晕怎么可能没导入包 package com.contains;import java.util.*;public class Map {
public static void main(String[] args) { Map m1 = new HashMap(); Map m2 = new HashMap(); m1.put("one", new Integer(1)); m1.put("two", new Integer(2)); m1.put("three",new Integer(3)); m2.put("A", new Integer(1)); m2.put("B", new Integer(2));
if(m1.containsKey("two")) { int i = ((Integer)m1.get("two")).intValue(); System.out.println(i); }
Map m3 = new HashMap(m1); m3.putAll(m2); System.out.println(m3); }}
你自己的那个类名就是Map编译器当然认为程序里面声明的那个Map是你的类
package com.contains;import java.util.*;public class Map { public static void main(String[] args) { java.util.Map m1 = new HashMap(); java.util.Map m2 = new HashMap(); m1.put("one", new Integer(1)); m1.put("two", new Integer(2)); m1.put("three", new Integer(3)); m2.put("A", new Integer(1)); m2.put("B", new Integer(2)); System.out.println(m1.size()); System.out.println(m1.containsKey("one")); System.out.println(m2.containsValue(new Integer(2))); if (m1.containsKey("two")) { int i = ((Integer) m1.get("two")).intValue(); System.out.println(i); } java.util.Map m3 = new HashMap(m1); m3.putAll(m2); System.out.println(m3); }}
package com.contains;import java.util.*;public class Map {
public static void main(String[] args) {
Map m1 = new HashMap();
Map m2 = new HashMap();
m1.put("one", new Integer(1));
m1.put("two", new Integer(2));
m1.put("three",new Integer(3));
m2.put("A", new Integer(1));
m2.put("B", new Integer(2));
System.out.println(m1.size());
System.out.println(m1.containsKey("one"));
System.out.println(m2.containsValue(new Integer(2)));
if(m1.containsKey("two")) {
int i = ((Integer)m1.get("two")).intValue();
System.out.println(i);
}
Map m3 = new HashMap(m1);
m3.putAll(m2);
System.out.println(m3);
}}
java.util.Map m1 = new HashMap();
java.util.Map m2 = new HashMap();
m1.put("one", new Integer(1));
m1.put("two", new Integer(2));
m1.put("three", new Integer(3));
m2.put("A", new Integer(1));
m2.put("B", new Integer(2)); System.out.println(m1.size());
System.out.println(m1.containsKey("one"));
System.out.println(m2.containsValue(new Integer(2))); if (m1.containsKey("two")) {
int i = ((Integer) m1.get("two")).intValue();
System.out.println(i);
} java.util.Map m3 = new HashMap(m1);
m3.putAll(m2);
System.out.println(m3);
}}