Java 遍历方法总结

 package com.zlh;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;

 public class TravelseDemo {

     public static void main(String[] args) {
         // 数组遍历
         System.out.println("1 数组遍历");
         String[] str1 = { "数", "组", "遍", "历" };
         arrayTravelse(str1);
         System.out.println("===================");
         // 字符串遍历
         System.out.println("2 字符串遍历");
         String str2 = "字符串遍历";
         stringTravelse(str2);
         System.out.println("===================");
         // list遍历
         ArrayList<String> list = new ArrayList<String>();
         list.add("集");
         list.add("合");
         list.add("遍");
         list.add("历");
         // list遍历-for-each
         System.out.println("3 list遍历-for-each");
         forTravelse(list);
         System.out.println("===================");
         // list遍历-迭代器
         System.out.println("4 list遍历-迭代器");
         iteratorTravelse(list);
         System.out.println("===================");
         // map遍历
         Map<String, Integer> map = new HashMap<String, Integer>();
         map.put("jack", 1);
         map.put("tom", 2);
         map.put("jerry", 3);
         // map遍历-for-each与keySet
         System.out.println("5 map遍历-for-each与keySet");
         forKeySetTravelse(map);
         System.out.println("===================");
         // map遍历-迭代器与keySet
         System.out.println("6 map遍历-迭代器与keySet");
         iteratorKeySetTravelse(map);
         System.out.println("===================");
         // map遍历-for-each与entry
         System.out.println("7 map遍历-for-each与entry");
         forEntryTravelse(map);
         System.out.println("===================");
         // map遍历-迭代器与entry
         System.out.println("8 map遍历-迭代器与entry");
         iteratorEntryTravelse(map);
     }

     // 数组遍历
     private static void arrayTravelse(String[] str) {
         for (int i = 0; i < str.length; i++) {
             String j = str[i];
             System.out.print(j + " ");
         }
         System.out.println();
     }

     // 字符串遍历
     private static void stringTravelse(String str) {
         for (int i = 0; i < str.length(); i++) {
             char c = str.charAt(i);
             System.out.print(c + " ");
         }
         System.out.println();
     }

     // for-each循环遍历
     private static void forTravelse(ArrayList<String> list) {
         for (String str : list) {
             System.out.print(str + " ");
         }
         System.out.println();
     }

     // 迭代器遍历
     private static void iteratorTravelse(ArrayList<String> list) {
         Iterator<String> it = list.iterator();
         while (it.hasNext()) {
             String next = it.next();
             System.out.print(next + " ");
         }
         System.out.println();
     }

     // map遍历-for-each与keySet
     private static void forKeySetTravelse(Map<String, Integer> map) {
         Set<String> set = map.keySet();
         for (String key : set) {
             Integer value = map.get(key);
             System.out.print(key + ":" + value + " ");
         }
         System.out.println();
     }

     // map遍历-迭代器与keySet
     private static void iteratorKeySetTravelse(Map<String, Integer> map) {
         Set<String> set = map.keySet();
         Iterator<String> it = set.iterator();
         while(it.hasNext()) {
             String key = it.next();
             Integer value = map.get(key);
             System.out.print(key + ":" + value + " ");
         }
         System.out.println();
     }

     // map遍历-for-each与entry
     private static void forEntryTravelse(Map<String, Integer> map) {
         Set<Entry<String, Integer>> set = map.entrySet();
         for (Map.Entry<String, Integer> entry : set) {
             String key = entry.getKey();
             Integer value = entry.getValue();
             System.out.print(key + ":" + value + " ");
         }
         System.out.println();
     }

     // map遍历-迭代器与entry
     private static void iteratorEntryTravelse(Map<String, Integer> map) {
         Set<Entry<String, Integer>> set = map.entrySet();
         Iterator<Entry<String, Integer>> it = set.iterator();
         while (it.hasNext()) {
             Entry<String, Integer> en = it.next();
             String key = en.getKey();
             Integer value = en.getValue();
             System.out.print(key + ":" + value + " ");
         }
         System.out.println();
     }
 }