数组在main方法/类之外的单独类中

Question

我一直收到这个错误，它是关于在数组解除后需要括号的。

我不知道该怎么做。我想创建一个不在我的main方法中的数组。我希望数组是用子类填充的超类型。 这是我的代码

public class ArrayTest {

Employee [] employees = new Manager[2];
employees[0]= new Manager("Thomas", "Cummings");

}


public class Manager extends Employee{
private int employees;

public Manager() {
    super();
    employees = 0;
}

public Manager(int employees) {
    super();
    this.employees = employees;
}

public Manager(String f_name, String l_name) {
    super(f_name, l_name);
}

public Manager(String f_name, String l_name, int employees) {
    super(f_name, l_name);
    this.employees = employees;
}

public int getEmployees() {
    return employees;
}

public void setEmployees(int employees) {
    this.employees = employees;
}

public void setManager(String f_name, String l_name){
    this.setF_name(f_name);
    this.setL_name(l_name);
}

public void setManager(String f_name, String l_name, int employees){
    this.setF_name(f_name);
    this.setL_name(l_name);
    this.employees = employees;
}
@Override
public String toString(){
    return "\nName " + getF_name() + " " + getL_name() +
            "\nEmployee ID " + getEmp_id() + 
            "\nNum of employees " + getEmployees();
}
}


public class Employee {

private String f_name, l_name;
private static long emp_id = 001;

public Employee(){
    f_name = "";
    l_name = "";
    emp_id ++;
}
public Employee(String f_name, String l_name) {
    this.f_name = f_name;
    this.l_name = l_name;
    emp_id ++;
}
public String getF_name() {
    return f_name;
}
public void setF_name(String f_name) {
    this.f_name = f_name;
}
public String getL_name() {
    return l_name;
}
public void setL_name(String l_name) {
    this.l_name = l_name;
}
public long getEmp_id() {
    return emp_id;
}
public void setEmp_id(long emp_id) {
    Employee.emp_id = emp_id;
}

public String toString(){
    return "\nName " + getF_name() + " " + getL_name() +
            "\nEmployee ID " + getEmp_id();
}
}

Answer 1

错误的原因如下：

employees[0]= new Manager("Thomas", "Cummings");

因为你不能将可执行语句放在代码块（方法，块，构造函数）之外的java类中。

解决此问题的一种方法是在构造函数中移动初始化语句：

public class ArrayTest {

Employee [] employees = new Manager[2];

public ArrayTest() {
    employees[0]= new Manager("Thomas", "Cummings");
}

}

Answer 2

employees[0]= new Manager("Thomas", "Cummings");

这是一个需要放在适当的可执行块（方法，构造函数，初始化块）中的语句