在Java中从子类的父类中过滤出记录

// 父类
class Record {
    private String content;

    public Record(String content) {
        this.content = content;
    }

    public String getContent() {
        return content;
    }
}

// 子类
class FilteredRecord extends Record {
    public FilteredRecord(String content) {
        super(content);
    }

    @Override
    public String getContent() {
        // 过滤逻辑，这里只返回以"A"开头的记录
        if (super.getContent().startsWith("A")) {
            return super.getContent();
        } else {
            return null;
        }
    }
}

public class Main {
    public static void main(String[] args) {
        Record[] records = new Record[3];
        records[0] = new FilteredRecord("Apple");
        records[1] = new FilteredRecord("Banana");
        records[2] = new FilteredRecord("Carrot");

        for (Record record : records) {
            if (record != null) {
                System.out.println(record.getContent());
            }
        }
    }
}