我试图运行一个模拟器，有几个问题，主要是....
- 代码不打印程序末尾的值
- 代码实际上并不创建文件
- 我很累，所以原谅我犯的任何愚蠢的错误或我遗漏的细节。
我搜索了网站，发现了这个
What is the simplest way to write a text file in java
和
how to write to text file outside of netbeans
我以为我可以编辑第一个链接中的代码为我工作，但这不起作用（这就是你在这里看到的）
第二页看起来更简单，但没有周围的代码所以我不确定上下文是什么以及我将如何实现它
import java.util.Random;
import java.util.Scanner;
import java.io.*;
/*
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
*/
public class SimClass {
public static void main (String[] args)
{
Scanner keyboard = new Scanner(System.in) ;
Random randomNumbers = new Random();
//create object from random class
//create self explanaroty input parameters
int pkt_in_q = 0 ;
int pkt_dropped = 0;
int input ;
int output ;
int buffer ;
int x ;
double y ;
//ask for values for buffer size. input rate, output rate
y = randomNumbers.nextDouble();
//attempt to assign a random number to the variable and
/*here you should get user input.
buffer size, # of repitions , if
*/
//fix this
System.out.print("Enter an integer for the input rate ");
input = keyboard.nextInt();
System.out.print("Enter an integer for the output rate ");
output = keyboard.nextInt();
System.out.print("What is the buffer size ");
buffer = keyboard.nextInt();
for (x = 1000000; x >=0 ; x--)
{ /*
simulate # of packets dropped/in the que,
create file, write results to file, output results,
*/
if (y > input/(output/buffer))
{
if (pkt_in_q < buffer)
{
pkt_in_q++ ;
}
else
{
pkt_dropped++ ;
}
//if statement should terminate here
}
else
if (pkt_in_q > 0)
{
pkt_in_q -- ;
}
}
/*
create file, write results to file, output results,
*/
try { /*this seeems to be the problem, the program is either not doing
anything with this or not making the results visible
*/
String content =( " pkt_in_q is " + pkt_in_q +
"pkt_dropped is " + pkt_dropped);
File file = new File("C:/Temp/inputFile.txt");
// if file doesnt exists, then create it
if (!file.exists())
{
file.createNewFile();
}
FileWriter fw = new FileWriter(file.getAbsoluteFile());
try (BufferedWriter bw = new BufferedWriter(fw))
{
bw.write(content);
bw.close();
}
System.out.println("packets dropped value is = " +
pkt_dropped + "packets in q value is = " + pkt_in_q);
}
catch (IOException e)
{
//e.printStackTrace();
}
}
}
答案 0 :(得分：0)
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
Random randomNumbers = new Random();
//create object from random class
//create self explanaroty input parameters
int pkt_in_q = 0;
int pkt_dropped = 0;
int input;
int output;
int buffer;
int x;
double y;
//ask for values for buffer size. input rate, output rate
y = randomNumbers.nextDouble() * 10;
System.out.println("Y++++++" + y);
//attempt to assign a random number to the variable and
/*here you should get user input.
buffer size, # of repitions , if
*/
//fix this
System.out.print("Enter an integer for the input rate ");
input = keyboard.nextInt();
System.out.print("Enter an integer for the output rate ");
output = keyboard.nextInt();
System.out.print("What is the buffer size ");
buffer = keyboard.nextInt();
for (x = 1000000; x >= 0; x--) { /*
simulate # of packets dropped/in the que,
create file, write results to file, output results,
*/
if (y > input / (output / buffer)) {
if (pkt_in_q < buffer) {
pkt_in_q++;
} else {
pkt_dropped++;
}
//if statement should terminate here
} else if (pkt_in_q > 0) {
pkt_in_q--;
}
}
/*
create file, write results to file, output results,
*/
try { /*this seeems to be the problem, the program is either not doing
anything with this or not making the results visible
*/
String content = (" pkt_in_q is " + pkt_in_q + "pkt_dropped is " + pkt_dropped);
String folderPath = "D:" + File.separator + "Temp";
String fileName = folderPath + File.separator + "inputFile.txt";
File folder = new File(folderPath);
File file = new File(fileName);
folder.mkdir();
// if file doesnt exists, then create it
if (!file.exists()) {
//file.mkdir();
file.createNewFile();
System.out.println("File created");
}
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
try {
bw.write(content);
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("packets dropped value is = " + pkt_dropped
+ "packets in q value is = " + pkt_in_q);
} catch (IOException e) {
//e.printStackTrace();
}
}
更正了代码检查，并根据您的要求更改文件目录和文件夹目录。
更正细节：
首先，您无法定义如下所示的试用块
try (BufferedWriter bw = new BufferedWriter(fw))
应该定义为
try{
}
catch(IOException e)
{
//do something
}
修改后的代码如下所示：
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
try
{
bw.write(content);
bw.close();
}
catch (IOException e)
{
//e.printStackTrace();
}
其次，您必须先创建目录，然后才能在目录中创建文件。所以只需修改代码即可创建目录并创建文件。
String folderPath = "D:" + File.separator + "Temp";
String fileName = folderPath + File.separator + "inputFile.txt";
File folder = new File(folderPath);
File file = new File(fileName);
folder.mkdir();
希望它澄清你的怀疑。
答案 1 :(得分：0)
我认为代码由于文件路径错误而无法执行。
val splitString: (String => Seq[String]) = { s =>
val seq = s.split(",").map(i => i.trim).toSeq
// Remove "u[" from the first element and "]" from the last:
Seq(seq(0).drop(2)) ++
seq.drop(1).take(seq.length-2) ++
Seq(seq.last.take(seq.last.length-1))
}
import org.apache.spark.sql.functions._
val newDF = df_records
.withColumn("authors_array", udf(splitString).apply(col("_authors")))
C中没有名为“Temp”的文件夹 开车。如果你手动创建Temp文件夹，那么代码将成功执行。
File file = new File("C:/Temp/inputFile.txt");
我在D：驱动器中创建了“Temp”文件夹并且代码执行成功。