1 Object[] key_arr = hashmap.keySet().toArray();   2 Arrays.sort(key_arr);   3 for  (Object key : key_arr) {   4     Object value =http://www.mamicode.com/ hashmap.get(key);   5 } 

  1 package Aug11.Collection;  2   3 import java.util.*;  4   5 public class EmployeeTest {  6     static int  EmId=237;  7     public static void main(String[] args) {  8         Scanner reader=new Scanner(System.in);  9         HashMap map = new HashMap(); 10         //TreeMap map = new TreeMap();  //sorted 11         Employee1 emp; 12         for (int i = 0; i <3; i++) { 13             emp=new Employee1(); 14             System.out.println("Enter name:"); 15             String name=reader.next(); 16             System.out.println("Enter address:"); 17             String addr=reader.next(); 18             System.out.println("Enter dateJoined(YY/mm/):"); 19             String dateJoined=reader.next(); 20             System.out.println("Enter dateBirth:"); 21             String dateBirth=reader.next(); 22             System.out.println("Enter basicPay:"); 23             double basicPay=reader.nextDouble(); 24              25             emp.setEmpName(name); 26             emp.setAddr(addr); 27             emp.setDateJoined(dateJoined); 28             emp.setBasicPay(basicPay);; 29             emp.setDateBirth(dateBirth);; 30             map.put(genEmpID(dateJoined), emp); 31              32         } 33      34         System.out.println("   EmpId     EmpName   Address  DateJoined  DateBirth  BasicPay"); 35           36         Object[] key_arr = map.keySet().toArray();      37         Arrays.sort(key_arr);      38         for  (Object key : key_arr) {      39              Employee1 em = (Employee1) map.get(key);     40             System.out.println(key+"\t"+em.getEmpName()+"\t"+em.getAddr()+"\t"+em.getDateJoined()+"\t"+em.getDateBirth()+"\t"+em.getBasicPay()); 41  42         }   43          44          /*Set<Integer> set = map.keySet(); 45           Iterator<Integer> iter = set.iterator(); 46          while(iter.hasNext()){ 47               int key = iter.next(); 48               Employee1 em=(Employee1) map.get(key); 49               System.out.println(key+"\t"+em.getEmpName()+"\t"+em.getAddr()+"\t"+em.getDateJoined()+"\t"+em.getDateBirth()+"\t"+em.getBasicPay()); 50          }*/ 51          52          } 53          54      55      56      57      58      59 public static int genEmpID(String dateJoined){ 60     String EmpID=dateJoined+(EmId+1); 61     EmId++; 62     String [] s=EmpID.split("/"); 63     StringBuffer bs=new StringBuffer(); 64     for(int i=0;i<s.length;i++){ 65         bs.append(s[i]); 66     } 67     int ID=Integer.parseInt(bs.toString()); 68     return ID; 69          70     } 71  72 } 73  74  75  76  77  78 class Employee1 { 79     private String empName; 80     private String addr; 81     private String dateJoined;  82     private String dateBirth; 83     private double basicPay; 84      85     public String getEmpName() { 86         return empName; 87     } 88     public void setEmpName(String empName) { 89         this.empName = empName; 90     } 91     public String getAddr() { 92         return addr; 93     } 94     public void setAddr(String addr) { 95         this.addr = addr; 96     } 97     public String getDateJoined() { 98         return dateJoined; 99     }100     public void setDateJoined(String dateJoined) {101         this.dateJoined = dateJoined;102     }103     public String getDateBirth() {104         return dateBirth;105     }106     public void setDateBirth(String dateBirth) {107         this.dateBirth = dateBirth;108     }109     public double getBasicPay() {110         return basicPay;111     }112     public void setBasicPay(double basicPay) {113         this.basicPay = basicPay;114     }115     116     117     118     119 }