数组求长度用length属性

字符串求长度用length()方法

集合求长度用size()方法

程序举例：

[java]
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1. package 集合.length_size;  
2.   
3. import java.util.ArrayList;  
4. import java.util.List;  
5.   
6. public class Length_Size {  
7.     public static void main(String[] args) {  
8.         String[] strings = {“aaa”,“bbb”,“ccc”};  
9.         String string = “aaabbbccc”;  
10.         List<Integer> list = new ArrayList<Integer>();  
11.         list.add(1);  
12.           
13.         System.out.println(“String[].length=”+strings.length);  
14.         System.out.println(“String.length()=”+string.length());  
15.         System.out.println(“List.size()=”+list.size());  
16.           
17.     }  
18.   
19. }  

package 集合.length_size;

import java.util.ArrayList;
import java.util.List;

public class Length_Size {
	public static void main(String[] args) {
		String[] strings = {"aaa","bbb","ccc"};
		String string = "aaabbbccc";
		List<Integer> list = new ArrayList<Integer>();
		list.add(1);
		
		System.out.println("String[].length="+strings.length);
		System.out.println("String.length()="+string.length());
		System.out.println("List.size()="+list.size());
		
	}

}