EvictingQueue 
  这个是一个非阻塞的队列,当队列长度满了后,自动移除头元素,比如: 

EvictingQueue<String> q = EvictingQueue.create(3); 
q.add("one"); 
q.add("two"); 
q.add("three"); 
q.add("four"); 
// the head of the queue is evicted after adding the fourth element

fileTreeTraverser 文件遍历递归利器 
   这个方法可以快速遍历某个文件目录下的所有文件,比如: 

FluentIterable<File> iterable = Files.fileTreeTraverser().breadthFirstTraversal(new File("/var/tmp")); 
for (File f : iterable) { 
    System.out.println(f.getAbsolutePath()); 
}

其中f.getAbsolutePath()用的是jdk 7中的方法

Google Guava Splitter

Splitter niceCommaSplitter = Splitter.on(',') .omitEmptyString().trimResults();
niceCommaSplitter.split("one,, two,  three"); //"one","two","three"
niceCommaSplitter.split("  four  ,  five  "); //"four","five"

Guava中Joiner的用法: 

int[] numbers = { 1, 2, 3, 4, 5 };  
String numbersAsStringDirectly = Ints.join(";", numbers);

Guava中Splitter的用法:

String testString = "foo , what,,,more,";  
Iterable<String> split = Splitter.on(",").omitEmptyStrings().trimResults().split(testString);

set的交集, 并集, 差集的用法

HashSet setA = newHashSet(1, 2, 3, 4, 5);
HashSet setB = newHashSet(4, 5, 6, 7, 8);
 
SetView union = Sets.union(setA, setB);
System.out.println("union:");
for (Integer integer : union)
    System.out.println(integer);       
 
SetView difference = Sets.difference(setA, setB);
System.out.println("difference:");
for (Integer integer : difference)
    System.out.println(integer);      
 
SetView intersection = Sets.intersection(setA, setB);
System.out.println("intersection:");
for (Integer integer : intersection)
    System.out.println(integer);

针对Map的用法: 

MapDifference differenceMap = Maps.difference(mapA, mapB);

differenceMap.areEqual();
Map entriesDiffering = differenceMap.entriesDiffering();
Map entriesOnlyOnLeft = differenceMap.entriesOnlyOnLeft();
Map entriesOnlyOnRight = differenceMap.entriesOnlyOnRight();
Map entriesInCommon = differenceMap.entriesInCommon();

验证与条件检查 

public PostExample(final String title, final Date date, final String author) {  
    this.title = checkNotNull(title);  
    this.date = checkNotNull(date);  
    this.author = checkNotNull(author);  
}

针对集合中只有一个元素的情况: 
Iterables.getOnlyElement(); 
这个主要是用来替换Set.iterator.next()或 List.get(0), 而且在测试中使用非常方便, 如果出现0个或者2+则直接抛出异常 

ImmutableList.copyOf的用法:

public Directions(Address from, Address to, List<Step> steps) {  
  this.from = from;  
  this.to = to;  
  this.steps = ImmutableList.of(steps);  
}

equals和hashcode的用法: 

public boolean equals(Object o) {
    if (o instanceof Order) {
      Order that = (Order)o;

      return Objects.equal(address, that.address)
          && Objects.equal(targetArrivalDate, that.targetArrivalDate)
          && Objects.equal(lineItems, that.lineItems);
    } else {
      return false;
    }
  }

  public int hashCode() {
    return Objects.hashCode(address, targetArrivalDate, lineItems);
  }