Guava使用笔记系列之集合工具的高…

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package com.qunar.google.guava.collections;

import com.google.common.base.Function;

import com.google.common.base.Predicate;

import com.google.common.base.Strings;

import com.google.common.collect.FluentIterable;

import com.google.common.collect.Iterables;

import com.google.common.collect.Lists;

import com.google.common.collect.Sets;

import com.qunar.google.guava.User;

import java.util.*;

public class CollectionBuilder {

    public static voidmain(String[] args) {

       testBuildCollection();

       testFluentIterable();

       testDifferenceSet();

    }

    private static voidtestBuildCollection() {

       Set userSet = Sets.newConcurrentHashSet();

       HashSet

    }

    private static voidtestFluentIterable(){

       ArrayList stringArrayList =Lists.newArrayList("1", "2", "3", "4","1","1","2");

       int frequency =Iterables.frequency(stringArrayList, "1");

       System.out.println(frequency);

       List userList = Lists.transform(stringArrayList,new Function() {

          @Override

           publicUser apply(String s) {

              User user = new User();

              user.setId(newRandom().nextInt(30)+"");

              user.setAddress(s);

             user.setName(Strings.repeat(s,new Random().nextInt(5)+1));

              return user;

           }

       });

       Iterable idGreaterThanTen =Iterables.filter(userList, new Predicate() {

          @Override

           publicboolean apply(User user) {

              return user.getId().length()> 10;

           }

       });

       for (User user : idGreaterThanTen) {

          System.out.println("id="+user.getId()+"name"+user.getName());

       }

    }

    private static void testDifferenceSet(){

       HashSet firstStringSet = Sets.newHashSet("11","21", "31", "41", "5");

       HashSet secondString = Sets.newHashSet("31","41", "1");

       Sets.SetView difference =Sets.difference(firstStringSet, secondString);

       for (String s : difference) {

          System.out.println(s);

       }

       ArrayList list =Lists.newArrayList(difference);

       for (String s : list) {

          System.out.println(s);

       }

       Sets.SetView intersection =Sets.intersection(firstStringSet, secondString);

       for (String s : intersection) {

          System.out.println(s);

       }

    }

}