常用Map循环遍历的方法
Map<String, Object> map = new HashMap<String, Object>();
map.put("1", "a");
map.put("2", "b");
map.put("3", "c");
System.out.println(map.containsKey("4"));
//构造测试数据
List<Map<String, Integer>> list = new ArrayList<>();
HashMap<String, Integer> map1 = new HashMap<String, Integer>() {
{
put("a", 16);
}
};
list.add(map1);
HashMap<String, Integer> map2 = new HashMap<String, Integer>() {
{
put("a", 17);
}
};
list.add(map2);
HashMap<String, Integer> map3 = new HashMap<String, Integer>() {
{
put("a", 18);
}
};
list.add(map3);
Iterator<Map<String, Integer>> iterator = list.iterator();
while (iterator.hasNext()) {
Map<String, Integer> info = iterator.next();
if (Integer.valueOf(info.get("a").toString()) > 16) {
iterator.remove();
}
}
for (Map<String, Integer> mapz : list) {
System.out.println(mapz.get("a"));
}
Map<String, Object> newmap = new HashMap<>();
newmap.put("1", "A");
newmap.put("2", "B");
newmap.put("3", "C");
//方法一
Set set = newmap.keySet();
Iterator iterator1 = set.iterator();
while (iterator1.hasNext()) {
Object next = iterator1.next();
System.out.println(next + "/" + newmap.get(next));
}
//方法二
Set<Map.Entry<String, Object>> setx = newmap.entrySet();
Iterator<Map.Entry<String, Object>> iteratorx = setx.iterator();
while (iteratorx.hasNext()) {
Map.Entry<String, Object> mapx = iteratorx.next();
System.out.println(mapx.getKey() + "/" + mapx.getValue());
}
//方法三
Set<Map.Entry<String, Object>> entries = newmap.entrySet();
for (Map.Entry<String, Object> entry : entries) {
System.out.println(entry.getKey() + ",value为：" + entry.getValue());
}
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