java java用新行写入文件末尾

java write to the end of file with new line

提问by LinCR

I want to write results to the end of the file using java

我想使用 java 将结果写入文件的末尾

FileWriter fStream;
        try {
            fStream = new FileWriter("recallPresision.txt", true);
            fStream.append("queryID=" + queryID + "         " + "recall=" + recall + "           Pres=" + presision);
            fStream.append("\n");
            fStream.flush();
            fStream.close();
        } catch (IOException ex) {
            Logger.getLogger(query.class.getName()).log(Level.SEVERE, null, ex);
        }

I put "\n"in the statement , it writes to the file but not with new line

我放入"\n"语句，它写入文件但不使用新行

I want to print results with new line

我想用新行打印结果

回答by Jeffrey

The newline sequence is system dependent. On some systems its \n, on others it's \n\r, \r\n, \ror something else entirely different. Luckily, Java has a built in property which allows you to access it:

换行序列取决于系统。在某些系统上它的\n，别人是\n\r，\r\n，\r或别的东西完全不同。幸运的是，Java 有一个内置属性，允许您访问它：

 String newline = System.getProperty("line.separator");

回答by Andrew Thompson

Wrong

错误的

fStream.append("\n");

Right

对

// don't guess the line separator!
fStream.append(System.getProperty("line.separator"));

回答by Paul Vargas

You could also change to:

您还可以更改为：

fStream = new FileWriter("recallPresision.txt", true);
PrintWriter out = new PrintWriter(fStream);
out.println("queryID=" + queryID + "         " + "recall=" + recall + "           Pres=" + presision);
out.flush();
out.close();
fStream.close();

回答by Kevin

It does print the newline, what you want is a blank line at the end. Add another \n.

它确实打印了换行符，你想要的是最后一个空行。添加另一个\n.

回答by Kevin

Try using \r\ninstead.

尝试使用\r\n。

Also, you should find that if you open your text file in a rich-text-editor, such as wordpad, your append has actually worked.

此外，您应该会发现，如果您在富文本编辑器（例如写字板）中打开文本文件，您的附加内容实际上已经起作用了。

Edit: Ignore me. Jeffery and Andrew's answers are much better.

编辑：无视我。杰弗里和安德鲁的答案要好得多。