Java8 Foreach操作

for (Map.Entry String, Integer entry : items.entrySet()) { System.out.println("Item : " + entry.getKey() + " Count : " + entry.getValue()); }

1.2 使用Java8的foreach+lambda表达式遍历Map

Map String, Integer items = new HashMap ();

items.put("A", 10);

items.put("B", 20);

items.put("C", 30);

items.put("D", 40);

items.put("E", 50);

items.put("F", 60);

items.forEach((k,v)- System.out.println("Item : " + k + " Count : " + v));

items.forEach((k,v)- {

 System.out.println("Item : " + k + " Count : " + v);

 if("E".equals(k)){

 System.out.println("Hello E");

});

###2. Foreach操作List
2.1 普通方式循环List

List String items = new ArrayList ();

items.add("A");

items.add("B");

items.add("C");

items.add("D");

items.add("E");

for(String item : items){

 System.out.println(item);

}

2.2 在Java8中使用foreach+lambda表达式遍历List

List String items = new ArrayList ();

items.add("A");

items.add("B");

items.add("C");

items.add("D");

items.add("E");

//lambda

//Output : A,B,C,D,E

items.forEach(item- System.out.println(item));

//Output : C

items.forEach(item- {

 if("C".equals(item)){

 System.out.println(item);

//method reference

//Output : A,B,C,D,E

items.forEach(System.out::println);

//Steam and filter

//Output : B

items.stream()

 .filter(s- s.contains("B"))

 .forEach(System.out::println);

参考资料：

Java 8 Iterable forEach JavaDoc Java 8 forEach JavaDoc

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