将对象数组按字母顺序排序

Question

我在电话簿中有一系列条目。每个Entry对象都有三个字段。姓氏，姓名和姓名。我想按字母顺序按姓氏排序电话簿数组。我不确定最好的方法。我试图将compareTo方法用于字符串，但是如果一个姓氏是White而另一个姓氏是Smith，我不确定交换条目的最佳方法。我有一些代码，我认为只要不是第一个条目被添加到电话簿中，就可以将条目I添加到电话簿中，条目就在阵列之前。但它似乎根本没有对阵列产生任何影响。

 public class Entry implements Comparable<Entry>{

String surname;
String initial;
String number;


public Entry(String surname, String initial, String number) {
    this.surname = surname;
    this.initial = initial;
    this.number = number;
}

public String getSurname(){
    return surname;
}

public String getInitial(){
    return initial;
}

public String getNumber() {
    return number;
}

void setNumber(String number){
    this.number = number;
}

public String toString(){
    return surname+ "\t " +initial+ "\t" +number;
}


public int compareTo(Entry e) {
    return this.surname.compareToIgnoreCase(e.surname);
}


}


 import java.util.Arrays;

 public class ArrayDirectory implements Directory{


private int DIRECTORY_SIZE = 6; 
Entry [] directory = new Entry[DIRECTORY_SIZE];
private int numberOfElements = 0;

public int getNumOfElements(){
    return numberOfElements;
}

public void setDirectorySize(int size){
    DIRECTORY_SIZE = size;
}

public int getDirectorySize(){
    return DIRECTORY_SIZE;
}




public void addEntry(String surname, String initial, String num) {
    // TODO add an entry to an array, also increments numberOfElements variable tracking whats in array 

    if(getNumOfElements() == getDirectorySize()){    // if array is full
        doubleArraySize();     // put temp values into new bigger directory array
    }

    int i = findFreeLocation();     

    directory[i] = new Entry(surname, initial, num);

    if( i > 0 ){

        if(directory[i-1].compareTo(directory[i]) == 1){

            Entry[] temp = new Entry[1];
            temp[0] = directory[i-1];
            directory[i-1] = directory[i];
            directory[i] = temp[0];
        }

    }
    numberOfElements++;
}