import java.util.HashMap;
/**
* @ClassName MyHashMap
* @Description TODO
* @Author lsy
* @Date 2019/2/15 9:01 PM
* Version 1.0
*/
public class MyHashMap<K, V> extends HashMap {
public static void main(String[] args) {
MyHashMap<Integer, Integer> myHashMap = new MyHashMap<Integer, Integer>();
for (int b = 7, c = 2; b <= 30 && c <= 30; b++, c += 2){
myHashMap.put(b, c);
//String str = JSON.toJSONString(maps);
}
System.out.println(myHashMap);
}
/**
*重写 toString 把=变成,
* @return
*/
@Override
public String toString() {
String s = super.toString();
s = s.replace("=", ",");
return s;
}
}
结果是
重写 父类的 toString 方法, 用 replace 方法, 替换;