-：=编辑简化=：-

在将代码从Linux（Ubuntu LTS 12.4）环境移植到Windows Server 2008的过程中，我遇到一个问题。

我需要使用内存映射文件，但无法在Windows上防止以下错误。

在下面的单元测试中重现了此问题。这两个测试在Linux上均成功完成，但是在Windows上，测试 testWithRandowmAccessFile
失败，并且堆栈跟踪位于底部。 testWithRandowmAccessFile 测试失败

的根本原因是什么？ 我应该如何在Windows上实现它？ ****

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import org.apache.commons.io.IOUtils;
import org.junit.Test;

public class TestIOOnWindows {

    @Test
    public void testWithRandowmAccessFile() throws IOException {
        final File sourceFile = new File("source.txt");
        final File manipulatedFile = new File("manipulated.txt");
        final File targetFile = new File("target.txt");

        try
        (
            FileInputStream sourceInputStream = new FileInputStream(sourceFile);
            RandomAccessFile manipulated = new RandomAccessFile(manipulatedFile, "rw");
            FileChannel fcOut = manipulated.getChannel()
        ) 
        {
            byte[] sourceBytes = new byte[Long.valueOf(sourceFile.length()).intValue()];
            IOUtils.read(sourceInputStream, sourceBytes);

            final int length = sourceBytes.length;

            // ========= with this single line on Windows, the move fails ======
            MappedByteBuffer byteBuffer = fcOut.map(FileChannel.MapMode.READ_WRITE, 0, length);
            // commenting this line would not prevent the error on Windows
            byteBuffer.put(sourceBytes, 0, length);            
        }

        Files.move(
                Paths.get(manipulatedFile.getAbsolutePath()),
                Paths.get(targetFile.getAbsolutePath()),
                StandardCopyOption.REPLACE_EXISTING);
    }

    @Test
    public void testWithFileOutputStream() throws IOException {
        final File sourceFile = new File("source.txt");
        final File manipulatedFile = new File("manipulated.txt");
        final File targetFile = new File("target.txt");

        try
        (
            FileInputStream sourceInputStream = new FileInputStream(sourceFile);
            FileOutputStream manipulatedOutputStream = new FileOutputStream(manipulatedFile);
            FileChannel fcIn = sourceInputStream.getChannel();
            FileChannel fcOut = manipulatedOutputStream.getChannel()
        ) 
        {
            final long length = sourceFile.length();

            // ========= with this single line on Windows, the move succeed ====
            fcIn.transferTo(0, length, fcOut);
        }

        Files.move(
                Paths.get(manipulatedFile.getAbsolutePath()),
                Paths.get(targetFile.getAbsolutePath()),
                StandardCopyOption.REPLACE_EXISTING);
    }
}

添加在Windows上从命令提示符运行单元测试时得到的跟踪跟踪。

There was 1 failure:
1) testWithRandowmAccessFile(TestIOOnWindows) java.nio.file.FileSystemException: C:\Users\Administrator\AppData\Local\Temp\manipulated.txt -> C:\Users\Administrator\AppData\Local\Temp\target.txt: The process cannot access the file because it is being used by another process.

    at sun.nio.fs.WindowsException.translateToIOException(Unknown Source)
    at sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source)
    at sun.nio.fs.WindowsFileCopy.move(Unknown Source)
    at sun.nio.fs.WindowsFileSystemProvider.move(Unknown Source)
    at java.nio.file.Files.move(Unknown Source)
    ===> at TestIOOnWindows.testWithRandowmAccessFile(TestIOOnWindows.java:40) <===
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:24)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:136)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:117)
    at org.junit.runner.JUnitCore.runMain(JUnitCore.java:98)
    at org.junit.runner.JUnitCore.runMainAndExit(JUnitCore.java:53)
    at org.junit.runner.JUnitCore.main(JUnitCore.java:45)

FAILURES!!!
Tests run: 2,  Failures: 1