Java 遍历方法总结

2019-02-20 00:45:32来源：博客园阅读 ()

  1 package com.zlh;
  2 
  3 import java.util.ArrayList;
  4 import java.util.HashMap;
  5 import java.util.Iterator;
  6 import java.util.Map;
  7 import java.util.Map.Entry;
  8 import java.util.Set;
  9 
 10 public class TravelseDemo {
 11 
 12     public static void main(String[] args) {
 13         // 数组遍历
 14         System.out.println("1 数组遍历");
 15         String[] str1 = { "数", "组", "遍", "历" };
 16         arrayTravelse(str1);
 17         System.out.println("===================");
 18         // 字符串遍历
 19         System.out.println("2 字符串遍历");
 20         String str2 = "字符串遍历";
 21         stringTravelse(str2);
 22         System.out.println("===================");
 23         // list遍历
 24         ArrayList<String> list = new ArrayList<String>();
 25         list.add("集");
 26         list.add("合");
 27         list.add("遍");
 28         list.add("历");
 29         // list遍历-for-each
 30         System.out.println("3 list遍历-for-each");
 31         forTravelse(list);
 32         System.out.println("===================");
 33         // list遍历-迭代器
 34         System.out.println("4 list遍历-迭代器");
 35         iteratorTravelse(list);
 36         System.out.println("===================");
 37         // map遍历
 38         Map<String, Integer> map = new HashMap<String, Integer>();
 39         map.put("jack", 1);
 40         map.put("tom", 2);
 41         map.put("jerry", 3);
 42         // map遍历-for-each与keySet
 43         System.out.println("5 map遍历-for-each与keySet");
 44         forKeySetTravelse(map);
 45         System.out.println("===================");
 46         // map遍历-迭代器与keySet
 47         System.out.println("6 map遍历-迭代器与keySet");
 48         iteratorKeySetTravelse(map);
 49         System.out.println("===================");
 50         // map遍历-for-each与entry
 51         System.out.println("7 map遍历-for-each与entry");
 52         forEntryTravelse(map);
 53         System.out.println("===================");
 54         // map遍历-迭代器与entry
 55         System.out.println("8 map遍历-迭代器与entry");
 56         iteratorEntryTravelse(map);
 57     }
 58 
 59     // 数组遍历
 60     private static void arrayTravelse(String[] str) {
 61         for (int i = 0; i < str.length; i++) {
 62             String j = str[i];
 63             System.out.print(j + " ");
 64         }
 65         System.out.println();
 66     }
 67 
 68     // 字符串遍历
 69     private static void stringTravelse(String str) {
 70         for (int i = 0; i < str.length(); i++) {
 71             char c = str.charAt(i);
 72             System.out.print(c + " ");
 73         }
 74         System.out.println();
 75     }
 76 
 77     // for-each循环遍历
 78     private static void forTravelse(ArrayList<String> list) {
 79         for (String str : list) {
 80             System.out.print(str + " ");
 81         }
 82         System.out.println();
 83     }
 84 
 85     // 迭代器遍历
 86     private static void iteratorTravelse(ArrayList<String> list) {
 87         Iterator<String> it = list.iterator();
 88         while (it.hasNext()) {
 89             String next = it.next();
 90             System.out.print(next + " ");
 91         }
 92         System.out.println();
 93     }
 94 
 95     // map遍历-for-each与keySet
 96     private static void forKeySetTravelse(Map<String, Integer> map) {
 97         Set<String> set = map.keySet();
 98         for (String key : set) {
 99             Integer value = map.get(key);
100             System.out.print(key + ":" + value + " ");
101         }
102         System.out.println();
103     }
104 
105     // map遍历-迭代器与keySet
106     private static void iteratorKeySetTravelse(Map<String, Integer> map) {
107         Set<String> set = map.keySet();
108         Iterator<String> it = set.iterator();
109         while(it.hasNext()) {
110             String key = it.next();
111             Integer value = map.get(key);
112             System.out.print(key + ":" + value + " ");
113         }
114         System.out.println();
115     }
116     
117     // map遍历-for-each与entry
118     private static void forEntryTravelse(Map<String, Integer> map) {
119         Set<Entry<String, Integer>> set = map.entrySet();
120         for (Map.Entry<String, Integer> entry : set) {
121             String key = entry.getKey();
122             Integer value = entry.getValue();
123             System.out.print(key + ":" + value + " ");
124         }
125         System.out.println();
126     }
127 
128     // map遍历-迭代器与entry
129     private static void iteratorEntryTravelse(Map<String, Integer> map) {
130         Set<Entry<String, Integer>> set = map.entrySet();
131         Iterator<Entry<String, Integer>> it = set.iterator();
132         while (it.hasNext()) {
133             Entry<String, Integer> en = it.next();
134             String key = en.getKey();
135             Integer value = en.getValue();
136             System.out.print(key + ":" + value + " ");
137         }
138         System.out.println();
139     }
140 }