[英]Formatting Java Output Like a Table
I am attempting to output information regarding students stored by my program in a tabular-like format as \\t does not always provide the correct spacing. 我试图以类似于表格的格式输出关于我的程序存储的学生的信息,因为\\ t并不总是提供正确的间距。 In order to do so, I came across this question and have attempted to enable a similar solution.
为了做到这一点,我遇到了这个问题并试图启用类似的解决方案。 However, I am obtaining errors with the format lines in my code when I attempt to execute it as such.
但是,当我尝试执行它时,我在代码中获取格式行的错误。
public void displayStudents (){
System.out.println ("\n-----------------------------");
System.out.println ("Email System - Display Students");
System.out.println ("-----------------------------");
System.out.format("%10s%15d%15s%15s%20s", "Grade", "Last Name", "First Name", "Student Number", "Parent Email");
StudentNode current = top;
while (current != null){
Student read = current.getStudentNode();
System.out.format ("%10s%15d%15s%15s%20s", ""+read.getClass(), read.getLastName(), read.getFirstName(), ""+read.getStudentNum(), read.getParentEmail());
//This will output with a set number of character spaces per field, giving the list a table-like quality
}
}//End of displayStudents
The goal of the code is to output in a manner similar to the following image. 代码的目标是以类似于下图的方式输出。
Please aid me in finding my error. 请帮助我找到我的错误。 Is there perhaps an alternatively method to perform this?
是否有一种替代方法可以执行此操作?
Thanks. 谢谢。
EDIT: The error(s) I am getting are 编辑:我得到的错误是
GradeException in thread "main" java.util.IllegalFormatConversionException: d != java.lang.String
at java.util.Formatter$FormatSpecifier.failConversion(Unknown Source)
at java.util.Formatter$FormatSpecifier.printInteger(Unknown Source)
at java.util.Formatter$FormatSpecifier.print(Unknown Source)
at java.util.Formatter.format(Unknown Source)
at java.io.PrintStream.format(Unknown Source)
at StudentList.displayStudents(StudentList.java:184)
at OnlineCommunications.emailOption(OnlineCommunications.java:403)
at OnlineCommunications.main(OnlineCommunications.java:451)
It should be noted that Grade is an integer and Long is a double. 应该注意,Grade是一个整数,Long是一个整数。
The error is because %d
is for numeric non-floating point values ( int
, long
, etc). 错误是因为
%d
用于数字非浮点值( int
, long
等)。
In the line where you print the titles, you have to use %XXs
(where XX is a number) since you're passing String
s as parameters: 在打印标题的行中,您必须使用
%XXs
(其中XX是数字),因为您将String
作为参数传递:
System.out.format("%10s%15s%15s%15s%20s",
"Grade", "Last Name", "First Name", "Student Number", "Parent Email");
In the line inside the while-loop
, you need to set %d
for the int
and long
variables, like Grade and Student Number, there's no need to convert it to String
using "" + intProperty
: 在
while-loop
内的行中,你需要为int
和long
变量设置%d
,比如Grade和Student Number,不需要使用"" + intProperty
将它转换为String
:
System.out.format ("%10d%15s%15s%15d%20s",
read.getClass(), read.getLastName(), read.getFirstName(),
read.getStudentNum(), read.getParentEmail());
Since it looks like you want to format the output to the left (and not to the right), you should add a hypen (-) symbol before the XX number: 由于看起来您想要将输出格式化为左侧(而不是右侧),您应该在XX号码之前添加一个超级( - )符号:
//similar for title
System.out.format ("%-10d%-15s%-15s%-15d%-20s",
read.getClass(), read.getLastName(), read.getFirstName(),
read.getStudentNum(), read.getParentEmail());
Note: I assumed read.getClass()
and read.getStudentNum()
would return the Grade
and Student number
values as int
or long
. 注意:我假设
read.getClass()
和read.getStudentNum()
会将Grade
和Student number
数值返回为int
或long
。
The problem is: 问题是:
10s %15d %15s%15s%20s
10s %15d %15s%15s%20s
should be: 应该:
10s %15s %15s%15s%20s
10s %15s %15s%15s%20s
This is because all of the input parameters are String
, so d
( which applies to integral types only ) is invalid. 这是因为所有输入参数都是
String
,因此d
( 仅适用于整数类型 )无效。
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