简单研究了一下，贴出来，相当于笔记

import java.lang.reflect.*;import java.util.ArrayList;import java.util.List;import java.util.stream.Collectors;import com.google.gson.Gson;public class Hello {    public static void main(String[] args) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {        try {            // Java中Lambda表达式            List
     
       list = new ArrayList
      
       ();            list.add(new Student("zhangsan", 20, "2"));            list.add(new Student("lisi", 22, "2"));            list.add(new Student("zhangjie", 25, "3"));            list.add(new Student("zhangjie", 40, "3"));            // 循环赋值,增加2岁            list.forEach(item -> item.setAge(item.getAge() + 2));            // 循环输出年龄            list.forEach(item -> System.out.println(item.getAge()));            // 总数、最大值、最小值            int ages = list.stream().mapToInt(f -> f.getAge()).sum();            int maxAge = list.stream().mapToInt(f -> f.getAge()).max().getAsInt();            System.err.println("总年龄是:" + ages);            System.err.println("最大年龄是:" + maxAge);            // 分组            list.stream().collect(Collectors.groupingBy(Student::getName, Collectors.toList()))//                    .forEach((name, fooListByName) -> System.out.println(name + " " + new Gson().toJson(fooListByName)));            list.stream().collect(Collectors.groupingBy(Student::getName, Collectors.counting()))//                    .forEach((name, count) -> System.out.println(name + " " + count));            list.stream().collect(Collectors.groupingBy(Student::getName, Collectors.toList()))//                    .forEach((name, ls) -> System.out.println("姓名:" + name + ",最大年龄" + ls.stream().mapToInt(f -> f.getAge()).max().getAsInt()));                                //分页            List
       
         arr = list.stream().skip(0).limit(5).collect(Collectors.toList());                        //where查询            List
        
          list= taskPros.stream().filter(f->f.getFirmId().equals("199989494")&&//                        f.getTaskId().equals("1000")).collect(Collectors.toList());        } finally {        }    }}