public class ForeachTag extends BodyTagSupport {
//存放資料源
private List<?> items;
//每次循環擷取的對象放入pageContext中，并以var屬性的值為key進行儲存
//示例： 頁面上标簽var屬性指定為item，則每次循環取出的對象（obj）将執行如下：
//pageContext.setAttribute("item", obj);
//頁面中可以使用EL表達式取出對象中的屬性, 如： ${item.name}
private String var;
public List<?> getItems() {
return items;
}
public void setItems(List<?> items) {
this.items = items;
}
public String getVar() {
return var;
}
public void setVar(String var) {
this.var = var;
}
@Override
public int doStartTag() {
if(Objects.isNull(this.items) || this.items.size() == 0) {
return SKIP_BODY;
}
Iterator<?> iterator = this.items.iterator();
Object obj = iterator.next();
this.pageContext.setAttribute(var, obj);
this.pageContext.setAttribute("iterator", iterator);
return EVAL_BODY_INCLUDE;
}
@Override
public int doAfterBody() {
Iterator<?> it = (Iterator<?>)this.pageContext.getAttribute("iterator");
if(it.hasNext()) {
this.pageContext.setAttribute(var, it.next());
return EVAL_BODY_AGAIN;
}
return SKIP_BODY;
}
}
2.測試資料輔助類：
2.1.實體類：
public class Book {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
2.1.list集合類：
public class TestData {
public static List<Book> getBooks() {
List<Book> books = new ArrayList<>();
Book b1 = new Book();
b1.setId(1);
b1.setName("水浒傳");
Book b2 = new Book();
b2.setId(2);
b2.setName("紅樓夢");
Book b3 = new Book();
b3.setId(3);
b3.setName("西遊記");
books.add(b1);
books.add(b2);
books.add(b3);
return books;
}
}
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