Stream类处理集合能改变集合元素的某个属性吗

[Hello__World1994]

感觉stream处理集合是挺方便的，但是如果的集合是List<Student> 我希望最后返回的还是List<Student> 但是Student的age属性进行+1处理该怎么办，该调用哪个方法

[weixin_41998852]

public static void main(String args[]){
System.out.println("使用 Java 7: ");

// 计算空字符串
List<String> strings = Arrays.asList("abc", "", "bc", "efg", "abcd","", "jkl");
System.out.println("列表: " +strings);
long count = getCountEmptyStringUsingJava7(strings);

System.out.println("空字符数量为: " + count);
count = getCountLength3UsingJava7(strings);

System.out.println("字符串长度为 3 的数量为: " + count);

// 删除空字符串
List<String> filtered = deleteEmptyStringsUsingJava7(strings);
System.out.println("筛选后的列表: " + filtered);

// 删除空字符串，并使用逗号把它们合并起来
String mergedString = getMergedStringUsingJava7(strings,", ");
System.out.println("合并字符串: " + mergedString);
List<Integer> numbers = Arrays.asList(3, 2, 2, 3, 7, 3, 5);

// 获取列表元素平方数
List<Integer> squaresList = getSquares(numbers);
System.out.println("平方数列表: " + squaresList);
List<Integer> integers = Arrays.asList(1,2,13,4,15,6,17,8,19);

System.out.println("列表: " +integers);
System.out.println("列表中最大的数 : " + getMax(integers));
System.out.println("列表中最小的数 : " + getMin(integers));
System.out.println("所有数之和 : " + getSum(integers));
System.out.println("平均数 : " + getAverage(integers));
System.out.println("随机数: ");

// 输出10个随机数
Random random = new Random();

for(int i=0; i < 10; i++){
System.out.println(random.nextInt());
}

System.out.println("使用 Java 8: ");
System.out.println("列表: " +strings);

count = strings.stream().filter(string->string.isEmpty()).count();
System.out.println("空字符串数量为: " + count);

count = strings.stream().filter(string -> string.length() == 3).count();
System.out.println("字符串长度为 3 的数量为: " + count);

filtered = strings.stream().filter(string ->!string.isEmpty()).collect(Collectors.toList());
System.out.println("筛选后的列表: " + filtered);

mergedString = strings.stream().filter(string ->!string.isEmpty()).collect(Collectors.joining(", "));
System.out.println("合并字符串: " + mergedString);

squaresList = numbers.stream().map( i ->i*i).distinct().collect(Collectors.toList());
System.out.println("Squares List: " + squaresList);
System.out.println("列表: " +integers);

IntSummaryStatistics stats = integers.stream().mapToInt((x) ->x).summaryStatistics();

System.out.println("列表中最大的数 : " + stats.getMax());
System.out.println("列表中最小的数 : " + stats.getMin());
System.out.println("所有数之和 : " + stats.getSum());
System.out.println("平均数 : " + stats.getAverage());
System.out.println("随机数: ");

random.ints().limit(10).sorted().forEach(System.out::println);

// 并行处理
count = strings.parallelStream().filter(string -> string.isEmpty()).count();
System.out.println("空字符串的数量为: " + count);
}

private static int getCountEmptyStringUsingJava7(List<String> strings){
int count = 0;

for(String string: strings){

if(string.isEmpty()){
count++;
}
}
return count;
}

private static int getCountLength3UsingJava7(List<String> strings){
int count = 0;

for(String string: strings){

if(string.length() == 3){
count++;
}
}
return count;
}

private static List<String> deleteEmptyStringsUsingJava7(List<String> strings){
List<String> filteredList = new ArrayList<String>();

for(String string: strings){

if(!string.isEmpty()){
filteredList.add(string);
}
}
return filteredList;
}

private static String getMergedStringUsingJava7(List<String> strings, String separator){
StringBuilder stringBuilder = new StringBuilder();

for(String string: strings){

if(!string.isEmpty()){
stringBuilder.append(string);
stringBuilder.append(separator);
}
}
String mergedString = stringBuilder.toString();
return mergedString.substring(0, mergedString.length()-2);
}

private static List<Integer> getSquares(List<Integer> numbers){
List<Integer> squaresList = new ArrayList<Integer>();

for(Integer number: numbers){
Integer square = new Integer(number.intValue() * number.intValue());

if(!squaresList.contains(square)){
squaresList.add(square);
}
}
return squaresList;
}

private static int getMax(List<Integer> numbers){
int max = numbers.get(0);

for(int i=1;i < numbers.size();i++){

Integer number = numbers.get(i);

if(number.intValue() > max){
max = number.intValue();
}
}
return max;
}

private static int getMin(List<Integer> numbers){
int min = numbers.get(0);

for(int i=1;i < numbers.size();i++){
Integer number = numbers.get(i);

if(number.intValue() < min){
min = number.intValue();
}
}
return min;
}

private static int getSum(List numbers){
int sum = (int)(numbers.get(0));

for(int i=1;i < numbers.size();i++){
sum += (int)numbers.get(i);
}
return sum;
}

private static int getAverage(List<Integer> numbers){
return getSum(numbers) / numbers.size();
}
}

[weixin_41998852]

package com.csii.lqk;


import java.util.Arrays;
import java.util.List;

/**
* Hello world!
*
*/
public class App
{

public static void main(String[] args) {
List<Student> students = Arrays.asList(new Student(10), new Student(20));
students.stream().
map(student -> {student.setAge(student.getAge()+1);return student;}).
forEach(student -> System.out.println(student));


}

}
class Student{
Student(int age){
this.age=age;
}
private int age;

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

@Override
public String toString() {
return "Student{" +
"age=" + age +
'}';
}
}

[沁海棠]

map

[kkkkk0lllll]

list.stream().forEach(x->{x.age+=1;});

[快叫我java小菜鸟]

list = list.stream().map(s -> s.setAge(s.getAge() + 1)).collect(Collectors.toList());