在java中调用匿名类方法

Question

我正在尝试编写以下问题的代码： 用于获取empno，DOB和少数员工工资的WAP。 编写两个匿名内部类，一个实现按照其DOB排序员工的接口，另一个匿名内部类扩展一个类，按员工薪水对员工进行排序。 我的代码是：

//required import statements 

public class OuterClass { 
    private int empno; 
    private String DOB; 
    private int salary; 

    public OuterClass() { 
     // TODO Auto-generated constructor stub 
    } 

    public OuterClass(int empn, String dob, int sal) { 
     //code for paramaterized constructor 
    } 

    public static void main(String[] args) { 
     Scanner sc = new Scanner(System.in); 
     List<OuterClass> list = new ArrayList<OuterClass>(); 
     while (true) { 
      //code for input from user and adding it in list 
     } 
    } 

    Employee abc = new Employee() { 
     @Override 
     void SalarySort(List<OuterClass> l) { 
      Collections.sort(l, new Comparator<OuterClass>() { 
       public int compare(OuterClass e1, OuterClass e2) { 
        return e1.salary - e2.salary; 
       } 
      }); 
      Iterator<OuterClass> itr = l.iterator(); 
      while (itr.hasNext()) { 
       OuterClass employee = (OuterClass) itr.next(); 
       System.out.println("Emp no : " + employee.empno + " Emp dob : " 
         + employee.DOB + " Emp Salary : " + employee.salary); 
      } 
     } 

    }.SalarySort(list);// compile error : create local field list 

} 

class Employee { 
    void SalarySort(List<OuterClass> l) { 

    } 
} 

我的问题是，我不能称之为匿名类员工的方法SalarySort，如何解决这个问题呢？

Answer 1

如果裁减非编译部分的代码，把它归结为

Employee abc = new Employee() { ... }.SalarySort(list); 

所以，你要初始化变量abc，Employee类型的，由返回的值方法SalarySort()，它返回void。

你只是想

Employee abc = new Employee() { ... }; 
abc.SalarySort(list); 

或

new Employee() { ... }.SalarySort(list); 

BTW，读取编译器错误消息可能会有助于发现问题。

另一个问题是，上面的代码应该在主方法中，其中list被定义，而不是在它之外。另外，请尊重Java命名约定，并为您的类，方法和变量选择合适的名称。不要将员工的名字命名为非员工。不要将XxxInnerClass命名为不是内部类的东西。

Answer 2

这个怎么样？它使用匿名内部类实现一个接口，并且还扩展了一个类。

import java.util.Arrays; 
import java.util.Comparator; 

public class AnonymousInner 
{ 
int empNo; 
double salary; 
MyDate dateOfBirth; 
public AnonymousInner(int empNo, double salary, MyDate dateOfBirth) 
{ 
    this.empNo = empNo; 
    this.salary = salary; 
    this.dateOfBirth = dateOfBirth; 
} 

@Override 
public String toString() 
{ 
    return "\nEmployee = " + empNo + " Salary= " + salary + " DOB= " + dateOfBirth; 
} 
public static void main(String[] args) 
{ 
    AnonymousInner[] a = 
    {new AnonymousInner(1, 5000, new MyDate(15, 0, 1994)), new AnonymousInner(2, 4000, 
      new MyDate(15, 1, 1993)), new AnonymousInner(3, 5000, new MyDate(15, 0, 1995)), 
      new AnonymousInner(4, 6000, new MyDate(16, 0, 1994)), new AnonymousInner(5, 9000, 
        new MyDate(15, 1, 1994))}; 

    Arrays.sort(a, new Comparator<AnonymousInner>() //This creates anonymous class that implements an interface 
    { 

     @Override 
     public int compare(AnonymousInner o1, AnonymousInner o2) 
     { 

      return ((Double) o1.salary).compareTo(o2.salary); 
     } 
    }); 
    System.out.println("Sorting on Salary"); 
    for (AnonymousInner s : a) 
    { 
     System.out.println(s); 
    } 

    a = new sortDOB() 
    { 
    }.sort(a); //this creates Anonymous class that extends a class 

    System.out.println("\nSorting on DOB\n"); 
    for (AnonymousInner s : a) 
    { 
     System.out.println(s); 
    } 

} 

} 

class sortDOB 
{ 

public AnonymousInner[] sort(AnonymousInner[] x) 
{ 
    int size = x.length; 
    for (int i = 0; i < size; i++) 
    { 
     for (int j = 0; j < size - 1; j++) 
     { 
      int k = j + 1; 
      int compare = (x[j].dateOfBirth).compareTo(x[k].dateOfBirth); 
      if (compare == 1) 
      { 
       AnonymousInner temp = x[j]; 
       x[j] = x[k]; 
       x[k] = temp; 

      } 
     } 
    } 
    return x; 
} 
} 

class MyDate implements Comparable<MyDate> 
{ 
int year, month, day; 
public MyDate(int day, int month, int year) 
{ 
    this.year = year; 
    this.month = month; 
    this.day = day; 
} 

public MyDate() 
{ 
} 

@Override 
public String toString() 
{ 
    return day + "/" + month + "/" + year; 
} 

@Override 
public int compareTo(MyDate o2) 
{ 
    if (year == o2.year) 
    { 
     if (month == o2.month) 
     { 
      if (day == o2.day) 
      { 
       return 0; 
      } 
      else if (day < o2.day) 
      { 
       return -1; 
      } 
      else 
      { 
       return 1; 
      } 

     } 
     else if (month < o2.month) 
     { 
      return -1; 
     } 
     else 
     { 
      return 1; 
     } 
    } 
    else if (year < o2.year) 
    { 
     return 1; 
    } 
    else 
    { 
     return -1; 
    } 

} 
}