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遍历数组
String[] arr = { "包青天", "白乾涛", "baiqiantao", "bqt", "0909082401", };for (int i = 0; i < arr.length; i++) {//普通forSystem.out.println("第" + (i + 1) + "个元素为：" + arr[i]);}for (String i : arr) {//增强forSystem.out.println("元素为：" + i);}
遍历List、Set
List<String> mList = new ArrayList<String>();mList.add("包青天a");mList.add("包青天c");mList.add("包青天b");System.out.println(mList); //[包青天a, 包青天c, 包青天b]for (String string : mList) {//增强forSystem.out.println("---" + string);}Iterator<String> it = mList.iterator();while (it.hasNext()) {//迭代器System.out.println(it.next());}//list特有的ListIterator，可以双向遍历ListIterator<String> it2 = mList.listIterator();while (it2.hasNext()) {//List迭代器System.out.println("*******" + it2.next());//执行完后指针移到了最后，这有这样才能使用hasPrevious遍历}while (it2.hasPrevious()) {//List迭代器System.out.println(it2.previous() + "*****");}
遍历Map
Map<Integer, String> map = new HashMap<Integer, String>();map.put(30, "zhagsan");map.put(17, "李四");map.put(2016, "包青天");System.out.println(map);//{17=李四, 2016=包青天, 30=zhagsan}for (Integer key : map.keySet()) {//增强for遍历keyString value = map.get(key);System.out.println(key + "---" + value);}for (Map.Entry<Integer, String> k_v : map.entrySet()) {//增强for遍历键值对System.out.println(k_v);//17=李四}Iterator<Integer> iterator = map.keySet().iterator();while (iterator.hasNext()) {//健的Set集合的迭代器Integer key = iterator.next();String value = map.get(key);System.out.println(key + ":" + value);}Iterator<Map.Entry<Integer, String>> iterator2 = map.entrySet().iterator();while (iterator2.hasNext()) {//键值对的迭代器System.out.println(iterator2.next());//17=李四}
List嵌套Map
ArrayList<HashMap<String, String>> array = new ArrayList<HashMap<String, String>>();HashMap<String, String> hm1 = new HashMap<String, String>();hm1.put("周瑜", "小乔");hm1.put("吕布", "貂蝉");// 把元素添加到array里面array.add(hm1);HashMap<String, String> hm2 = new HashMap<String, String>();hm2.put("郭靖", "黄蓉");hm2.put("杨过", "小龙女");// 把元素添加到array里面array.add(hm2);// 遍历for (HashMap<String, String> hm : array) {Set<String> set = hm.keySet();for (String key : set) {String value = hm.get(key);System.out.println(key + "-" + value);}System.out.println("//**************************");}}
Map嵌套Map
HashMap<String, HashMap<String, Integer>> mMap = new HashMap<String, HashMap<String, Integer>>();HashMap<String, Integer> jcMap = new HashMap<String, Integer>();jcMap.put("陈玉楼", 20);jcMap.put("高跃", 22);mMap.put("基础班", jcMap);HashMap<String, Integer> jyMap = new HashMap<String, Integer>();jyMap.put("李杰", 21);jyMap.put("曹石磊", 23);mMap.put("就业班", jyMap);//遍历集合Set<String> mKeySet = mMap.keySet();for (String mKey : mKeySet) {System.out.println(mKey);HashMap<String, Integer> mValue = mMap.get(mKey);Set<String> mValueKeySet = mValue.keySet();for (String mValueKey : mValueKeySet) {Integer mValueValue = mValue.get(mValueKey);System.out.println("\t" + mValueKey + "-" + mValueValue);}}
Map嵌套List
HashMap<String, ArrayList<String>> hashMap = new HashMap<String, ArrayList<String>>();ArrayList<String> array1 = new ArrayList<String>();array1.add("吕布");array1.add("周瑜");array1.add("包青天");hashMap.put("三国演义人物", array1);ArrayList<String> array2 = new ArrayList<String>();array2.add("令狐冲");array2.add("林平之");array2.add("包青天");hashMap.put("笑傲江湖人物", array2);//遍历集合Set<String> keySet = hashMap.keySet();for (String key : keySet) {System.out.println(key);ArrayList<String> valueList = hashMap.get(key);for (String string : valueList) {System.out.println("\t" + string);}}
多层嵌套
HashMap<String, HashMap<String, ArrayList<Student>>> mMap = new HashMap<String, HashMap<String, ArrayList<Student>>>();// 北京校区数据HashMap<String, ArrayList<Student>> bjmMap = new HashMap<String, ArrayList<Student>>();ArrayList<Student> array1 = new ArrayList<Student>();Student s1 = new Student("林青霞", 27);Student s2 = new Student("风清扬", 30);array1.add(s1);array1.add(s2);ArrayList<Student> array2 = new ArrayList<Student>();Student s3 = new Student("赵雅芝", 28);Student s4 = new Student("武鑫", 29);array2.add(s3);array2.add(s4);bjmMap.put("基础班", array1);bjmMap.put("就业班", array2);mMap.put("北京校区", bjmMap);// 广州校区数据HashMap<String, ArrayList<Student>> xamMap = new HashMap<String, ArrayList<Student>>();ArrayList<Student> array3 = new ArrayList<Student>();Student s5 = new Student("范冰冰", 27);Student s6 = new Student("刘意", 30);array3.add(s5);array3.add(s6);ArrayList<Student> array4 = new ArrayList<Student>();Student s7 = new Student("李冰冰", 28);Student s8 = new Student("张志豪", 29);array4.add(s7);array4.add(s8);xamMap.put("基础班", array3);xamMap.put("就业班", array4);mMap.put("广州校区", xamMap);// 遍历集合Set<String> mMapSet = mMap.keySet();for (String mMapKey : mMapSet) {System.out.println(mMapKey);HashMap<String, ArrayList<Student>> mMapValue = mMap.get(mMapKey);Set<String> mMapValueSet = mMapValue.keySet();for (String mMapValueKey : mMapValueSet) {System.out.println("\t" + mMapValueKey);ArrayList<Student> mMapValueValue = mMapValue.get(mMapValueKey);for (Student s : mMapValueValue) {System.out.println("\t\t" + s.getName() + "-" + s.getAge());}}}
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原文地址：http://www.cnblogs.com/baiqiantao/p/5449039.html
