#
package cn.sxt.myCollection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
public class SxtHashSet {
HashMap map;
private static final Object PRESENT = new Object();
public SxtHashSet(){
map = new HashMap();
}
public int size(){
return map.size();
}
public void add(Object o){
map.put(o, PRESENT);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("[");
for (Object key : map.keySet()) {
sb.append(key + ",");
}
sb.setCharAt(sb.length() - 1, ']');;
return sb.toString();
}
public static void main(String[] args) {
Set<String> set1 = new HashSet<String>();
set1.add("sober");
set1.add("nora");
set1.add("sober");
System.out.println(set1);
set1.remove("sober");
System.out.println(set1);
}
}
运行结果：
[nora, sober]
[nora]
注意：重写toString方法多关注关注
