游戏项目中运用到的设计模式（一）装饰者模式

来源：互联网发布：java graphics类详解编辑：程序博客网时间：2024/06/08 04:06

因为项目里面需要对http请求进行多次读取，而HttpServletRequest不支持mark和reset，所以就需要把流存储起来，在每次getInputStream()的时候就用我们自己存储的数据。最开始有两种解决方案：

将inputstream转换成byte数组封装在一个类里面，然后将这个类用ThreadLocal进行存储。
用装饰者模式，而HttpServletRequestWrapper就是装饰模式的典型例子，我们这里只需要新建一个对象继承HttpServletRequestWrapper将对应的方法进行重写即可。

<pre name="code" class="java">import java.io.BufferedReader;import java.io.ByteArrayInputStream;import java.io.IOException;import java.io.InputStreamReader;import javax.servlet.ServletInputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRequestWrapper;public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {private final byte[] body;public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {super(request);int len = request.getContentLength();if(len < 0) len = 0;body = new byte[len];try {request.getInputStream().read(body);} catch (IOException e) {e.printStackTrace();}}@Overridepublic BufferedReader getReader() throws IOException {return new BufferedReader(new InputStreamReader(getInputStream()));}@Overridepublic ServletInputStream getInputStream() throws IOException {final ByteArrayInputStream bais = new ByteArrayInputStream(body);return new ServletInputStream() {@Overridepublic int read() throws IOException {return bais.read();}};}}

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