怎样从java集合类set中取出数据？ java中怎么往集合类set里添加数据？？
\u600e\u6837\u4ecejava\u96c6\u5408\u7c7bset\u4e2d\u53d6\u51fa\u6570\u636e\u4e00\u822c\u662f\u901a\u8fc7\u8fed\u4ee3\u671f\u83b7\u53d6\u6570\u636e\uff0c\u56e0\u4e3aset\u96c6\u5408\u65e0\u5e8f\uff0c\u6240\u4ee5\u8f93\u51fa\u4e0d\u662f\u987a\u5e8f\u8f93\u51fa
import java.util.HashSet;import java.util.Iterator;import java.util.Set;public class Test{ public static void main(String[] args) { // \u521d\u59cb\u5316set\u96c6\u5408 Set set = new HashSet(); set.add("1"); set.add("2"); set.add("3"); // \u83b7\u53d6set\u96c6\u5408\u6570\u636e for (Iterator iterator = set.iterator(); iterator.hasNext();) { String string = (String) iterator.next(); System.out.println(string); } }}
\u89c6\u9891\u8bb2\u89e3\u7684\u662fJava\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b\u8bed\u8a00\u4e2d\u7684\u96c6\u5408\u6846\u67b6HashSet\u6dfb\u52a0\u81ea\u5b9a\u4e49\u5bf9\u8c61\u65f6\u5019\u7684\u5de5\u4f5c\u539f\u7406\u3002\u9996\u5148\u4f1a\u8c03\u7528hashCode\u65b9\u6cd5\uff0c\u5224\u65ad\u8be5\u5bf9\u8c61\u662f\u5426\u548c\u96c6\u5408\u4e2d\u7684\u5bf9\u8c61\u7684hashCode\u4e00\u81f4\uff0c\u5982\u679c\u4e00\u81f4\u5219\u4e0d\u6dfb\u52a0\u3002
用循环或者迭代器
创建set的iterator
Set<Object> set = new HashSet<Object>();
Iterator<Object> it = set.iterator();
while(it.hasNext())//判断是否有下一个
it.next()取出元素
======================================
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
class ADD{
public String a;
public static void main(String[] args) {
ADD a = new ADD();
a.a = "a";
ADD b = new ADD();
b.a = "b";
Set<ADD> set = new HashSet<ADD>();
set.add(a);
set.add(b);
Iterator<ADD> it = set.iterator();
while(it.hasNext()){
System.out.println(((ADD)it.next()).a);
}
}
}
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