例1 用lambda表达式实现Runnable

 public static void main(String[] args) {Runnable runnable = () -> System.out.println("This is Lambda Test!");Thread thread = new Thread(runnable);thread.start();
}
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例2 使用Java 8 lambda表达式进行事件处理

 public static void main(String[] args) {JButton show = new JButton("Show");show.addActionListener((e) -> {System.out.println("This is Lambda Sample For Action");});
}
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例3 使用lambda表达式对列表进行迭代

 public static void main(String[] args) {List<String> features = Arrays.asList("Lambdas", "Default Method", "Stream API", "Date and Time API");features.forEach(n -> System.out.println(n));
}
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例4 使用lambda表达式和函数式接口Predicate

 public static void main(String[] args) {List<String> languages = Arrays.asList("Java", "Scala", "C++", "Haskell", "Lisp");System.out.println("Languages which starts with J :");filter(languages, (str)->str.startsWith("J"));System.out.println("Languages which ends with a ");filter(languages, (str)->str.endsWith("a"));System.out.println("Print all languages :");filter(languages, (str)->true);System.out.println("Print no language : ");filter(languages, (str)->false);System.out.println("Print language whose length greater than 4:");filter(languages, (str)->str.length() > 4);
}public static void filter(List<String> names, Predicate<String> condition) {names.stream().filter(name->condition.test(name)).forEach(name-> System.out.println(name));
}
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例5 如何在lambda表达式中加入Predicate

 public static void main(String[] args) {List<String> languages = Arrays.asList("Java", "Scala", "Basic", "Haskell", "Lisp");Predicate<String> startWithJ = n->n.startsWith("J");Predicate<String> fourLengthLetter = n->n.length() == 4;languages.stream().filter(startWithJ.and(fourLengthLetter)).forEach(n-> System.out.println("nName, which starts with 'J' and four letter long is : " + n));Predicate<String> endWithA = n->n.endsWith("a");Predicate<String> fiveLengthLetter = n->n.length() == 5;languages.stream().filter(endWithA.or(fiveLengthLetter)).forEach(n-> System.out.println("nName, which end with 'a' or five letter long is : " + n));
}
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例6 Java 8中使用lambda表达式的Map和Reduce示例

 public static void main(String[] args) {List<Integer> costBeforeTax = Arrays.asList(100, 200, 300, 400);costBeforeTax.stream().map(cost->cost + .12*cost).forEach(cost-> System.out.println(cost));double bill = costBeforeTax.stream().map(cost->cost + .12*cost).reduce((sum, cost)->sum + cost).get();System.out.println("Total:" + bill);
}
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例7 通过过滤创建一个String列表

 public static void main(String[] args) {List<String> strList = Arrays.asList("abcd", "abcde", "abc", "ab");List<String> filtered = strList.stream().filter(x->x.length()>2).collect(Collectors.toList());System.out.printf("Original List : %s, filtered list : %s %n", strList, filtered);
}
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例8 对列表的每个元素应用函数

 public static void main(String[] args) {List<String> G7 = Arrays.asList("USA", "Japan", "France", "Germany", "Italy", "U.K.","Canada");String G7Countries = G7.stream().map(x -> x.toUpperCase()).collect(Collectors.joining(", "));System.out.println(G7Countries);
}
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例9 复制不同的值，创建一个子列表

 public static void main(String[] args) {List<Integer> numbers = Arrays.asList(9, 10, 3, 4, 7, 3, 4);List<Integer> distinct = numbers.stream().map(i->i*i).distinct().collect(Collectors.toList());System.out.printf("Original List : %s,  Square Without duplicates : %s %n", numbers, distinct);
}
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例10 计算集合元素的最大值、最小值、总和以及平均值

 public static void main(String[] args) {List<Integer> primes = Arrays.asList(2, 3, 5, 7, 11, 13, 17, 19, 23, 29);IntSummaryStatistics stats = primes.stream().mapToInt(x->x).summaryStatistics();System.out.println("Highest prime number in List : " + stats.getMax());System.out.println("Lowest prime number in List : " + stats.getMin());System.out.println("Sum of all prime numbers : " + stats.getSum());System.out.println("Average of all prime numbers : " + stats.getAverage());
}
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附：源码地址