Java 1.7 里有什么？

下面是Java 1.7 里新出现的功能的一些用法例子:

对集合的支持

创建List / Set / Map 时写法更简单了。

 
List< String> list = [string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"item"];
 
String item = list[0];
 
Set< String > set = {string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"item"};
 
Map< String,Integer > map = {string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"key" : 1};
 
int value = map[string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"key"];

对资源的自动回收管理

下面的代码看起来有点麻烦 … 不是吗

 
BufferedReader br = new BufferedReader(new FileReader(path));
 
try {
 
   return br.readLine();
 
} finally {
 
   br.close();
 
}

相信你一定会喜欢下面这种写法

 
try (BufferedReader br = new BufferedReader(newFileReader(path)) {
 
   return br.readLine();
 
}

泛型实例创建过程中类型引用的简化

当声明你的对象的接口是，你肯定是不想重复指明泛型类型
看看下面的这种写法多好呀…

`1`	`Map<String,String> hello =` `new` `HashMap<>();`

在数字中使用下划线

`1`	`int` `billion = 1_000_000_000;`

我不知道这个能有多少用处

对字符串进行switch case

 
String availability = string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"available";
 
switch(availability) {
 
 case string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"available":
 
    //code
 
    break; 
 
 
 
  case string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"unavailable":
 
    //code
 
    break; 
 
 
 
  case string" style="background-color:initial!important; border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-width:0px!important; border-style:initial; border-color:initial; margin-top:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-left:0px!important; padding-top:0px!important; padding-right:0px!important; padding-bottom:0px!important; padding-left:0px!important; vertical-align:baseline!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; border-style:initial!important; border-color:initial!important; outline-width:0px!important; outline-style:initial!important; outline-color:initial!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-size:13px; direction:ltr!important; display:inline!important; color:blue!important">"merged":
 
    //code 
 
 
 
  default:
 
    //code
 
    break;
 
}

注意：在把字符串传进Switch case之前，别忘了检查字符串是否为Null。

二进制符号

你可用作二进制字符前加上 0b 来创建一个二进制类型。

`1`	`int` `binary = 0b1001_1001;`

一个catch里捕捉多个异常类型

 
try {
 
Here comes your code....
 
}
 
catch(IOException | NullPointerException | ..........) {
 
}

如果有人能说出更多的新特征，那就更好了。我相信里面有更多的很酷的新东西。

来源:http://www.aqee.net/whas-up-in-java-1-7/

Java 1.7 里有什么？

对集合的支持

对资源的自动回收管理

泛型实例创建过程中类型引用的简化

在数字中使用下划线

对字符串进行switch case

二进制符号

一个catch里捕捉多个异常类型

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