文件复制异常java.nio.channels.ClosedChannelException

Question

// file copy 2
public static void ChannelCopy(File f1, File f2) throws Exception {
int length = 2097152;
FileInputStream in = new FileInputStream(f1);
FileOutputStream out = new FileOutputStream(f2);
FileChannel inC = in.getChannel();
FileChannel outC = out.getChannel();
ByteBuffer b = null;
while (true) {
if (inC.position() == inC.size()) {
inC.close();
outC.close();
}
if ((inC.size() - inC.position()) < length) {
length = (int) (inC.size() - inC.position());
} else
length = 2097152;
b = ByteBuffer.allocateDirect(length);
inC.read(b);
b.flip();
outC.write(b);
outC.force(false);
}
}
java.nio.channels.ClosedChannelException
at sun.nio.ch.FileChannelImpl.ensureOpen(Unknown Source)
at sun.nio.ch.FileChannelImpl.size(Unknown Source)
at com.cemso.util.FileOperationTool.ChannelCopy(FileOperationTool.java:138)
at com.cemso.util.InitServlet.createXmls(InitServlet.java:153)
at com.cemso.util.InitServlet.init(InitServlet.java:78)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1173)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:993)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4187)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4496)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:526)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:637)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:563)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:498)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1277)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:321)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:722)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:593)
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.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

Answer 1

顺序颠倒了，应该
 outC.close();
inC.close();
     

Answer 2

一样的。
异常抛在这行：
if ((inC.size() - inC.position()) < length) {

Answer 3

异常抛在这行：
if ((inC.size() - inC.position()) < length) {

Answer 4

// file copy 2
    public static void ChannelCopy(File f1, File f2) throws Exception {
        int length = 2097152;
        FileInputStream in = new FileInputStream(f1);
        FileOutputStream out = new FileOutputStream(f2);
        FileChannel inC = in.getChannel();
        FileChannel outC = out.getChannel();
        ByteBuffer b = null;
        while (true) {
            if (inC.position() == inC.size()) {
                inC.close();
                outC.close();
            }else{
            if ((inC.size() - inC.position()) < length) {
                length = (int) (inC.size() - inC.position());
            } else
                length = 2097152;
            b = ByteBuffer.allocateDirect(length);
            inC.read(b);
            b.flip();
            outC.write(b);
            outC.force(false);
          }
        }
    }

Answer 5

if (inC.position() == inC.size()) {
                inC.close();
                outC.close();
            }
FileChannel关闭以后，while循环还在执行所以就抛出异常了。
改为：if(inC.position() == inC.size()){
            inC.close();
            outC.close();
            break;
        }