英文:
Java: Cannot filter ArrayList using Java-Streams
问题
以下是翻译好的内容：
我遇到的错误
我得到了错误信息：“在类型Stream
我想要做的事情
我试图筛选“xx ArrayList”，但我一直收到这个错误，我不知道为什么。我对Java不太熟悉，所以这可能是我犯的错误。
这是我的代码
import java.util.HashMap;import java.util.ArrayList;import java.util.stream.*;import java.util.Arrays;public class BusCar{// 时间表String time;int platform;ArrayList<Car> xx = new ArrayList<Car>();String newline = System.getProperty("line.separator");public BusCar(String depTime, int plat){// 初始化实例变量time = depTime;platform = plat;}// 文件名，一个包含火车记录的CSV文件。public void addFromFile(String filename){TrainReader reader = new TrainReader();xx.addAll(reader.getTrains(filename));}public void printBefore(String time){// 打印在给定时间之前出发的所有火车// 每行一个火车xx.stream().filter(i -> Integer.parseInt(i.departureTime) < Integer.parseInt(time)).forEach(i -> System.out.println(i + newline));}}
请注意，我已经进行了必要的修正，使代码在翻译后保持正确的语法和结构。
英文:
The error I am getting
I am getting the error "The method map(Function<? super Car,? extends R>) in the type Stream<Car> is not applicable for the arguments
What I am trying to do
I am trying to filter the xx ArrayList but I keep getting this error and I don not or cannot tell why. I am new to Java so this is probably an error I have made
This is my code
import java.util.HashMap;import java.util.ArrayList;import java.util.stream.*;import java.util.Arrays;public class BusCar{// timetableString time;int platform;ArrayList<Car> xx = new ArrayList<Car>();String newline = System.getProperty("line.separator");public BusCar(String depTime, int plat){// initialise instance variablesdepTime = time;plat = platform;}//filename A CSV file of Train records.public void addFromFile(String filename){TrainReader reader = new TrainReader();xx.addAll(reader.getTrains(filename));}public void printBefore(String time){// prints all trains which depart before the given time// one train per linexx.stream().filter(i -> Integer.parseInt(i.departureTime) < Integer.parseInt(time)).map(i-> System.out.println(i),newline);}}
答案1
得分: 1
看起来您想要这样做。您的Car类需要适当地覆盖toString()方法：
xx.stream().filter(i -> Integer.parseInt(i.departureTime) <Integer.parseInt(time)).forEach(System.out::println);
英文:
It appears you want to do this. Your Car class needs to properly override toString()
xx.stream().filter(i -> Integer.parseInt(i.departureTime) <Integer.parseInt(time)).forEach(System.out::println);</details>
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