guava的一些用法

 package guavaTest;

 import com.google.common.base.CharMatcher;
 import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.Lists;
 import com.google.common.primitives.Ints;
 import com.google.common.util.concurrent.*;
 import org.checkerframework.checker.nullness.compatqual.NullableDecl;

 import java.util.List;
 import java.util.Random;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;

 /**
  * Google guava 的使用
  */
 public class GuavaTest {

     //连接器(对于Joiner，常用的方法是   跳过NULL元素：skipNulls()  /  对于NULL元素使用其他替代：useForNull(String))
     // private static final Joiner joiner = Joiner.on(",").skipNulls();
     private static final Joiner joiner = Joiner.on(",").useForNull("我是空字符串");

     //分割器(对于Splitter，常用的方法是：trimResults()/omitEmptyStrings()。注意拆分的方式，有字符串，还有正则，还有固定长度分割（太贴心了！）)
     private static final Splitter splitter = Splitter.on(",").trimResults().omitEmptyStrings();

     public static void main(String[] args) {

         String join = joiner.join(Lists.newArrayList("a", null, "b"));
         System.out.println("join:" + join);

         // a,  ,b,,
         for (String tmp : splitter.split("bb,lll,kkk,,,,,,,,")) {
             System.out.println("|" + tmp + "|");
         }

         List<Integer> integers = Ints.asList(1, 2, 3, 4, 5, 6);

         System.out.println(Ints.join(",", 1, 2, 3, 4));

         //原生数组类型快速合并
         int[] concat = Ints.concat(new int[]{1, 2, 3}, new int[]{7, 8, 9});
         System.out.println(concat.length);

         //求最大、最小
         System.out.println(Ints.max(concat) + "" + Ints.min(concat));

         //是否包含，不用循环查找了
         System.out.println(Ints.contains(concat, 9));

         //集合到数组的转换
         System.out.println(Ints.toArray(integers));

         //Map<String,List<String>>
         ArrayListMultimap<String, String> listMultimap = ArrayListMultimap.create();

         listMultimap.put("张晓明", "数学");
         listMultimap.put("张晓明", "语文");
         listMultimap.put("张晓明", "物理");
         listMultimap.put("王小二", "英语");

         test();

     }

     public static void test() {

         ExecutorService service = Executors.newFixedThreadPool(10);
         ListeningExecutorService listeningExecutorService = MoreExecutors.listeningDecorator(service);
         ListenableFuture<Integer> listenableFuture = listeningExecutorService.submit(() -> {

             if (new Random().nextInt(3) == 2) {
                 throw new NullPointerException();
             }
             return 1;

         });

         FutureCallback<Integer> futureCallback = new FutureCallback<Integer>() {

             @Override
             public void onSuccess(@NullableDecl Integer result) {
                 System.out.println("---------" + result);
             }

             @Override
             public void onFailure(Throwable t) {
                 System.out.println("------------" + t.getMessage());
             }

         };

         Futures.addCallback(listenableFuture, futureCallback);

     }

 }