java 遍历Map及Map转化为二维数组的实例

java 遍历map及map转化为二维数组的实例

实例代码：

import java.util.hashmap; 
import java.util.iterator; 
import java.util.map; 
 
public class test { 
  public static void main(string[] args) { 
    int a = 0, b = 0, c = 0; 
    // 第一种:通过map.keyset()遍历map及将map转化为二维数组 
    map<string, string> map1 = new hashmap<string, string>(); 
    map1.put("012013012013", "张三"); 
    map1.put("012013012014", "张四"); 
    string[][] group1 = new string[map1.size()][2]; 
    system.out.println("第一种:通过map.keyset()遍历map1的key和value"); 
    for (string key : map1.keyset()) {  
      system.out.println("key = " + key + " and value = " + map1.get(key));  
      group1[a][0] = key; 
      group1[a][1] = map1.get(key); 
      a++; 
    }  
    system.out.println("map1.size()为：" + map1.size() + ",a为：" + a + "，group1数组的长度为：" + group1.length); 
    system.out.println("----------------------------------------------------"); 
    for(int n = 0; n < group1.length; n++) { 
      system.out.println("key = " + group1[n][0] + " and value = " + group1[n][1]);  
    } 
     
    // 第二种:通过map.entryset()使用iterator()遍历map及将map转化为二维数组 
    map<string, string> map2 = new hashmap<string, string>(); 
    map2.put("112013012013", "李三"); 
    map2.put("112013012014", "李四"); 
    system.out.println("\n" + "第二种:通过map.entryset()使用iterator()遍历map2的key和value"); 
    iterator<map.entry<string, string>> iterator = map2.entryset().iterator();  
    string[][] group2 = new string[map2.size()][2]; 
    while (iterator.hasnext()) {  
      map.entry<string, string> entry = iterator.next();         
      system.out.println("key = " + entry.getkey() + " and value = " + entry.getvalue()); 
      group2[b][0] = entry.getkey(); 
      group2[b][1] = entry.getvalue(); 
      b++; 
    }  
    system.out.println("map2.size()为：" + map2.size() + ",b为：" + b + "，group2数组的长度为：" + group2.length); 
    system.out.println("----------------------------------------------------"); 
    for(int n = 0; n < group2.length; n++) { 
      system.out.println("key = " + group2[n][0] + " and value = " + group2[n][1]);  
    } 
     
    // 第三种:通过map.entryset()遍历遍历map及将map转化为二维数组 
    map<string, string> map = new hashmap<string, string>(); 
    map.putall(map1); 
    map.putall(map2);   
    string[][] group3 = new string[map.size()][2]; 
    system.out.println("\n" + "第三种:通过map.entryset()遍历map的key和value ");    
    for (map.entry<string, string> entry : map.entryset()) {  
      system.out.println("key = " + entry.getkey() + " and value = " + entry.getvalue());  
      group3[c][0] = entry.getkey(); 
      group3[c][1] = entry.getvalue(); 
      c++; 
    } 
    system.out.println("map.size()为：" + map.size() + ",c为：" + c + "，group3数组的长度为：" + group3.length); 
    system.out.println("----------------------------------------------------"); 
    for(int n = 0; n < group3.length; n++) { 
      system.out.println("key = " + group3[n][0] + " and value = " + group3[n][1]);  
    } 
     
  } 
} 

输出结果为：

第一种:通过map.keyset()遍历map1的key和value 
key = 012013012013 and value = 张三 
key = 012013012014 and value = 张四 
map1.size()为：2,a为：2，group1数组的长度为：2 
---------------------------------------------------- 
key = 012013012013 and value = 张三 
key = 012013012014 and value = 张四 
 
第二种:通过map.entryset()使用iterator()遍历map2的key和value 
key = 112013012014 and value = 李四 
key = 112013012013 and value = 李三 
map2.size()为：2,b为：2，group2数组的长度为：2 
---------------------------------------------------- 
key = 112013012014 and value = 李四 
key = 112013012013 and value = 李三 
 
第三种:通过map.entryset()遍历map的key和value  
key = 112013012014 and value = 李四 
key = 112013012013 and value = 李三 
key = 012013012013 and value = 张三 
key = 012013012014 and value = 张四 
map.size()为：4,c为：4，group3数组的长度为：4 
---------------------------------------------------- 
key = 112013012014 and value = 李四 
key = 112013012013 and value = 李三 
key = 012013012013 and value = 张三 
key = 012013012014 and value = 张四 

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