我想获取年龄大于32且地址为city2的DataObj对象。
怎么这样过滤呢?
以下是尝试过的代码。
package com.company;
import java.util.ArrayList;
public class Main {
public static void main(String[] args) {
ArrayList<DataObj> arr_datalist = new ArrayList<DataObj>();
ArrayList<DataObj> arr_filteredlist;
arr_datalist.add(new DataObj(1, "aka", 30, "city1"));
arr_datalist.add(new DataObj(2, "akb", 31, "city2"));
arr_datalist.add(new DataObj(3, "akc", 32, "city2"));
arr_datalist.add(new DataObj(4, "akd", 33, "city1"));
arr_datalist.add(new DataObj(5, "ake", 34, "city3"));
// age greater than 32 and address is city2.
arr_filteredlist = arr_datalist.filter(???);
}
}
class DataObj {
int i_id;
String str_name;
int i_age;
String str_address;
DataObj(int id, String name, int age, String address) {
this.i_id = id;
this.str_name = name;
this.i_age = age;
this.str_address = address;
}
}
最佳答案
您有几个常见的选项:
自己动手:
List<DataObj> arr_filteredlist = new ArrayList<>();
for(DataObj e : arr_datalist) {
if(e.i_age > 32 && e.str_address.equals("city2")) {
arr_filteredlist.add(e);
}
}
Guava :
Collection<DataObj> filteredColl = Collections2.filter(arr_datalist,
new Predicate<DataObj>() {
@Override
boolean apply(DataObj e) {
return e.i_age > 32 && e.str_address.equals("city2");
}
// + overrides equals
});
List<DataObj> arr_filteredlist = new ArrayList<>(filteredColl);
Java 8:
List<DataObj> arr_filteredlist =
arr_datalist.stream()
.filter(e-> e.i_age > 32 && e.str_address.equals("city2"))
.collect(Collectors.toList());
关于java - 如何使用多成员变量条件过滤ArrayList?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20375017/