代码如下:

package ErrorOperatorPack;import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;public class CopyFileDemo01 {public static void main(String[] args){}private static void method() {FileReader fr = null;FileWriter fw = null;try {fr = new FileReader("fr.txt");fw = new FileWriter("fw.txt");char[] chs = new char[1024];int len;while((len = fr.read())!=-1){fw.write(chs,0,len);}}catch (IOException e){e.printStackTrace();}finally {if (fr!=null)try {fr.close();}catch (IOException e){e.printStackTrace();}if (fw!=null){try{fw.close();}catch (IOException e){e.printStackTrace();}}}}}

代码如下:

package ErrorOperatorPack;import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;public class CopyFileDemo02 {public static void main(String[] args){}private static void method(){try(FileReader fr = new FileReader("fr.txt");FileWriter fw = new FileWriter("fw.txt");)   {char[] chs = new char[1024];int len;while((len = fr.read())!=-1){fw.write(chs,0,len);}}catch (IOException e){e.printStackTrace();}}}

代码如下:

package ErrorOperatorPack;import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;public class CopyFileDemo03 {public static void main(String[] args){}private static void method() throws IOException {FileReader fr = new FileReader("fr.txt");FileWriter fw = new FileWriter("fw.txt");try(fr;fw){char[] chs = new char[1024];int len;while((len = fr.read())!=-1){fw.write(chs,0,len);}}catch (IOException e){e.printStackTrace();}}
}