Collections排序Java

Question

这种错？它不能正常工作。

public List<LibRegistration> getLibraryRegistrationsSortedByTypeAndName() 
    { 
     List<LibRegistration> l = getLibRegs(); 
     Collections.sort(l, new Comparator<LibRegistration>() { 
      public int compare(LibRegistration o1, LibRegistration o2) { 
       return o1.getLibraryType().compareTo(o2.getLibraryType()) != 0?o1.getLibraryType().compareTo(o2.getLibraryType()):o1.getLibraryName().compareTo(o2.getLibraryName()); 
      } 
     }); 
     return l; 
    } 

Answer 1

没有错，更清晰：

 public int compare(LibRegistration o1, LibRegistration o2) { 
      int cmp = o1.getLibraryType().compareTo(o2.getLibraryType()); 
      if (cmp == 0) 
       cmp = o1.getLibraryName().compareTo(o2.getLibraryName()); 
      return cmp; 
     } 

虽然空不允许的，良好的compareTo定义。