代码块
GetElementFromList.java
package com.example.demo.util;
import com.example.demo.entity.UserPO;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
public class GetElementFromList {
public static void main(String[] args) {
//1. 初始化数据
UserPO user1 = new UserPO(1, "java");
UserPO user2 = new UserPO(2, "C");
UserPO user3 = new UserPO(3, "PHP");
List<UserPO> users = new ArrayList<>();
users.add(user1);
users.add(user2);
users.add(user3);
//2. 获取list集合中的某个元素
List<Integer> ids = users.stream().map(user -> user.getId()).collect(Collectors.toList());
//3. 遍历
ids.forEach(System.out::println);
}
}
UserPO.java
package com.example.demo.entity;
public class UserPO {
private Integer id;
private String name;
public UserPO(Integer id, String name) {
this.id = id;
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
输出
1
2
3
这篇博客通过代码示例展示了如何在Java中利用Lambda表达式从集合对象中提取并获取特定属性的所有值。
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