List集合在Java日常开发中是必不可少的，只要懂得运用各种各样的方法就可以大大提高我们开发的效率，适当活用各种方法才会使我们开发事半功倍。
我总结了三种List集合的遍历方式，下面一一来介绍。
首先来创建一个实体类，以供下面使用。
public class News{
private int id;
private String title;
private String author;
public News(int id, String title, String author) {
super();
this.id = id;
this.title = title;
this.author = author;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
}
第一种、最基础的遍历方式：for循环，指定下标长度，使用List集合的size()方法，进行for循环遍历
import java.util.ArrayList;
public class Demo01 {
public static void main(String[] args) {
ArrayList<News> list = new ArrayList<News>();
list.add(new News(1,"list1","a"));
list.add(new News(2,"list2","b"));
list.add(new News(3,"list3","c"));
list.add(new News(4,"list4","d"));
for (int i = 0; i < list.size(); i++) {
News s = (News)list.get(i);
System.out.println(s.getId()+" "+s.getTitle()+" "+s.getAuthor());
}
}
}
第二种、较为简洁的遍历方式：使用foreach遍历List，但不能对某一个元素进行操作（这种方法在遍历数组和Map集合的时候同样适用）
import java.util.ArrayList;
public class Demo02 {
public static void main(String[] args) {
ArrayList<News> list = new ArrayList<News>();
list.add(new News(1,"list1","a"));
list.add(new News(2,"list2","b"));
list.add(new News(3,"list3","c"));
list.add(new News(4,"list4","d"));
for (News s : list) {
System.out.println(s.getId()+" "+s.getTitle()+" "+s.getAuthor());
}
}
}
第三种、适用迭代器Iterator遍历：直接根据List集合的自动遍历
import java.util.ArrayList;
public class Demo03 {
public static void main(String[] args) {
ArrayList<News> list = new ArrayList<News>();
list.add(new News(1,"list1","a"));
list.add(new News(2,"list2","b"));
list.add(new News(3,"list3","c"));
list.add(new News(4,"list4","d"));
Iterator<News> iter = list.iterator();
while (iter.hasNext()) {
News s = (News) iter.next();
System.out.println(s.getId()+" "+s.getTitle()+" "+s.getAuthor());
}
}
}
上面三种遍历方式差别不是特别大，在没有特定的要求时，均可以使用。不过根据不同的特殊情况，要合理选择方式，来提高开发的效率。