ListTest.java
package com.klvchen.java;
import org.junit.Test;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
public class ListTest {
@Test
public void test3(){
ArrayList list = new ArrayList();
list.add(123);
list.add(456);
list.add("AA");
//方式一: Iterator迭代器方式
Iterator iterator = list.iterator();
while (iterator.hasNext()){
System.out.println(iterator.next());
}
System.out.println("********************");
//方式二:
for(Object obj: list){
System.out.println(obj);
}
System.out.println("********************");
//方式三
for (int i = 0; i < list.size(); i++){
System.out.println(list.get(i));
}
}
@Test
public void test2(){
ArrayList list = new ArrayList();
list.add(123);
list.add(456);
list.add("AA");
list.add(new Person("Tom", 12));
list.add(456);
//int indexOf(Object obj):返回obj在集合中首次出现的位置。如果不存在,返回-1
int index = list.indexOf(456);
System.out.println(index);
//int lasterIndexOf(Object obj):返回obj在当前集合中末次出现的位置
System.out.println(list.lastIndexOf(456));
//Object remove(int index):移除指定位置的元素,并返回此元素
Object obj = list.remove(0);
System.out.println(obj);
System.out.println(list);
//Object set(int index, Object ele):设置指定index位置的元素为ele
list.set(1, "CC");
System.out.println(list);
//List subList(int fromIndex, int toIndex):返回从fromIndex到toIndex位置的左闭右开集合
List subList = list.subList(2, 4);
System.out.println(subList);
System.out.println(list);
}
@Test
public void test1(){
ArrayList list = new ArrayList();
list.add(123);
list.add(456);
list.add("AA");
list.add(new Person("Tom", 12));
list.add(456);
System.out.println(list);
//void add(int index, Object ele): 在index位置插入ele元素
list.add(1, "BB");
System.out.println(list);
//boolean addAll(int index, Collection eles): 从index位置开始将eles中的所有元素
List list1 = Arrays.asList(1, 2, 3);
//list.add(list1);
list.addAll(list1);
System.out.println(list.size());
//Object get(int index): 获取指定index位置的元素
System.out.println(list.get(0));
}
}
ListExer.java
package com.klvchen.exer;
import org.junit.Test;
import java.util.ArrayList;
import java.util.List;
public class ListExer {
@Test
public void testListRemove(){
List list = new ArrayList();
list.add(1);
list.add(2);
list.add(3);
updateList(list);
System.out.println(list);
}
private void updateList(List list){
//list.remove(2);
list.remove(new Integer(2));
}
}