Question

public static void main(String[] args) {
    staples[] stemp = new staples[8];
    int j;

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        for (j = 0; j < 8; j++) {
            System.out.print("Enter your name : ");
            stemp[j].setName(reader.readLine());

            System.out.println("Enter your age : ");
            stemp[j].setAge(Integer.parseInt(reader.readLine()));
        }

        for (j = 0; j < 8; j++) {
            System.out.print("Employee number:" + "j:" + "name:" + stemp[j].getName() + " Age:" + stemp[j].getAge());
        }

        reader.close(); // VERY IMPORTANT TO CLOSE

        System.out.println("Program ended");
    } catch (java.io.IOException ex) {
        System.out.println("Error is " + ex.getMessage());
    }
}

我正在尝试将值传递给数组对象stemp，它具有两个属性name和age。将值输入到数组的正确语法是什么？上面的语法是否正确？

Answer 1

您需要添加stemp[j] = new staples();，否则您将获得NPE。

在Java中创建数组时，JVM会为对象分配N 引用的空间，但不会为对象本身分配空间。您需要使用new运算符逐个分配这些。

for ( j=0;j<8;j++)
{
     stemp[j] = new staples();
     System.out.print("Enter your name : ");
     stemp[j].setName(reader.readLine());
     System.out.println("Enter your age : "); 
     stemp[j].setAge(Integer.parseInt(reader.readLine()));
}

Answer 2

public static void main(String[] args) {
    staples[] stemp = new staples[8];
    int j;

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        for (j = 0; j < 8; j++) {
            System.out.print("Enter your name : ");
            stemp[j] = new staples();
            stemp[j].setName(reader.readLine());

            System.out.println("Enter your age : ");
            stemp[j].setAge(Integer.parseInt(reader.readLine()));
        }

        for (j = 0; j < 8; j++) {
            System.out.print("Employee number:" + "j:" + "name:" + stemp[j].getName() + " Age:" + stemp[j].getAge());
        }

        reader.close(); // VERY IMPORTANT TO CLOSE

        System.out.println("Program ended");
    } catch (java.io.IOException ex) {
        System.out.println("Error is " + ex.getMessage());
    }
}

基本java - 将值传递给对象数组

2 个答案: