如何在 Java 中搜索列表?
javaobject oriented programmingprogramming更新于 2024/12/31 6:36:17
流可用于搜索列表中的项目。
Student student2 = list.stream().filter(s -> {return s.getRollNo() == rollNo);}).findAny().orElse(null);
在此示例中，我们按学号搜索学生。
示例
以下示例展示了如何使用流搜索列表中的项目 −
package com.tutorialspoint;
import java.util.ArrayList;
import java.util.List;
public class CollectionsDemo {
public static void main(String[] args) {
List<Student> list = new ArrayList<>();
list.add(new Student(1, "Zara"));
list.add(new Student(2, "Mahnaz"));
list.add(new Student(3, "Ayan"));
System.out.println("List: " + list);
final int rollNoToSearch = 3;
Student student = list.stream().filter(s -> {return s.getRollNo() == rollNoToSearch;}).findAny().orElse(null);
System.out.println(student);
final int rollNoToSearch1 = 4;
student = list.stream().filter(s -> {return s.getRollNo() == rollNoToSearch1;}).findAny().orElse(null);
System.out.println(student);
}
}
class Student {
private int rollNo;
private String name;
public Student(int rollNo, String name) {
this.rollNo = rollNo;
this.name = name;
}
public int getRollNo() {
return rollNo;
}
public void setRollNo(int rollNo) {
this.rollNo = rollNo;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public boolean equals(Object obj) {
if(!(obj instanceof Student)) {
return false;
}
Student student = (Student)obj;
return this.rollNo == student.getRollNo() && this.name.equals(student.getName());
}
@Override
public String toString() {
return "[" + this.rollNo + "," + this.name + "]";
}
}
输出
这将产生以下结果 −
List: [[1,Zara], [2,Mahnaz], [3,Ayan]] [3,Ayan] null
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有用资源
java 参考教程 - 该教程包含有关 java 的更多信息:https://www.cainiaomax.com/java/
