[英]Trying to write a loop that uses an OutputStream to write to a text file
我不是java程序員,我是VB程序員。 我這樣做是作為作業的一部分,但是,我並不是要求與作業相關的幫助。 我想弄清楚如何讓OutputStreamWriter
在這個實例中正常工作。 我只想捕獲我正在生成的值並將它們放入文本文檔中。 生成文件,但只存在一個條目,而不是我期望的40個條目。 我可以用VB實現這一點,但java現在感覺很奇怪。 非常感謝您的幫助。
謝謝,
史蒂夫
這是代碼:
public static void main(String[] args) {
long start, end;
double result,difference;
try {
//OutputStream code assistance from
// http://tutorials.jenkov.com/java-io/outputstreamwriter.html
OutputStream outputStream = new FileOutputStream("c:\\Temp\\output1.txt");
Writer out = new OutputStreamWriter(outputStream);
for(int n=1; n<=20; n++) {
//Calculate the Time for n^2.
start = System.nanoTime();
//Add code to call method to calculate n^2
result = mN2(n);
end = System.nanoTime();
difference = (end - start);
//Output results to a file
out.write("N^2 End time: " + end + " Difference: " +
difference + "\n");
out.close();
}
} catch (IOException e){
}
try {
OutputStream outputStream = new FileOutputStream("c:\\Temp\\output1.txt");
Writer out = new OutputStreamWriter(outputStream);
for(int n=1; n<=20; n++){
//Calculate the Time for 2^n.
start = System.nanoTime();
//Add code to call method to calculate 2^n
result = m2N(n);
end = System.nanoTime();
difference = (end - start);
//Output results to a file
out.write("N^2 End time: " + end + " Difference: " + difference + "\n");
out.close();
}
} catch (IOException e){
}
}
//Calculate N^2
public static double mN2(double n) {
n = n*n;
return n;
}
//Calculate 2N
public static double m2N(double n) {
n = 2*n;
return n;
}
你正在循環中關閉你的文件。 下一次循環時,您將嘗試寫入已關閉的文件,這將引發異常...但是在您捕獲IOException
您有一個空塊,這將有效地忽略該異常。
嘗試將out.close()
調用移動到finally
塊中,如下所示:
try {
...
}
catch ( IOExcetpion e) {
// Log any errors
}
finally {
out.close();
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.