从上面的代码中可以清晰的看到JSP内建的几个对象（out、request、response、session、pageContext、application、config、page）是怎么产生的，懂servlet的朋友一看就能明白。
下面重点理解一下out对象，它被声明为JspWriter类型，JspWriter是一个抽象类，在包javax.servlet.jsp中可以找到它的定义。
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abstractpublicclassjavax.servlet.jsp.JspWriterextends java.io.Writer{
final public static intNO_BUFFER = 0;
final public static intDEFAULT_BUFFER = -1;
final public static intUNBOUNDED_BUFFER = -2;
protected intbufferSize;
protected BooleanautoFlush;
protectedjavax.servlet.jsp.JspWriter(intarg1,booleanarg2);
abstractpublicvoidnewLine()throwsIOException;
abstractpublicvoidprint(booleanarg0)throwsIOException;
abstractpublicvoidprint(chararg0)throwsIOException;
abstractpublicvoidprint(intarg0)throwsIOException;
abstractpublicvoidprint(longarg0)throwsIOException;
abstractpublicvoidprint(floatarg0)throwsIOException;
abstractpublicvoidprint(doublearg0)throwsIOException;
abstractpublicvoidprint(char[]arg0)throwsIOException;
abstractpublicvoidprint(Stringarg0)throwsIOException;
abstractpublicvoidprint(Objectarg0)throwsIOException;
abstractpublicvoidprintln()throwsIOException;
abstractpublicvoidprintln(booleanarg0)throwsIOException;
abstractpublicvoidprintln(chararg0)throwsIOException;
abstractpublicvoidprintln(intarg0)throwsIOException;
abstractpublicvoidprintln(longarg0)throwsIOException;
abstractpublicvoidprintln(floatarg0)throwsIOException;
abstractpublicvoidprintln(doublearg0)throwsIOException;
abstractpublicvoidprintln(char[]arg0)throwsIOException;
abstractpublicvoidprintln(Stringarg0)throwsIOException;
abtractpublicvoidprintln(Objectarg0)throwsIOException;
abstractpublicvoidclear()throwsIOException;
abstractpublicvoidclearBuffer()throwsIOException;
abstractpublicvoidflush()throwsIOException;
abstractpublicvoidclose()throwsIOException;
publicintgetBufferSize() ;
abstractpublicintgetRemaining();
publicbooleanisAutoFlush();
} |
