Java 7
比較容易忘記的特色
Diamond Operator
Diamond Operator
Map<String,List<String>> anagrams = new HashMap<String,List<String>>();
// Dimanod
Map<String,List<String>> anagrams = new HashMap<>();
Switch 裡面
可以使用字串
Switch 裡面 可以使用字串
// Jobd is match 領班(101), 組長(102), 助理(214)
if ("101".equals(userEjobd)) {
jobdCheck = true;
} else if ("102".equals(userEjobd)) {
jobdCheck = true;
} else if ("214".equals(userEjobd)) {
jobdCheck = true;
}Switch 裡面 可以使用字串
switch(userEjobd) {
case "101":
case "102":
case "214":
jobdCheck = true;
}Switch 裡面 可以使用字串
public class Test
{
public static void main(String[] args)
{
String str = "two";
switch(str)
{
case "one":
System.out.println("one");
break;
case "two":
System.out.println("two");
break;
case "three":
System.out.println("three");
break;
default:
System.out.println("no match");
}
}
} 自動資源管理
Try-with-resource
自動資源管理
public static void main(String[] args) {
BufferedReader br = null;
String line;
try {
br = new BufferedReader(new FileReader("C:\\testing.txt"));
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null) br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}自動資源管理
public static void main(String[] args) {
String line;
try (BufferedReader br = new BufferedReader(
new FileReader("C:\\testing.txt"))) {
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
// br will be closed automatically
}帶底線的數字表現形式
帶底線的數字表現形式
int thousand = 1_000;
int million = 1_000_000
串起來的 Exception
串起來的 Exception
public voidoldMultiCatch() {
try{
methodThatThrowsThreeExceptions();
} catch(ExceptionOne e) {
// log and deal with ExceptionOne
} catch(ExceptionTwo e) {
// log and deal with ExceptionTwo
} catch(ExceptionThree e) {
// log and deal with ExceptionThree
}
}串起來的 Exception
public voidnewMultiCatch() {
try{
methodThatThrowsThreeExceptions();
} catch(ExceptionOne | ExceptionTwo | ExceptionThree e) {
// log and deal with all Exceptions
}
}Java 7 比較容易忘記的特色
By Balicanta Yao
Java 7 比較容易忘記的特色
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