Java 为什么我的方法只能阅读一行文字?
我有一个方法,可以读取文本文件的部分,该文件有4个部分:日期、名称、描述和金额Java 为什么我的方法只能阅读一行文字?,java,text,Java,Text,我有一个方法,可以读取文本文件的部分,该文件有4个部分:日期、名称、描述和金额 4/5/2018, gel, hair product, 20.00 4/4/2018, wax, hair product, 20.00 等等 我的问题是,我的方法只读取第1行,然后输出catch方法,表示找不到文件 public static void showRecordedExpense(String filename)throws IOException { String date = "";
4/5/2018, gel, hair product, 20.00
4/4/2018, wax, hair product, 20.00
等等
我的问题是,我的方法只读取第1行,然后输出catch方法,表示找不到文件
public static void showRecordedExpense(String filename)throws IOException {
String date = "";
String name = "";
String description = "";
double amount = 0.00;
try{
Scanner read = new Scanner(new File(filename));
while (read.hasNextLine()){
String oneLine = read.nextLine();
String[] parts = oneLine.split(",");
try {
date = parts[0];
name = parts[1];
description = parts[2];
amount = Double.parseDouble(parts[3]);
System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
"---------------", "---------------------");
System.out.printf("%15s%15s%15s%31s%n","Date", "Name", "Description","Amount");
System.out.printf("%15s%14s%33s%15s%n",date,name,description,amount);
System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
"---------------", "---------------------");
}catch (Exception e){
System.out.println("no");
} finally {
read.close();
}
}
}catch (Exception e){
System.out.println("The file could not be found");
}
}
编辑:
取出“最终工作”按钮。阅读有关“最终工作”的详细信息。当前,由于您与try/catch
配对的finally
,您正在循环的第一次迭代结束时关闭扫描仪。while
的下一次迭代由于您关闭了文件而无法再读取该文件,这就是它仅读取第一行的原因。考虑在“<代码> > 循环完成时取出最后关闭扫描仪。
try{
Scanner read = new Scanner(new File(filename));
while (read.hasNextLine()){
String oneLine = read.nextLine();
String[] parts = oneLine.split(",");
try {
date = parts[0];
name = parts[1];
description = parts[2];
amount = Double.parseDouble(parts[3]);
System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
"---------------", "---------------------");
System.out.printf("%15s%15s%15s%31s%n","Date", "Name", "Description","Amount");
System.out.printf("%15s%14s%33s%15s%n",date,name,description,amount);
System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
"---------------", "---------------------");
}catch (Exception e){
System.out.println("no");
}
}
read.close();
}catch (Exception e){
System.out.println("The file could not be found");
}
有关最终如何工作的详细信息,请阅读。当前,由于您与try/catch
配对的finally
,您正在循环的第一次迭代结束时关闭扫描仪。while
的下一次迭代由于您关闭了文件而无法再读取该文件,这就是它仅读取第一行的原因。考虑在“<代码> > 循环完成时取出最后关闭扫描仪。
try{
Scanner read = new Scanner(new File(filename));
while (read.hasNextLine()){
String oneLine = read.nextLine();
String[] parts = oneLine.split(",");
try {
date = parts[0];
name = parts[1];
description = parts[2];
amount = Double.parseDouble(parts[3]);
System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
"---------------", "---------------------");
System.out.printf("%15s%15s%15s%31s%n","Date", "Name", "Description","Amount");
System.out.printf("%15s%14s%33s%15s%n",date,name,description,amount);
System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
"---------------", "---------------------");
}catch (Exception e){
System.out.println("no");
}
}
read.close();
}catch (Exception e){
System.out.println("The file could not be found");
}
你的文件存储在哪里?filename
的值是多少?我的文件存储在Intellij的src中,名称是expenses.txt在它读取了最后的第一行之后,您正在关闭扫描仪文件名的值是多少?您正在隐藏异常类型、消息和堆栈跟踪,这将告诉您问题所在。不要捕捉异常。捕获您期望的异常,并正确处理该异常。打印异常的堆栈跟踪。文件存储在哪里?filename
的值是多少?我的文件存储在Intellij的src中,名称是expenses.txt在它读取了最后的第一行之后,您正在关闭扫描仪文件名的值是多少?您正在隐藏异常类型、消息和堆栈跟踪,这将告诉您问题所在。不要捕捉异常。捕获您期望的异常,并正确处理该异常。打印异常的堆栈跟踪。