Comparator and Comparable are the same
They are all an interface of java, and are used to compare the size of custom classes,
What is a custom class: such as public class Person{ String name; int age }.
When we have such a personList, which contains person1, person2, person3….., we can’t get the expected result by using CollectIons.sort( personList ). At this time, someone must ask, why can we sort a character What about the string list:
For example, StringList{“hello1â€, “hello3â€, “hello2â€}, CollectIons.sort(stringList) can get the correct sorting, that is because the String object has already implemented the Comparable interface for us, so if our Person wants to sort, Also implement a comparator.
Difference Between Comparator and Comparable
Comparable
Comparable is defined inside the Person class:
public class Persion implements Comparable {..Compare the size of Person..},
Because the comparator has been implemented, then our Person is now an object that can compare the size. Its comparison function is exactly the same as that of String, and it can be used to compare the size anytime, anywhere, because the Person itself now has a size. CollectIons.sort(personList) can get the correct result.
Comparator
Comparator is defined outside of Person. At this time, the structure of our Person class does not need to be changed, such as
public class Person{ String name; int age },
Then we define another comparator:
public PersonComparator implements Comparator() {..Compare the size of Person..},
How to compare the size of two Persons is implemented in PersonComparator. So, in this way, when we want to sort a personList, we need to pass PersonComparator in addition to passing personList, because how to compare Person The size is implemented in PersonComparator, such as:
CollecTIons.sort( personList , new PersonComparator() ).
Instances of Comparator and Comparable
Comparable:
To implement the Comparable interface, you need to override the compareTo method, and implement the comparison in the compareTo method:
public class Person implements Comparable {
String name;
int age
public int compareTo(Person another) {
int i = 0;
i = name.compareTo(another.name); // compare using strings
if(i == 0) { // If the names are the same, compare the age, return the result of comparing the age
return age - another.age;
} else {
return i; // The names are different, return the result of comparing the names.
}
}
}
At this point we can sort it directly with Collections.sort( personList ).
Comparator:
Implementing Comparator requires overriding the compare method:
public class Person{
String name;
int age
}
class PersonComparator implements Comparator {
public int compare(Person one, Person another) {
int i = 0;
i = one.name.compareTo(another.name); // compare using strings
if(i == 0) { // If the names are the same, compare the age and return the result of comparing the age
return one.age - another.age;
} else {
return i; // The names are different, return the result of comparing the names.
}
}
}
Collections.sort( personList , new PersonComparator()) can sort it
4: Summary
The two methods have their own advantages and disadvantages. It is simple to use Comparable. As long as the object that implements the Comparable interface directly becomes a comparable object, but the source code needs to be modified, the advantage of using Comparator is that it does not need to modify the source code, but implements another comparison. When a custom object needs to be compared, pass the comparator and the object together to compare the size, and in the Comparator, users can implement complex and general logic to match some comparisons Simple objects, so you can save a lot of repetitive work.
The Cleaning Blade is a kind of Printer Accessories.
The cartridge is irradiated by laser beam to adsorb toner, and then the toner is hot pressed by fixing roller for printing. In this process, there will be part of toner residual, which can not be "granules returned to the warehouse"; Automatic cleaning function is not adsorbed new toner particles and directly print, will remain toner away, fully ensure the next printing effect. And the Plate-Grid plays an important role. When high voltage generator to a high voltage electrode, wire electrode with reseau formed between a strong electric field, and release the corona, wire electrode and the photosensitive drum ionizes the air between the air ions migrate to the drum surface, make the photoconductor (drum) surface is full of charge, so can spare toner "adsorption to warehouse", so as to save toner, The purpose of reducing environmental pollution.
Printer Cleaning Blade,Carbon Powder Scraping,Cleaning Transfer Roller,Carbon Powder Scraping Cleaning Blade
SHAOXING HUALI ELECTRONICS CO., LTD. , https://www.cnsxhuali.com