OutputStreamWriter write（）

Question

我寫了一個小程序來跟蹤inputstream和outputstream的方法回調。

import java.io.FilterOutputStream; 
import java.io.IOException; 
import java.io.OutputStream; 
import java.io.OutputStreamWriter; 
import java.io.Writer; 

public class TracingOutputStream extends FilterOutputStream { 
private String key; 
private Writer log; 

public TracingOutputStream(OutputStream sink, String key, OutputStream log) { 
    super(sink); 
    this.key = key; 
    this.log = new OutputStreamWriter(log); 
} 

@Override 
public void write(byte[] b) throws IOException { 
    log.write(key + " write (byte [" + b.length + "])"); 
    log.write(114); 
    super.write(b); 
} 

@Override 
public void write(byte[] b, int off, int len) throws IOException { 
    log.write(key + " write (byte [" + b.length + "]" + " ," + off + len + ")"); 
    super.write(b, off, len); 
} 

@Override 
public void flush() throws IOException { 
    log.write(key + "flush()"); 
    super.flush(); 
} 

@Override 
public void close() throws IOException { 
    log.write(key + "close()"); 
    super.close(); 
} 

}

但是當我試圖主類TracingOutputStreamMain運行，什麼也沒有寫。有人可以給我解釋嗎

import java.io.*; 
import java.util.*; 

public class TracingOutputStreamMain { 
    public static void main(String... args) throws IOException { 
     try(ByteArrayOutputStream bytesOutput = new ByteArrayOutputStream(); 
     OutputStream fout = new FileOutputStream("log.txt"); 
     TracingOutputStream tracingOutput = new TracingOutputStream(bytesOutput, "ByteArray", fout); 
      BufferedOutputStream bufferedOutput = new BufferedOutputStream(tracingOutput); 
      TracingOutputStream tracingBufferedOutput = new TracingOutputStream(bufferedOutput, "Buffered", fout)) { 
      for(String arg: args) 
       tracingBufferedOutput.write(arg.getBytes()); 
     } 
     //System.out.println(Arrays.toString(bytesOutput.toByteArray())); 
    } 
} 

Answer 1

TracingOutputStream中使用的OutputStreamWriter從不關閉。關閉它，輸出將突然出現在輸出文件中。