Briefly describe the abstraction and encapsulation, which has some function for you to learn Java. Briefly describe java

Briefly describe the abstraction and encapsulation, which has some function for you to learn Java. Briefly describe java

As a beginner in Java, you may have some one-sided or even some incorrect understanding of Java. You may wish to watch it here !!!

God knows why I chose to learn programming. I don't like programming. But now that I have learned, I will continue to study hard and share some learning experience here.

Access modifier:

1. Common Access modifiers:

Public

Private

Protect Protection

Public can be used by everyone, private can be used by themselves, protect is a bag.

2. Automatically correct the shortcut key ctrl + 1 (Note: Search for the MyEclipse shortcut key Daquan, you can find all the shortcut keys)

The real usage also requires your own experience in the environment.

3. object-oriented, such:

First set up a Student Class 1:

1 package cn. curry. day01; 2 3 public class Student1 {4 private String name; 5 private int age; 6 public String getName () {7 return name; 8} 9 public void setName (String name) {10 this. name = name; 11} 12 public int getAge () {13 return age; 14} 15 public void setAge (int age) {16 17 if (age <= 16) {18 this. age = age; 19} 20 else {21 this. age = age; 22 System. out. println ("the age cannot be more than 16 years old! "); 23} 24 25} 26 public void studentInfo () 27 {28 if (this. age> 16) {29 return; 30} 31 System. out. println ("Student name" + this. getName () + ", age:" + this. getAge (); 32} 33 34}

Set up a Student Category 2

1 package cn. curry. day01; 2 3 public class Student2 {4 private String name; 5 private int age; 6 private String sex; 7 private String work; 8 public Student2 (String sex, String work) 9 {10 this. setSex (sex); 11 this. setWork (work); 12} 13 public Student2 (String name, int age, String sex, String work) 14 {15 16 this. setName (name); 17 this. setAge (age); 18 this. setSex (sex); 19 this. setWork (work); 20} 21 22 public String getName () {23 return name; 24} 25 public void setName (String name) {26 this. name = name; 27} 28 public int getAge () {29 return age; 30} 31 public void setAge (int age) {32 this. age = age; 33} 34 public String getSex () {35 return sex; 36} 37 public void setSex (String sex) {38 this. sex = sex; 39} 40 public String getWork () {41 return work; 42} 43 public void setWork (String work) {44 this. work = work; 45} 46 public void myself () {47 System. out. println ("My name is" + this. getName () + ", age is" + this. getAge () + ", gender is" + this. getSex () + ", Major" + this. getWork (); 48} 49 50}

These two types only display student information, but some methods are different. Classes are abstract. A class can have n objects, and an object can only come from one class.

4. One-time generation of all fields

The cursor stays behind the last field, then alt + shift + s, then r + alt + a, and then alt + s

5. Quick Method for creating classes ctrl + n

Format the code block ctrl + shift + f

6. Constructor

The method name is the same as the class name. No return value is returned, and no void is returned!

7. Method overloading: in the same class, the method name is the same and the parameter list is different. It is irrelevant to the return value and access modifier! ,

8. static keywords

Modify a class member. All classes share one content.

Static code block

1 package cn. curry. day01; 2 3 public class Dog {4 private String name; 5 private String age; 6 public String getName () {7 return name; 8} 9 public void setName (String name) {10 this. name = name; 11} 12 public String getAge () {13 return age; 14} 15 public void setAge (String age) {16 this. age = age; 17} 18 public static Cat [] cats;
// Static code block 19 static {20 cats = new Cat [2]; 21 System. out. println (); 22 cats [0] = new Cat (); 23 cats [0]. setName ("rhubarb"); 24 cats [1] = new Cat (); 25 cats [1]. setName ("yellow"); 26} 27 28}

9. usage of this

The basic things are all there. Please follow the next blog to expand things in the future!