首先你在D盘下面见两个文件
分别是 file1.txt和file2.txt
如下所示
file1.txt
-----------------------------
id|name|class
1|test|class1
2|test2|class2
3|test3|class3

file2.txt
-----------------------------------
id|sex|teacher
1|male|wang
2|female|zhang
3|male|li

------------------------------------------
程序如下：
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class CombinFile {
private final String FILE1 = "d:\\file1.txt";
private final String FILE2 = "d:\\file2.txt";
private final String FILENAME="d:\\combinFile.txt";

private InputStream getFileStream(String fileName) throws FileNotFoundException{
FileInputStream fis = new FileInputStream(new File(fileName));
return fis;
}

private void combinFile() throws IOException{
FileOutputStream fos = new FileOutputStream(new File(FILENAME));
InputStream fis1 = getFileStream(FILE1);
InputStream fis2 = getFileStream(FILE2);
int len = 0;
while((len=fis1.read())!=-1){
fos.write(len);
}
System.out.println("第一个文件已经写到目标文件.....");
fis1.close();
fos.flush();

while((len=fis2.read())!=-1){
fos.write(len);
}

System.out.println("第二个文件已经写到目标文件");
fis2.close();
fos.flush();
fos.close();

System.out.println("文件整合完毕");
}

public static void main(String[] args) {
try {
new CombinFile().combinFile();
} catch (IOException e) {
e.printStackTrace();
}
}
}

--------------------------------------------------------
程序运行如下：
产生combinFile.txt文件，内容如下
id|name|class
1|test|class1
2|test2|class2
3|test3|class3
id|sex|teacher
1|male|wang
2|female|zhang
3|male|li

⑶ java合并两个txt文件并生成新txt

importjava.io.File;
importjava.io.FileNotFoundException;
importjava.io.PrintStream;
importjava.util.Arrays;
importjava.util.Collections;
importjava.util.LinkedList;
importjava.util.Scanner;

publicclassTest
{
	publicstaticfinalStringLINE=System.getProperty("line.separator");

	publicstaticint[]readfile(Scannerinput)
	{
		int[]a=newint[0];
		while(input.hasNextLine())
		{
			Stringline=input.nextLine().trim();
			int[]dest=newint[a.length+1];
			System.array(a,0,dest,0,a.length);
			dest[dest.length-1]=Integer.parseInt(line);
			a=dest;
		}
		input.close();
		returna;
	}

	publicstaticvoidwritefile(PrintStreamoutput,int[]a)
	{
		output.append(Arrays.toString(a).replaceAll("[\[\]\s]","").replaceAll(",",LINE));
		output.flush();
		output.close();
	}

	publicstaticint[]merge(int[]a,int[]b)
	{
		int[]dest=newint[a.length+b.length];
		System.array(a,0,dest,0,a.length);
		System.array(b,0,dest,a.length,b.length);
		returndest;
	}
}

classTest1
{
	publicstaticvoidmain(String[]args)
	{
		if(args.length!=3)
		{
			System.err.println("输入的参数个数不是3个");
			return;
		}
		try
		{
			Scannerinput=newScanner(newFile(args[0]));
			int[]a=Test.readfile(input);
			input=newScanner(newFile(args[1]));
			int[]b=Test.readfile(input);
			int[]dest=Test.merge(a,b);
			try
			{
				PrintStreamoutput=newPrintStream(args[2]);
				Test.writefile(output,dest);
			}
			catch(FileNotFoundExceptione)
			{
				e.printStackTrace();
			}
		}
		catch(FileNotFoundExceptione)
		{
			e.printStackTrace();
		}
	}
}

classTest2
{
	publicstaticvoidmain(String[]args)
	{
		if(args.length!=1)
		{
			System.err.println("输入的参数个数不是1个");
			return;
		}
		try
		{
			Scannerinput=newScanner(newFile(args[0]));
			int[]dest=Test.readfile(input);
			Arrays.sort(dest);
			PrintStreamoutput=newPrintStream(args[0]);
			Test.writefile(output,dest);
		}
		catch(FileNotFoundExceptione)
		{
			e.printStackTrace();
		}
	}
}

<Test3>
{
	inti;

	publicTest3(inti)
	{
		this.i=i;
	}

	@Override
	publicintcompareTo(Test3o)
	{
		if(o.i>i)
		{
			return-1;
		}
		elseif(o.i<i)
		{
			return1;
		}
		else
		{
			return0;
		}
	}

	@Override
	publicStringtoString()
	{
		returnString.format("%s",i);
	}

	publicstaticvoidmain(String[]args)
	{
		if(args.length!=3)
		{
			System.err.println("输入的参数个数不是3个");
			return;
		}
		LinkedList<Test3>list=newLinkedList<Test3>();
		try
		{
			Scannerinput1=newScanner(newFile(args[0]));
			Scannerinput2=newScanner(newFile(args[1]));
			while(true)
			{
				try
				{
					inta=Integer.parseInt(input1.nextLine().trim());
					intb=Integer.parseInt(input2.nextLine().trim());
					Test3ta=newTest3(a);
					Test3tb=newTest3(b);
					list.add(ta);
					list.add(tb);
				}
				catch(Exceptione)
				{
					break;
				}
			}
			input1.close();
			input2.close();
			Collections.sort(list);
			PrintStreamoutput=newPrintStream(args[2]);
			output.append(list.toString().replaceAll("[\[\]\s]","").replaceAll(",",Test.LINE));
			output.flush();
			output.close();
		}
		catch(FileNotFoundExceptione)
		{
			e.printStackTrace();
		}
	}
}

⑷ 如何使用java合并多个文件

使用java编程语言，对文件进行操作，合并多个文件，代码如下：

importstaticjava.lang.System.out;
importjava.io.FileInputStream;
importjava.io.FileOutputStream;
importjava.io.IOException;
importjava.nio.ByteBuffer;
importjava.nio.channels.FileChannel;
importjava.util.Arrays;

publicclasstest{

publicstaticfinalintBUFSIZE=1024*8;

publicstaticvoidmergeFiles(StringoutFile,String[]files){
FileChanneloutChannel=null;
out.println("Merge"+Arrays.toString(files)+"into"+outFile);
try{
outChannel=newFileOutputStream(outFile).getChannel();
for(Stringf:files){
FileChannelfc=newFileInputStream(f).getChannel();
ByteBufferbb=ByteBuffer.allocate(BUFSIZE);
while(fc.read(bb)!=-1){
bb.flip();
outChannel.write(bb);
bb.clear();
}
fc.close();
}
out.println("Merged!!");
}catch(IOExceptionioe){
ioe.printStackTrace();
}finally{
try{if(outChannel!=null){outChannel.close();}}catch(IOExceptionignore){}
}
}
//下面代码是将D盘的.txt2.txt3.txt文件合并成out.txt文件。
publicstaticvoidmain(String[]args){
mergeFiles("D:/output.txt",newString[]{"D:/1.txt","D:/2.txt","D:/3.txt"});
}
}

⑸ java如何合并多个大的txt文件（每个文件50M）。nio处理文件如何提高速度

这种情况java.io, nio没有大区别

byte[]buf=newbyte[8*1024];
try(OutputStreamout=newnewFileOutputStream(outfile)){
for(Filef:txtFiles){
try(FileInputStreamin=newFileInputStream(f)){
org.apache.commons.io.IOUtils.Large(in,out,buf);
}
}
}

要是linux下，shell里直接执行cat *.txt >out.txt就可以，回不用写答代码

⑹ Java如何高效合并多个文件

import static java.lang.System.out;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Arrays;

public class test {
public static final int BUFSIZE = 1024 * 8;
public static void mergeFiles(String outFile, String[] files) {
FileChannel outChannel = null;
out.println("Merge " + Arrays.toString(files) + " into " + outFile);
try {
outChannel = new FileOutputStream(outFile).getChannel();
for(String f : files){
FileChannel fc = new FileInputStream(f).getChannel();
ByteBuffer bb = ByteBuffer.allocate(BUFSIZE);
while(fc.read(bb) != -1){
bb.flip();
outChannel.write(bb);
bb.clear();
}
fc.close();
}
out.println("Merged!! ");
} catch (IOException ioe) {
ioe.printStackTrace();
} finally {
try {if (outChannel != null) {outChannel.close();}} catch (IOException ignore) {}
}
}
public static void main(String[] args) {
mergeFiles("D:/output.txt", new String[]{"D:/in_1.txt", "D:/in_2.txt", "D:/in_3.txt"});
}
}