public class DateUtilTest {
public void testDeleteElement(List<String> list) throws Exception{
for (int i=list.size()-1;i>=0;i--) {
if(list.get(i).equals("5")){
list.remove(i);
continue;
}
if(i%1000 == 0){
Thread.sleep(100);
System.out.println("Current Thread is " + Thread.currentThread().getName());
}
}
System.out.println(list.toString());
}
public void testDeleteElementWithIterator(List<String> list) throws Exception{
Iterator<String> iterator = list.iterator();
int i=0;
while(iterator.hasNext()){
if(iterator.next().equals("5")){
iterator.remove();
}
if(i%1000 == 0){
Thread.sleep(100);
System.out.println("Current Thread is " + Thread.currentThread().getName());
}
i++;
}
System.out.println(list.toString());
}
public static void main(String[] args) throws Exception{
DateUtilTest test = new DateUtilTest();
List<String> list = test.init();
Thread t1 = new Thread(
new Runnable() {
@Override
public void run() {
try{
test.testDeleteElementWithIterator(list);
System.out.println("Thread1 is running");
}catch(Throwable t){
t.printStackTrace();
}
}
}, "thread-1"
);
Thread t2 = new Thread(
new Runnable() {
@Override
public void run() {
try{
test.testDeleteElementWithIterator(list);
System.out.println("Thread2 is running");
}catch(Throwable t){
t.printStackTrace();
}
}
}, "thread-2"
);
t1.start();
t2.start();
}
public List<String> init(){
List<String> list = new ArrayList<>();
list.add("1");
list.add("2");
list.add("3");
list.add("4");
list.add("5");
list.add("5");
list.add("6");
list.add("7");
list.add("8");
list.add("9");
for(int i=10; i< 100000; i++){
list.add(i + "");
}
return list;
}
}
用iterator会报ConcurrentModificationException异常在并发的时候，用index不会。
