Question

我在这个空间遇到了麻烦。如何正确打印输出文件？当我运行我的代码时，就像......

这是我的main方法的样子，并生成输出文件......

main()....{
File stats = new File(statFile);
    stats.createNewFile();

// my code here.... the stat values change here.



    FileWriter statFileWriter = new FileWriter(stats, true);
    BufferedWriter statsOutput = new BufferedWriter(statFileWriter);
    statsOutput.write(Stats.printStat());
    statsOutput.flush();
}

这是我可以更改程序中的值的Stat类，并打印出带有值的字符串。

public class Stats {
public static String dataFile = "";
public static int cacheHits = 0;
public static int diskReads = 0;    
public static int diskWrites = 0;
public static long executionTime = 0;

public static String printStat() {
    String print = "";

    print += "Sort on " + dataFile;
    print += "\nCache Hits: " + cacheHits;
    print += "\nDisk Reads: " + diskReads;
    print += "\nDisk Writes: " + diskWrites;
    print += "\nTime is " + executionTime;
    return print;
}
}

这应该输出如下：

Sort on sorted_b.dat
Cache Hits: 30922
Disk Reads: 1
Disk Writes: 1
Time is 16
Sort on sorted_a.dat
Cache Hits: 62899
Disk Reads: 2
Disk Writes: 2
Time is 0

但是当我在测试用例中运行main两次时，实际输出是：

Sort on sorted_b.dat
Cache Hits: 30922
Disk Reads: 1
Disk Writes: 1
Time is 16Sort on sorted_a.dat    ------> the new stat is not start from the nextline.
Cache Hits: 62899
Disk Reads: 2
Disk Writes: 2
Time is 0

如果我添加额外＆＃34; / n＆＃34;在结束时 print + =＆＃34; \ nTime is＆＃34; + executionTime;这条线就像 print + =＆＃34; \ nTime is＆＃34; + executionTime + \ n;

最后会增加一行，比如

Sort on sorted_b.dat
Cache Hits: 30922
Disk Reads: 1
Disk Writes: 1
Time is 16
Sort on sorted_a.dat
Cache Hits: 62899
Disk Reads: 2
Disk Writes: 2
Time is 0
          ------------blank, but extra line.

如何在没有额外线的情况下打印输出，并正确打印？

Answer 1

将您的主要方法更改为：

File stats = new File(statFile);
Boolean fromStart = stats.createNewFile();

// my code here.... the stat values change here.  

FileWriter statFileWriter = new FileWriter(stats, true);
BufferedWriter statsOutput = new BufferedWriter(statFileWriter);
if(fromStart == false) statsOutput.write("\n");
statsOutput.write(Stats.printStat());
statsOutput.flush();

从Boolean fromStart返回的

stats.createNewFile()将是：

true如果文件是第一次创建的 - ＆gt;无需添加额外换行符。
false如果文件已存在 - ＆gt;在编写新内容之前需要添加换行符。

Answer 2

你需要在结尾追加“\ n”

public class Stats 
{
public static String dataFile = "";
public static int cacheHits = 0;
public static int diskReads = 0;    
public static int diskWrites = 0;
public static long executionTime = 0;

    public static String printStat() 
    {
        String print = "";

        print += "Sort on " + dataFile;
        print += "\nCache Hits: " + cacheHits;
        print += "\nDisk Reads: " + diskReads;
        print += "\nDisk Writes: " + diskWrites;
        print += "\nTime is " + executionTime+"\n";
        return print;
    }
}

Answer 3

在您的主要方法中，只需使用BufferedWriter的{{3}}方法，就像这样：

FileWriter statFileWriter = new FileWriter(stats, true);
BufferedWriter statsOutput = new BufferedWriter(statFileWriter);
statsOutput.write(Stats.printStat());
statsOutput.newLine();

如果愿意，您也可以在写入统计数据之前添加新行。

输出文件新行不从下一行开始

3 个答案: