Java——集合的に行列を回転し、巡回します。
6794 ワード
* A:
*
* B:
* ,
* public Object[] toArray() ( ) 。
package com.wsq.bean;
// Student
public class Student {
private String name;
private int age;
public Student() {
super();
}
public Student(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setNaem(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() { // toString
return "Student [naem=" + name + ", age=" + age + "]";
}
}
package com.wsq.collection;
import java.util.ArrayList;
import java.util.Collection;
import com.wsq.bean.Student;
public class Demo3_Collection {
public static void main(String[] args) {
demo1();
demo2();
}
private static void demo2() { // , : ,
Collection c = new ArrayList();
c.add(new Student(" ",23)); //object obj = new student(" ",23);
c.add(new Student(" ",24)); // Studen
c.add(new Student(" ",25)); // Object
c.add(new Student(" ",26));
// c, c toString ,
Object [] arr = c.toArray(); // , Object , c.toArray() ; Object , Object
for (int i = 0; i < arr.length; i++) { //
//System.out.println(arr[i]); //
// arr , toString , ,
// Student , , Object , Object , Student getName getAge,
Student s = (Student)arr[i]; //
// Object [] arr = c.toArray(); c.toArray() Object ,new Student(" ",23), ,Student Object
// : ,Object getName getAge , Student ,
System.out.println(s.getName() + "..." + s.getAge());// getName getAge
//getName getAge , , , , , toString
}
}
public static void demo1(){ // , ,
Collection c = new ArrayList(); // c,
c.add("a"); //
c.add("b");
c.add("c");
c.add("d");
Object[] arr = c.toArray(); // , c.toArray() ; Object , Object
for(int i= 0;i// , , for
System.out.println(arr[i]); //
}
}
}