java例程练习（泛型和自动打包、解包）

//TestArsgWords.java
import java.util.*;
public class TestArgsWords {

public static void main(String[] args) {
Map m = new HashMap();

for(int i = 0; i < args.length; i++) {

if(!m.containsKey(args[i])) {
m.put(args[i], 1);
} else {
int freq = m.get(args[i]);
m.put(args[i], freq + 1);
}

}

System.out.println
(m.size() + " distinct words detected:");
System.out.println(m);
}
}
[java]

//Test.java 
 import java.util.*; 
  
 public class Test { 
     public static void main(String[] args) { 
         List c = new ArrayList(); 
          
         c.add("aaa"); 
         c.add("bbb"); 
         c.add("ccc"); 
          
         for(int i = 0; i < c.size(); i++) { 
             String s = c.get(i); 
             System.out.println(s); 
         } 
          
         Collection c2 = new HashSet (); 
         c2.add("aaa"); 
         c2.add("bbb"); 
         c2.add("ccc"); 
          
         for(Iterator it = c2.iterator(); it.hasNext();) { 
             String s = it.next(); 
             System.out.println(s); 
         } 
          
     } 
 } 
  
  
 class MyName implements Comparable { 
     int age; 
      
     public int compareTo(MyName mn) { 
         if(this.age > mn.age) { 
             return 1; 
         } else if(this.age < mn.age) { 
             return -1; 
         } else { 
             return 0; 
         } 
     } 
 } 
 
 

 [java]
 
//Test.java 
 import java.util.*; 
  
 public class Test { 
     public static void main(String[] args) { 
         Map m1 = new HashMap(); 
         Map m2 = new HashMap(); 
          
         m1.put("one", 1); 
         //m1.put("one",new Integer(1)); 
          
         m1.put("two", 2); 
         //m1.put("two",new Integer(2)); 
          
         m1.put("three", 3); 
         //m1.put("three",new Integer(3)); 
          
         m2.put("A", 1); 
         //m2.put("A", new Integer(1)); 
          
         m2.put("B", 2); 
         //m2.put("B", new Integer(2)); 
          
         System.out.println(m1.size()); 
         System.out.println(m1.containsKey("one")); 
         System.out.println 
             (m2.containsValue(1)); 
             //(m2.containsValue(new Integer(1))); 
         if(m1.containsKey("two")) { 
             int i = m1.get("two"); 
             //int i =(Integer)m1.get("two"); 
             //int i = ((Integer)m1.get("two")).intValue(); 
             System.out.println(i); 
         } 
          
         Map m3 = new HashMap(m1); 
         m3.putAll(m2); 
         System.out.println(m3); 
     } 
 } 
 
 
 





 
 

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