public final Class<?> getClass(){}
返回引用中存储的实际对象类型。
应用:通常用与判断两个引用中实际存储对象类型是否一致
package com.cnblogs; //本类用于实现 public class Application { public static void main(String[] args) { Student student = new Student("张三",20); Student student2 = new Student("李四",21); Class aClass1 = student.getClass(); Class aClass2 = student2.getClass(); if(aClass1 == aClass2){ System.out.println("student和student2属于同一类型"); }else{ System.out.println("student和student2不属于同一类型"); } /* student和student2属于同一类型 */ } }
package com.cnblogs; /* student类 */ public class Student{ private String name; private int age; public Student(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } }
getClass()方法是获得调用该方法的对象的类;getClass().getName()可以得到该类的路径;
通过getClass()方法得到该对象类Class后,可以通过Class获取这个类中的相关属性和方法;
package com.cnblogs; //本类用于实现 public class Application { public static void main(String[] args) { Student student = new Student("张三",20); Student student2 = new Student("李四",21); System.out.println(student.hashCode());//460141958 System.out.println(student2.hashCode());//1163157884 Student student3 = student; System.out.println(student3.hashCode());//460141958 } }
package com.cnblogs; /* student类 */ public class Student{ private String name; private int age; public Student(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } }
package com.cnblogs; //本类用于实现 public class Application { public static void main(String[] args) { Student student = new Student("张三",20); Student student2 = new Student("李四",21); //重写toString方法前 System.out.println(student.toString());//com.cnblogs.Student@1b6d3586 System.out.println(student2.toString());//com.cnblogs.Student@4554617c //重写toString方法后 System.out.println(student.toString());//张三:20 System.out.println(student2.toString());//李四:21 } }
package com.cnblogs; /* student类 */ public class Student{ private String name; private int age; public Student(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } //重写toString方法 public String toString(){ return name +":"+ age; } }
package com.cnblogs; //本类用于实现 public class Application { public static void main(String[] args) { Student student = new Student("张三",20); Student student2 = new Student("李四",21); //equals方法重写之前 System.out.println(student.equals(student2));//false Student student3 = new Student("王五", 18); Student student4 = new Student("王五", 18); System.out.println(student3.equals(student4));//false //equals方法重写之后 System.out.println(student.equals(student2));//false System.out.println(student3.equals(student4));//true } }
package com.cnblogs; /* student类 */ public class Student{ private String name; private int age; public Student(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } //重写equls方法 public boolean equals(Object obj){ //判断两个对象是否为同一个引用 if(this == obj){ return true; } //判断obj是否为null if(obj == null){ return false; } //判断是否是同一个类型 if(obj instanceof Student){ //强制类型转换 Student s = (Student) obj; //比较属性 if(this.name.equals(s.getName()) && this.age == s.getAge()){ return true; } } return false; } }
package com.cnblogs; //本类用于实现 public class Application { public static void main(String[] args) { Student student = new Student("张三",20); Student student2 = new Student("李四",21); new Student("李四1",21); new Student("李四2",21); new Student("李四3",21); new Student("李四4",21); new Student("李四5",21); //回收垃圾 System.gc(); System.out.println("垃圾回收了"); /* 垃圾回收了 李四5垃圾被回收了!!! 李四4垃圾被回收了!!! 李四3垃圾被回收了!!! 李四2垃圾被回收了!!! 李四1垃圾被回收了!!! */ } }
package com.cnblogs; /* student类 */ public class Student{ private String name; private int age; public Student(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } //重写finalize方法 protected void finalize()throws Throwable{ System.out.println(this.name + "垃圾被回收了!!!"); } }