时间戳

首页 > 解决方案 > 如何拆分多行并将它们添加到arraylist

java - 如何拆分多行并将它们添加到arraylist

问题描述

我在从 txt 文件中分离信息时遇到任何问题，将该信息添加到列表并使用该信息创建对象

此应用程序的数据文件将是一个逗号分隔（每条数据将由一个逗号分隔）的纯文本文件。为了标记成绩类型（实验室、项目和测试成绩）的差异，将包含一个空数据字段。文件的第一行将包含练习的可能分数。学生 ID 将是字符串。 

示例 ID,名字,姓氏,10,10,10,,100,100,,100

三个实验室（每个值 10 分） 

两个项目（每个100分） 

一项测试（价值 100 分） 

txt文件设置如下

ID,名字,姓氏,10,10,10,,100,100,,100

1234,乔,学生,10,8,9,,100,90,,100

5678,另一个,学生,7,7,7,,75,75,,75

9012,Yet,Another,10,10,10,,65,70,,50

对象类

public class Student {
private String identifcation;
private String firstName;
private String lastName;
private List labs;
private List project;
private List test;

public Student(String identifcation, String firstName, String lastName, List<Integer> labs, List<Integer> projects, List<Integer> test) {
    this.identifcation = identifcation;
    this.firstName = firstName;
    this.lastName = lastName;
    this.labs = labs;
    this.project = projects;
    this.test = test;
    }
}

类中的 readfile 方法

public List<Student> decode() {

    List<Student> students = new ArrayList<Student>();

    while (this.scan.hasNext()) {
        List<Integer> labs = new ArrayList<Integer>();
        List<Integer> projects = new ArrayList<Integer>();
        List<Integer> tests = new ArrayList<Integer>();

        String identifcation = this.scan.next();
        String firstName = this.scan.next();
        String lastName = this.scan.next();

//help  int lab =      the labs
//help  labs.add(lab); should add the 3 labs
//help  int project = 
//help  projects.add(project); should add the 2 projects
//help  int test = 
//help  tests.add(test); should add the 1 test

        System.out.println(identifcation);
        System.out.println(firstName);
        System.out.println(lastName);

        System.out.print(this.scan.nextLine());         

        Student real = new Student(identifcation, firstName, lastName, labs, projects, tests);
        students.add(real);
    }
    return students;
}

打印语句给了我一个输出

身份证，第一

姓名，姓氏

名称,10,10,10,,100,100,,100

1234,乔,学生,7,8,9,,80,90,,100

5678,另一个,学生,7,7,7,,75,75,,75

9012,Yet,Another,10,10,10,,65,70,,50

他们应该给

ID

名

姓

ETC..

标签： javaarrayseclipsefile

解决方案

I'd recommend going line by line in with the scanner - store the entire line as an input string. Then you could split up the line using a function like the Java string.split(), putting in ',' for the separator option. This would allow you to return the string in an array, which you can then sort into your arraylist however you wanted. See here for more detail on the split() function

example (might want to check in a compiler):

Scanner in = new Scanner(System.in);
String input;

//define arraylist outside of loop :-)
 ArrayList<String> arraylist1 = new ArrayList<>();
 ArrayList<String> arraylist2 = new ArrayList<>();


(while in.hasNext()){
    //store entire line
    input= in.nextLine();

     //Splits input string with , stores each string in an index position in data[]
     String[] data = input.split(",");

     arraylist1.add(data[0]);
     arraylist2.add(data[1]);
     //etc....
}

Hope this helps!

推荐阅读