所以我想阅读一个文本文件，但由于一些奇怪的原因，它无法找到该文件。我之前使用过这些方法，因此我不知道为什么这不起作用有人可以帮帮我吗？
抱歉，我遗漏了一大段信息，它可以在写入文件时找到文件，但是当它从中读取文件时却找不到。感谢你们所有人的帮助，抱歉浪费你的时间提问，我不需要答案......再次抱歉。
“Assets.txt”既在项目的根文件夹中，也在src / assetregistry中
程序运行时“Assets.txt”将出现在那里
我得到的是来自readFromFile（）方法中的catch异常的JOption messege
根据assetRegistry的属性，工作目录是
"C:\Users\Justin\Documents\NetBeansProjects\assetregistry\src\assetregistry"
感谢所有帮助过的人，尤其是Chris和Andrew Thompson。该程序现在可以使用，以下是更新版本。如果您愿意，可以随意复制。这真的是一个简单的程序。
package assetregistry;
import java.io.IOException;
import javax.swing.JOptionPane;
public class Assetregistry {
public static void main(String[] args) throws IOException {
new Assetregistry();
}
assetArray aa = new assetArray();
public Assetregistry() throws IOException {
aa.readFromFile ();
char choice = 'Z';
while (choice != 'X') {
choice = menu();
options(choice);
}
}
public char menu() {
char ch = JOptionPane.showInputDialog("\t" + "Welcome to asset registry. Please input your choice" + "\n" + "A: Enter new asset" + "\n" + "B: Calculate depreciation and display" + "\n" + "X: Exit").toUpperCase().charAt(0);
return ch;
}
private void options(char c) throws IOException {
switch (c) {
case 'A':
aa.enterAsset();
break;
case 'B':
aa.calculate();
break;
case 'X':
System.exit(0);
break;
}
}
}
package assetregistry;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import javax.swing.JOptionPane;
public class assetArray {
asset[] aArr = new asset[100];
private double year;
private double month;
private int count = 0;
Assetregistry AR;
String home = System.getProperty("user.home");
File userHome = new File(home);
File file = new File(userHome,"Assets.txt");
public assetArray() throws IOException {
}
public void enterAsset() throws IOException {
int choice = JOptionPane.YES_OPTION;
while (choice == JOptionPane.YES_OPTION) {
String name = JOptionPane.showInputDialog("Enter asset name");
double costP = Double.parseDouble(JOptionPane.showInputDialog("Enter the cost price of the asset"));
int lSpan = Integer.parseInt(JOptionPane.showInputDialog("Enter the amount of years you wish to keep the asset"));
double mBought = Double.parseDouble(JOptionPane.showInputDialog("Enter the month the asset was bought (As a number)"));
double yBought = Double.parseDouble(JOptionPane.showInputDialog("Enter the year the asset was bought"));
double depr = (1.00 / lSpan * 100.00);
aArr[count] = new asset(name, costP, lSpan, yBought, mBought, depr);
PrintWriter pw = new PrintWriter(new FileWriter(file, true));
pw.println(aArr[count].toString());
pw.close();
count++;
choice = JOptionPane.showConfirmDialog(null, " Do you want to enter another asset?", " Enter another asset?", JOptionPane.YES_NO_OPTION);
}
}
public void calculate() {
String name;
int lSpan;
double ybought;
double mbought;
double pValue;
double Rate;
double deprExp;
double numYears;
double fValue;
double accDepr;
String[] mnth = new String[12];
mnth[0] = "January";
mnth[1] = "February";
mnth[2] = "March";
mnth[3] = "April";
mnth[4] = "May";
mnth[5] = "June";
mnth[6] = "July";
mnth[7] = "August";
mnth[8] = "September";
mnth[9] = "October";
mnth[10] = "November";
mnth[11] = "December";
if (count > 0) {
year = Integer.parseInt(JOptionPane.showInputDialog("Enter the year you wish to calculate depreciation for"));
month = Integer.parseInt(JOptionPane.showInputDialog("Enter the month you wish to calculate depreciation for"));
int m = (int) month;
int y = (int) year;
System.out.println("Asset regestry" + "\t" + mnth[m-1] + " " + y);
for (int i = 0; i < count; i++) {
name = aArr[i].getName();
lSpan = aArr[i].getLifeSpan();
ybought = aArr[i].getyBought();
mbought = aArr[i].getmBought();
pValue = aArr[i].getCostP();
Rate = aArr[i].getDeprR();
int m2 = (int) mbought;
int y2 = (int) ybought;
deprExp = pValue - (pValue * ((1.00 - ((Rate))) * 1.00 / 100.00));
numYears = (year + (month / 12.00)) - (ybought + mbought / 12.00);
fValue = pValue * (1.00 - (((Rate) * (numYears)) / 100.00));
if (fValue <= 0.00) {
fValue = (int) 1;
}
accDepr = pValue - fValue;
System.out.println("\n" + "Asset: " + name);
System.out.println("Life span: " + lSpan + "yrs");
System.out.println("Cost price: " + "R" + pValue);
System.out.println("Date acquired: " + mnth[m2-1] + " " + y2);
System.out.println("Depreciatin rate (p.a.): " + Rate + "%");
System.out.println("Depreciation(p.a.): R" + deprExp);
System.out.println("Accumulated depreciation: R" + accDepr);
System.out.println("Current book value: R" + fValue);
System.out.println("_________________________________________");
}
} else {
JOptionPane.showMessageDialog(null, "There are no assets in memory", "NO ASSETS!", JOptionPane.ERROR_MESSAGE);
}
}
/**
*
*/
public void readFromFile() {
String line = "";
try {
BufferedReader fr = new BufferedReader(new FileReader(file));
line = fr.readLine();
while (line != null) {
StringTokenizer stk = new StringTokenizer(line, "#");
String name = stk.nextToken();
double costP = Double.parseDouble(stk.nextToken());
int lSpan = Integer.parseInt(stk.nextToken());
double yBought = Double.parseDouble(stk.nextToken());
double mBought = Double.parseDouble(stk.nextToken());
double deprR = Double.parseDouble(stk.nextToken());
aArr[count] = new asset(name, costP, lSpan, yBought, mBought, deprR);
count++;
line = fr.readLine();
}
fr.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "There is a file missing.", "FILE MISSING!", JOptionPane.ERROR_MESSAGE);
}
}
}
package assetregistry;
/**
*
* @author Justin
*/
public class asset {
private String name;
private double costP;
private int lifeSpan;
private double yBought;
private double mBought;
private double deprR;
public asset(){
}
public asset(String name, double costP, int lifeSpan, double yBought, double mBought, double deprR) {
this.name = name;
this.costP = costP;
this.lifeSpan = lifeSpan;
this.yBought = yBought;
this.mBought = mBought;
this.deprR = deprR;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getCostP() {
return costP;
}
public void setCostP(double costP) {
this.costP = costP;
}
public int getLifeSpan() {
return lifeSpan;
}
public void setLifeSpan(int lifeSpan) {
this.lifeSpan = lifeSpan;
}
public double getyBought() {
return yBought;
}
public void setyBought(double yBought) {
this.yBought = yBought;
}
public double getmBought() {
return mBought;
}
public void setmBought(double mBought) {
this.mBought = mBought;
}
public double getDeprR() {
return deprR;
}
public void setDeprR(double deprR) {
this.deprR = deprR;
}
@Override
public String toString ()
{
String stg = "";
stg += name + "#" + costP + "#" + lifeSpan + "#" + yBought + "#" + mBought + "#" + deprR + "#";
return stg;
}
}
答案 0 :(得分：2)
String home = System.getProperty("user.home");
System.out.println("User home directory is: " + home);
File userHome = new File(home);
// Put files in a known and reproducible path!
File file = new File(userHome, "Assets.txt");
答案 1 :(得分：2)
这取决于您在文件系统中放置“Assets.txt”的位置。如果您从netbeans内部运行代码，则行：
File file = new File("Assets.txt");
将在项目的根文件夹中查找该文件，例如* / NetBeansProjects / INSERT_PROJECT_NAME /（如果你不是那么它将在运行应用程序的同一目录中查找文件）。我注意到你有这行：
URL url = AR.getClass().getResource("/Assets.txt");
但你永远不会在你的代码中使用url。您是否尝试在与“Assetregistry”类相同的目录中查找该文件，并忘记使用url指定位置？如果是这种情况，则从名称的开头删除“/”并构造如下文件：
URL url = Assetregistry.class.getResource("Assets.txt");
File file = new File(url.toURI());
希望这有帮助:)