java8对集合的遍历、过滤、排序

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本文介绍了Java8中如何使用新特性对集合进行更高效的遍历、过滤和排序操作，通过实例代码展示了Stream API的强大功能，提升代码的简洁性和执行效率。

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直接上代码

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

import com.alibaba.fastjson.JSONObject;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

public class Jdk8 {
	public static void main(String[] args) {
		List<Student> list = new ArrayList<Student>();
		list.add(new Student(33, "aaa", "chuangye"));
		list.add(new Student(25, "bbb", "chuangye"));
		list.add(new Student(9, "ccc", "chuangye"));
		list.add(new Student(11, "ddd", "chuangye"));
		//简单遍历
//		list.stream().forEach(stu -> {
//			//此处是对遍历出来的对象进行操作
//			System.out.println(JSONObject.toJSONString(stu));
//			
//			//输出结果
//			/**
//			 *  {"address":"chuangye","age":3,"name":"aaa"}
//			 *	{"address":"chuangye","age":5,"name":"bbb"}
//			 *	{"address":"chuangye","age":9,"name":"ccc"}
//			 *	{"address":"chuangye","age":11,"name":"ddd"}
//			 */
//		});
		
//		//过滤，过滤满足条件的的数据
//		List<Student> resultList = new ArrayList<Student>();
//		resultList = list.stream().filter(e -> !e.getName().equals("bbb")).collect(Collectors.toList());
//		//再遍历出来
//		resultList.stream().forEach(stu -> {
//			System.out.println(JSONObject.toJSONString(stu));
//		});
//		//输出结果
//		{"address":"chuangye","age":3,"name":"aaa"}
//		{"address":"chuangye","age":9,"name":"ccc"}
//		{"address":"chuangye","age":11,"name":"ddd"}
		
		//排序 ， 也需要新的集合接收
		List<Student> resultList = new ArrayList<Student>();
		resultList = list.stream().sorted(Comparator.comparing(Student::getAge)).collect(Collectors.toList());
		
		resultList.stream().forEach(stu -> {
			System.out.println(JSONObject.toJSONString(stu));
		});
		
		//输出结果
		/**
		 * 	{"address":"chuangye","age":9,"name":"ccc"}
		 *	{"address":"chuangye","age":11,"name":"ddd"}
		 *	{"address":"chuangye","age":25,"name":"bbb"}
		 *	{"address":"chuangye","age":33,"name":"aaa"}
		 */
	}
}

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
class Student{
	private int age;
	private String name;
	private String address;
}