Question

美好的一天。我试图让下面的代码写入一个txt文件。然而，我无法理解。它只是在输出部分的（“”）内打印代码。我的目标是创建文本文件以存储输出数据以便稍后检索。

public class Charlesshaw3Test {

public static void main(String[] args) throws Exception{

        **//checking id command line argument provided
        if(args.length==0) {
            System.out.println("C:\\Users\\bryon\\Desktop\\Java Programming");
            System.exit(1);
        }
        String fileName = args[0];

        BufferedWriter out = null;

        try {
            FileWriter fstream = new FileWriter(fileName);
            out = new BufferedWriter(fstream);
        } 

        catch (IOException ex) {
           System.out.println("\nCould not create file: "+ fileName+".");
            System.exit(1);
        }**


    //a) 10 Instances of the violin testing.
    CharlesShaw3Tst voilin[] = new CharlesShaw3Tst[10];
    for (int i = 0; i < 10; i++) {

        out.write("\n\n***Creating new violin object [" + (i + 1) + "]***");
        voilin[i] = new CharlesShaw3Tst();
        out.write("\nCreated");
        //b) tune your instruments,
        out.write("\nchecking if tuned?");
        out.write("\nVoilin tuned? " + voilin[i].isTuned());
        out.write("\nTuning...");
        voilin[i].setTuned(true);
        out.write("\nVoilin tuned? " + voilin[i].isTuned());
        //c) Start playing your instrument,
        out.write("\nVoilin playing? " + voilin[i].isPlaying());
        out.write("\nVoilin tuned? " + voilin[i].isTuned());
        out.write("\nCalling playVoilin method");
        voilin[i].playViolin();
        out.write("\nVoilin playing? " + voilin[i].isPlaying());
        // d) Call your unique method, and
        int num = voilin[i].getNumString();
        out.write("\nNumber of strings: " + num);
        out.write("\nString name: ");
        String strings[] = voilin[i].getviolinStrings();
        for (int s = 0; s < num; s++) {
            out.write(strings[s] + " ");
        }
        out.write("\n");
        //e) Stop playing your instruments.
        out.write("\nStopping playing..");
        voilin[i].stopViolin();
        out.write("\nVoilin playing? " + voilin[i].isPlaying());

        out.write("\nStopping tuning..");
        voilin[i].stopTuneViolin();
        out.write("\nVoilin tuned? " + voilin[i].isTuned());
    }
    //Close the output stream
    out.close();
}
}

Answer 1

尝试使用FileWriter的附加方法：

try {
    FileWriter writer = new FileWriter(file);

    writer.append("Your string");
    //Append all strings

    writer.flush();
    writer.close();            
} catch (IOException e) {
    e.printStackTrace();
}

Answer 2

它所指的前一个程序是：

公共课CharlesShaw3Tst {

private final int numString = 5; // number of strings
private final String violinStrings[] = {"E", "B", "G", "D", "A"}; //an array of strings
//fields to determine if the instrument is tuned,
 private boolean tuned;
//and if the instrument is currently playing.

私人布尔播放; //将调优和当前播放字段设置为false的构造方法。

public CharlesShaw3Tst() {
    this.tuned = false;
    this.playing = false;
}
// Other methods

public boolean isPlaying() {
    return playing;
}

public void setPlaying(boolean playing) {
    this.playing = playing;
}

public boolean isTuned() {
    return tuned;
}

public void setTuned(boolean isTuned) {
    this.tuned = isTuned;
}

public void playViolin() {
    System.out.println("The violin is now playing.");
    playing = true;
}

public void stopViolin() {
    System.out.println("The violin is now playing.");
    playing = true;
}

public void tuneViolin() {
    System.out.println("The violin is tuned.");
    tuned = true;
}

public void stopTuneViolin() {
    System.out.println("The violin is tuned.");
    tuned = false;
}



public int getNumString() {
   return this.numString ;
}

public String[] getviolinStrings() {
    return violinStrings;
}

}

无法从代码中获取Txt文件

2 个答案: