play2.0文档-面向java开发者(3)

Manipulating the response 处理应答

Changing the default Content-Type 改变默认内容类型

The result content type is automatically inferred from the Java value you specify as body.

result的内容类型会根据你指定的java值自动推断出来

 

For example:

例如：

Result textResult = ok("Hello World!");




Will automatically set the Content-Type header to text/plain, while:

这将会自动的设置内容类型为 text/plain,而：

 

Result jsonResult = ok(jerksonObject);




will set the Content-Type header to application/json.

将会设置内容类型为 application/json.

 

This is pretty useful, but sometimes you want to change it. Just use theas(newContentType) method on a result to create a new similiar result with a different Content-Type header:

这是十分有用的，如果你想改变它，只需要调用as(newContentType) 方法来创建一个新的result：

 

Result htmlResult = ok("<h1>Hello World!</h1>").as("text/html");




You can also set the content type on the HTTP response:

你也可以设置HTTP应答的内容类型。

public static Result index() {

   response().setContentType("text/html");

   return ok("<h1>Hello World!</h1>");

}

Setting HTTP response headers 设置HTTP应答头

You can add (or update) any HTTP response header:

你可以添加(或更新)任何HTTP应答头：




public static Result index() {

    response().setContentType("text/html");

    response().setHeader(CACHE_CONTROL, "max-age=3600");

    response().setHeader(ETAG, "xxx"); return ok("<h1>Hello World!</h1>");

}




Note that setting an HTTP header will automatically discard any previous value.

注意 设置HTTP头会覆盖当前的值。

 

Setting and discarding cookies 设置和删除cookies

Cookies are just a special form of HTTP headers, but Play provides a set of helpers to make it easier.

Cookies只不过是HTTP头的特定格式，但是play 提供了一系列便利方法：

 

You can easily add a Cookie to the HTTP response:

你可以很容易给HTTP应答添加一个Cookie：

response().setCookie("theme", "blue");




Also, to discard a Cookie previously stored on the Web browser:

你也可以删除已有的Cookie：

 

response().discardCookies("theme");

Specifying the character encoding for text results

指定文本results 的字符编码

For a text-based HTTP response it is very important to handle the character encoding correctly. Play handles that for you and uses utf-8 by default.

正确的处理字符编码对于文本类型的HTTP应答是非常重要的，Play默认用 utf-8 .

 

The encoding is used to both convert the text response to the corresponding bytes to send over the network socket, and to add the proper ;charset=xxx extension to the Content-Type header.

编码即用于把文本应答转换成相应的网络字节码，也为内容类型头添加恰当的 ;charset=xxx 扩展

 

The encoding can be specified when you are generating the Result value:

你可以在生成 Result 值的时候指定编码：

public static Result index() {

   response().setContentType("text/html; charset=iso-8859-1");

   return ok("<h1>Hello World!</h1>", "iso-8859-1");

}