import java.util.ArrayList;
import java.util.List;
import java.util.Collection;
public class ArrayListDemo03 {
public static void main(String args[]){
List<String> allList=null;
allList =new ArrayList<String>();
allList.add("Hello");
allList.add("World");
allList.add(0,"YuuW24k");
Collection<String> allCollection=null;
allCollection =new ArrayList<String>();
allCollection.add("Sad");
allCollection.add("or");
allCollection.add("Happy");
allList.addAll(1, allCollection);
System.out.println(allList);
System.out.print("由前向后输出:");
for(int i=0;i<=allList.size();i++){
System.out.print(allList.get(i)+",");
}
System.out.print("\n由后向前输出:");
for(int i=allList.size();i<=0;i--){
System.out.print(allList.get(i)+",");
}
}
}
for(int i=0;i<allList.size();i++){
System.out.print(allList.get(i)+",");
}
System.out.print("\n由后向前输出:");
for(int i=allList.size()-1;i>=0;i--){
System.out.print(allList.get(i)+",");
}
由前向后输出:YuuW24k,Sad,or,Happy,Hello,World,Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 6, Size: 6
at java.util.ArrayList.rangeCheck(Unknown Source)
at java.util.ArrayList.get(Unknown Source)
at ArrayListDemo03.main(ArrayListDemo03.java:20)还是不行哦~
System.out.print(allList.get(i) + ",");
}
System.out.print("\n由后向前输出:");
for (int i = allList.size()-1; i >= 0; i--) {
System.out.print(allList.get(i) + ",");
}
你是没有减1吧
for (int i = allList.size()-1; i >= 0; i--) {
System.out.print(allList.get(i) + ",");
}