问使用Java对某个范围内的用户按年龄分组

EN

Age Group                 Age Range
1                         6 years old or younger
2                         7 to 18 years old
3                         19 to 26 years old
4                         27 to 49 years old
5                         50 to 64 years old
6                         65 to 79 years old
7                         80 years old or older

If I enter 1

**** users found (total number of users that falls within the 
age range 6 years old or younger)

 /**
 A template used to read data lines into java.util.ArrayList data structure.
 Input file: pjData.csv
 Input file must be saved under the same directory/folder as the program.
 Each line contains 5 fields, separated by commas. For example,
 959695171, 64, AZ, M, 1
 355480298, 101, TN, F, 1
 **/
 import java.io.*;
 import java.util.*;
 public class pj3Template2
 {
  public static void main(String args[]) 
 {
String line;
String id, s, g;
Integer a, sa;
StringTokenizer st;
HealthDS2 records = new HealthDS2(); 
try   {
      FileReader f = new FileReader("pjData.csv");
      BufferedReader in = new BufferedReader(f);
      while ((line = in.readLine()) != null)
         {
         st = new StringTokenizer(line, ",");
         id = st.nextToken(",").trim();
         a = Integer.valueOf(st.nextToken(",").trim());
         s = st.nextToken(",").trim().toUpperCase();
         g = st.nextToken(",").trim().toUpperCase();
         sa = Integer.valueOf(st.nextToken().trim());
         records.add(new HealthRec2(id, a, s, g, sa));
         } // loop until the end of file
      in.close(); 
      f.close();
      }
      catch (Exception e) {  e.printStackTrace(); };
System.out.println(records.getSize() + " records processed.");

 // Search by age
System.out.print("Enter 1-character age abbreviation to search: ");
String ui;
Scanner input = new Scanner(System.in);
ui = input.next().trim();
System.out.println("Searching all records in: " + ui);

ArrayList <HealthRec2> al = records.searchByAge(Integer.valueOf(ui.trim()));
System.out.println(al.size() + " records found.");    

     }
 }

 /**
 Data class Sample records:
 5501986, 31, WV, F, 1
 1539057187, 5, UT, M, 2
 **/
 class HealthRec2
 {
    String ID;
    Integer age;
    String state;
    String gender;
    int status;
    public HealthRec2() { }
    public HealthRec2(String i, Integer a, String s, String g, int sa)
       { ID = i; age = a;  state = s; gender = g; status = sa; }
 // Reader methods
 public String getID()     { return ID; }
 public Integer getAge()   { return age; }
 public String getState()  { return state; }
 public String getGender() { return gender; }
 public int getStatus()    { return status; }
 // Writer methods
 public void setAge(Integer a)   { age = a; }
 public void setState(String s)  { state = s; }
 public void setGender(String g) { gender = g; }
 public void setStatus(int sa)   { status = sa; }

 public String toString()
 { return ID + "  " + age + "  " + state + "   " + gender + "  " + status; }
 } // HealthRec


 // Data structure used to implement the requirement
 // This implementation uses java.util.ArrayList
 class HealthDS2
 {
 ArrayList <HealthRec2> rec;
 public HealthDS2() 
  { rec = new ArrayList <HealthRec2>(); }
 public HealthDS2(HealthRec2 r) 
 { 
 rec = new ArrayList <HealthRec2>();
 rec.add(r); 
 }
 public int getSize() { return rec.size(); }
 public void add(HealthRec2 r) { rec.add(r); }

// Search by age
// No data validation is needed -- assuming the 1-character age is valid
// Returns an ArrayList of records
public ArrayList <HealthRec2> searchByAge(Integer a)
{
ArrayList <HealthRec2> temp = new ArrayList <HealthRec2>();
  for (int k=0; k < rec.size(); ++k)
  {
  if (rec.get(k).getAge().equals(a))
     temp.add(rec.get(k));  
  }
  return temp;
  } // searchByAge
  } // HealthDS