Java try()语句实现try-with-resources异常管理机制操作

public interface AutoCloseable{
    public void close() throws Exception;
}

package stream; 
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException; 
public class TestStream { 
    public static void main(String[] args) {
        File f = new File("d:/test.txt");
        FileInputStream fis = null;
        try {
            fis = new FileInputStream(f); 
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 在finally 里关闭流
            if (null != fis)
                try { 
                    fis.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        } 
    }
}

package stream;  
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;  
public class TestStream {  
    public static void main(String[] args) {
        File f = new File("d:/lol.txt");
  
        //把流定义在try()里,try,catch或者finally结束的时候，会自动关闭
        try (FileInputStream fis = new FileInputStream(f)) {
            byte[] all = new byte[(int) f.length()];
            fis.read(all);
            for (byte b : all) {
                System.out.println(b);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }  
    }
}

package test; 
public class TestAutoCloseable implements AutoCloseable{
 public TestAutoCloseable() {
  System.out.println("class TestAutoCloceable");
 }
 public void close() {
  System.out.println("function close() executed");
 }
}

package test; 
public class TestFeature { 
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  try(TestAutoCloseable testAutoCloseable = new TestAutoCloseable()){   
  }
 } 
}

public class CloseTest {
    public static void main(String[] args){ 
        FileInputStream fileInputStream = null;
        try {
            fileInputStream = new FileInputStream("file.txt");
            fileInputStream.read();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if (fileInputStream != null){
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

public class CloseTest {
    public static void main(String[] args) {
        try (FileInputStream fileInputStream1 = new FileInputStream("file1.txt");
             FileInputStream fileInputStream2 = new FileInputStream("file2.txt")) {
            fileInputStream1.read();
            fileInputStream2.read();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public static void main(String[] args) {
  try {
    FileInputStream inputStream = new FileInputStream(new File("test"));
    Throwable var2 = null;
 
    try {
      System.out.println(inputStream.read());
    } catch (Throwable var12) {
      var2 = var12;
      throw var12;
    } finally {
      if (inputStream != null) {
        if (var2 != null) {
          try {
            inputStream.close();
          } catch (Throwable var11) {
            var2.addSuppressed(var11);
          }
        } else {
          inputStream.close();
        }
      } 
    } 
  } catch (IOException var14) {
    throw new RuntimeException(var14.getMessage(), var14);
  }
}

var2.addSuppressed(var11);

 /**
     * Returns an array containing all of the exceptions that were
     * suppressed, typically by the {@code try}-with-resources
     * statement, in order to deliver this exception.
     *
     * If no exceptions were suppressed or {@linkplain
     * #Throwable(String, Throwable, boolean, boolean) suppression is
     * disabled}, an empty array is returned.  This method is
     * thread-safe.  Writes to the returned array do not affect future
     * calls to this method.
     *
     * @return an array containing all of the exceptions that were
     *         suppressed to deliver this exception.
     * @since 1.7
     */
    public final synchronized Throwable[] getSuppressed() {
        if (suppressedExceptions == SUPPRESSED_SENTINEL ||
            suppressedExceptions == null)
            return EMPTY_THROWABLE_ARRAY;
        else
            return suppressedExceptions.toArray(EMPTY_THROWABLE_ARRAY);
    }