基于两个参数同时收集排序 [英] Collection sorting in basis of two parameters simultaneously

问题描述

我有一个类有两个日期字段说：

  class TestData {
 Date activation; 
日期timeStamp; 
} 
  

我想根据 activation 日期，如果它们相等，则基于 timestamp 即max（激活）和max（timeStamp）。

代码我试过的只有fetch max（激活）

  public class CollectionSort {
 
 public static void main（String [] args）{
 List< TestData> testList = new ArrayList< TestData>（）; 
 
 Collections.sort（testList，new Comparator< TestData>（）{
 
 @Override 
 public int compare（TestData t1，TestData t2）{
 int result = 0; 
 if（t1.getActivation（）。before（t2.getActivation（）））{
 result = 1; 
} 
返回结果; 
} 
}）; 
 System.out.println（First object is+ testList.get（0））; 
} 
} 
  

任何帮助将非常感激。

感谢

解决方案

b

  Collections.sort（yourList，new Comparator< TestData>（）{
 public int compare（TestData o1，TestData o2）{
 int date1Diff = o1.getActivation（）。compareTo（o2.getActivation（））; 
 return date1Diff == 0？
 o1.geTimestamp（）。compareTo（o2.getTimestamp（））：
 date1Diff; 
} 
}）; 
  

I have a class with two date fields say:

class TestData {
    Date activation;
    Date timeStamp;
}

I want to sort the list of the above class on basis of activation date and if they are equal then on basis of timestamp i.e. max(activation) and max(timeStamp).

Code I tried is as follws which only fetch max(activation)

public class CollectionSort {

    public static void main(String[] args) {
        List<TestData> testList = new ArrayList<TestData>();

        Collections.sort(testList, new Comparator<TestData>() {

            @Override
            public int compare(TestData t1, TestData t2) {
                int result = 0;
                if (t1.getActivation().before(t2.getActivation())) {
                        result = 1;
                }
                return result;
            }
        });
        System.out.println("First object is " + testList.get(0));
    }
}

Any help would be greatly appreciated.

Thanks

解决方案

This would do it.!

        Collections.sort(yourList, new Comparator<TestData>() {    
            public int compare(TestData o1, TestData o2) {
                int date1Diff = o1.getActivation().compareTo(o2.getActivation());
                return date1Diff == 0 ? 
                        o1.geTimestamp().compareTo(o2.getTimestamp()) :
                        date1Diff;
            }               
        });

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