标签：log add cto support int creat prim false bad
Constructor
Object()
Method
Object clone() // protected shallow copy ，override it as public if the subclass use this method ，
// implement the Cloneable interface，just a mark
Creates and returns a copy of this object.
private String name; private int age; private int arr[]; private Heart h; @Override public Object clone() throws CloneNotSupportedException { return super.clone(); } People p = new People(); People p2 = (People)p.clone(); //Object 类实现的是浅拷贝，但是能对String，数组进行深拷贝 System.out.println(p); // H是一个类，引用类型，此时可看出进行了浅拷贝 System.out.println(p2); p2.setAge(100); p2.setName("hah"); int[] arr = {1,1,1}; p2.setArr(arr); p2.getH().setHealth("bad"); p2.getH().setJump(100); System.out.println("++++++++++++++++++++"); System.out.println(p2); System.out.println(p); // People [name=alex, age=0, arr=[1, 2, 3], h=Heart [jump=80, health=good]] // People [name=alex, age=0, arr=[1, 2, 3], h=Heart [jump=80, health=good]] // ++++++++++++++++++++ // People [name=hah, age=100, arr=[1, 1, 1], h=Heart [jump=100, health=bad]] // People [name=alex, age=0, arr=[1, 2, 3], h=Heart [jump=100, health=bad]]
public People clone() throws CloneNotSupportedException { People p = new People(); return p; } public People() { this("alex",0,new int[]{1,2,3}, new Heart(80, "good")); } public People(String name, int age, int[] arr, Heart h) { super(); this.name = name; this.age = age; this.arr = arr; this.h = h; } People [name=alex, age=0, arr=[1, 2, 3], h=Heart [jump=80, health=good]] People [name=alex, age=0, arr=[1, 2, 3], h=Heart [jump=80, health=good]] ++++++++++++++++++++ People [name=hah, age=100, arr=[1, 1, 1], h=Heart [jump=100, health=bad]] People [name=alex, age=0, arr=[1, 2, 3], h=Heart [jump=80, health=good]]
boolean equals() // return true if their address is equals , which isn‘t very useful
Indicates whether some other object is "equal to" this one.
public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; People other = (People) obj; if (age != other.age) return false; if (name == null) { if (other.name != null) return false; } else if (!name.equals(other.name)) return false; return true; } 等价于 public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; People other = (People) obj; return Objects.equals(this.name, other.name)&& this.age == other.age ; }
Class<?> getClass()
Returns the runtime class of this Object.
int hashCode() // the Object get the hash code according to the address
Returns a hash code value for the object
@Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + age; result = prime * result + ((name == null) ? 0 : name.hashCode()); return result; } 等价于 public int hashCode() { return Objects.hash(this.age, this.name); }
String toString() // the Object implements it by return the memory address
Returns a string representation of the object.
public String toString() { return "People [name=" + name + ", age=" + age + "]"; }
all the code above is the implement of subclass
java.util.Objects // the tools class for Object
boolean equals(Object a, Object b) // a,b can be null, which is important !
Returns true if the arguments are equal to each other(both null ) and false otherwise.
int hash(Object...values) // you need this when override the hashCode() method, see the code above
Generates a hash code for a sequence of input values.
标签：log add cto support int creat prim false bad
原文地址：http://www.cnblogs.com/YKang/p/7277139.html
