import java.util.Objects;
import java.util.function.BiConsumer;/**
*
* @author yangzhilong
* @date 7/15/2019
*/
public class ForEachUtils { /**
*
* @param <T>
* @param startIndex 开始遍历的索引
* @param elements 集合
* @param action
*/
public static <T> void forEach(int startIndex,Iterable<? extends T> elements, BiConsumer<Integer, ? super T> action) {
Objects.requireNonNull(elements);
Objects.requireNonNull(action);
if(startIndex < 0) {
startIndex = 0;
}
int index = 0;
for (T element : elements) {
index++;
if(index <= startIndex) {
continue;
} action.accept(index-1, element);
}
}
}
使用:
ForEachUtils.forEach(0, list, (index, item) -> {});
说明:第一个参数为起始索引,第二个是要遍历的集合,第三个参数为BiConsumer类型的处理器。
单元测试:
import java.util.Arrays;
import java.util.List;import org.junit.Test;import lombok.extern.slf4j.Slf4j;/**
* @author yangzhilong
* @date 7/15/2019
*/
@Slf4j
public class ForEachUtilsTest {
@Test
public void test() {
List<String> list = Arrays.asList("1","2", "3");
ForEachUtils.forEach(0, list, (index, item) -> {
log.info(index + " - " + item);
});
}
@Test
public void test1() {
List<String> list = Arrays.asList("x","y", "z");
ForEachUtils.forEach(1, list, (index, item) -> {
log.info(index + " - " + item);
});
}
}
输出:
0 - 1
1 - 2
2 - 3
1 - y
2 - z