Question

我正在尝试通过bufferedreader存储一堆变量。我是Java的新手，并且坦率地说它并不完全理解它甚至做了什么，但我知道它接受来自用户的输入并且我试图让它为我存储一堆变量。这是代码：

// import required packages for the program, importing all classes from packages to be on the safe side
import java.io.*;
import java.util.*;
import java.text.*;

public class Example
{
// need to use throws IO Exception because we are dealing with input and output, simple main method will not suffice
public static void main(String[] args) throws IOException
{
    // declare department names as strings
    String department1;
    String department2;
    String department3;
    String department4;

    // declare number of employees in each department as ints
    int employees1;
    int employees2;
    int employees3;
    int employees4;

    // declare cost per employee in each department as doubles
    double cpe1;
    double cpe2;
    double cpe3;
    double cpe4;

    //declare sales in each department as doubles
    double sales1;
    double sales2;
    double sales3;
    double sales4;

    // declare in as a BufferedReader- used to gain input from the user
    BufferedReader in;
    in = new BufferedReader(new InputStreamReader(System.in));

    //get input from the user to define department names
    System.out.println("What is the name of department 1?");
    department1 = in.readLine();
    System.out.println("What is the name of department 2?");
    department2 = in.readLine();
    System.out.println("What is the name of department 3?");
    department3 = in.readLine();
    System.out.println("What is the name of department 4?");
    department4 = in.readLine();
    System.out.println("\n");

    //get input fromm the user to define number of employees
    System.out.println("How many employees are in department 1?");
    employees1 = in.readLine();
    System.out.println("How many employees are in department 2?");
    employees2 = in.readLine();
    System.out.println("How many employees are in department 3?");
    employees3 = in.readLine();
    System.out.println("How many employees are in department 4?");
    employees4 = in.readLine();
    System.out.printlin("\n");

    // get input from user to define cost per employee in each department
    System.out.println("What is the cost per employee in department 1?");
    cpe1 = in.readLine();
    System.out.println("What is the cost per employee in department 2?");
    cpe2 = in.readLine();
    System.out.println("What is the cost per employee in department 3?");
    cpe3 = in.readLine();
    System.out.println("What is the cost per employee in department 4?");
    cpe4 = in.readLine();

    // get input from user to define sales in each department
    System.out.println("What are the sales in department 1?");
    sales1 = in.readLine();
    System.out.println("What are the sales in department 2?");
    sales2 = in.readLine();
    System.out.println("What are the sales in department 3?");
    sales3 = in.readLine();
    System.out.println("What are the sales in department 4?");
    sales4 = in.readLine();

我一直收到一条错误消息，说我尝试运行程序时出现了不兼容的类型。再次，这是非常新的，所以任何简单的解释将非常感激。谢谢！

Answer 1

readLine方法返回String。这段代码甚至不会编译。如果您想获得int值，则需要调用示例Integer.parseInt(ln)，其中ln是您从输入中读取的行。类似地，如果您想获得double值，则需要调用示例Double.parseDouble(ln)，其中ln是您从输入中读取的行。

Answer 2

问题是类型之一;你有几种不同的数据类型，但你只阅读字符串。我会像java.util.Scanner这样使用 -

java.util.Scanner in = new java.util.Scanner(System.in);
System.out.println("What is the name of department 1?");
if (in.hasNextLine()) {
  department1 = in.nextLine();
}
// ...
System.out.println("How many employees are in department 1?");
if (in.hasNextInt()) {
    employees1 = in.nextInt();
}
// ...
System.out.println("What is the cost per employee in department 1?");
if (in.hasNextDouble()) {
  cpe1 = in.nextDouble();
}

Answer 3

看看Scanner Class这应该可以满足您的需求。它允许您以整数/字符串/双精度读入输入，而无需进行任何手动转换

Answer 4

in.readLine()产生一个String - 不能自动转换为int或double。考虑Integer.parseInt(string)。

Answer 5

readLine（）方法返回一个String。您正试图将该String存储在int和double变量中。包装类中有一些方法（如Integer和Double），用于从String转换为数字。

您也可以考虑使用Scanner类。

readline不接受Java输入

5 个答案: