集合中保存对象，如何按对象中的属性排序？

package testProject;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class TestPro {

public static void main(String[] args) {

ArrayList<TestPro> zsList = new ArrayList<TestPro>();

zsList.add(new TestPro("1", "0000"));
zsList.add(new TestPro("Y", "1111"));
zsList.add(new TestPro("Y", "1111444"));
zsList.add(new TestPro("我是一个热好人", "2222"));
zsList.add(new TestPro("S", "3333"));
zsList.add(new TestPro("A", "4444"));
zsList.add(new TestPro("I", "5555"));
zsList.add(new TestPro("V", "6666"));
zsList.add(new TestPro("Q", "7777"));
zsList.add(new TestPro("I", "8888"));

Collections.sort(zsList, new Comparator<TestPro>() {

@Override
public int compare(TestPro o1, TestPro o2) {
// TODO Auto-generated method stub
return o1.getAbbreviation().compareTo(o2.getAbbreviation());
}

});

for (int i = 0; i < zsList.size(); i++) {
System.out.println(zsList.get(i).getAbbreviation() + "==="
+ zsList.get(i).getName());
}

}

private String abbreviation;
private String name;

public TestPro() {
super();
}

public TestPro(String abbreviation, String name) {
super();
this.abbreviation = abbreviation;
this.name = name;
}

public String getAbbreviation() {
return abbreviation;
}

public void setAbbreviation(String abbreviation) {
this.abbreviation = abbreviation;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}