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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Frameset//EN""http://www.w3.org/TR/REC-html40/frameset.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc on Thu Apr 27 23:36:59 PDT 2000 --><TITLE>Java 2 Platform SE v1.3: Class Random</TITLE><LINK REL ="stylesheet" TYPE="text/css" HREF="../../stylesheet.css" TITLE="Style"></HEAD><BODY BGCOLOR="white"><!-- ========== START OF NAVBAR ========== --><A NAME="navbar_top"><!-- --></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0"><TR><TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3"> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="class-use/Random.html"><FONT CLASS="NavBarFont1"><B>Use</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../index-files/index-1.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM><b>Java<sup><font size=-2>TM</font></sup> 2 Platform<br>Std. Ed. v1.3</b></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../java/util/PropertyResourceBundle.html"><B>PREV CLASS</B></A> <A HREF="../../java/util/ResourceBundle.html"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html" TARGET="_top"><B>FRAMES</B></A> <A HREF="Random.html" TARGET="_top"><B>NO FRAMES</B></A></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: INNER | FIELD | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><!-- =========== END OF NAVBAR =========== --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">java.util</FONT><BR>Class Random</H2><PRE><A HREF="../../java/lang/Object.html">java.lang.Object</A> | +--<B>java.util.Random</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD><A HREF="../../java/io/Serializable.html">Serializable</A></DD></DL><DL><DT><B>Direct Known Subclasses:</B> <DD><A HREF="../../java/security/SecureRandom.html">SecureRandom</A></DD></DL><HR><DL><DT>public class <B>Random</B><DT>extends <A HREF="../../java/lang/Object.html">Object</A><DT>implements <A HREF="../../java/io/Serializable.html">Serializable</A></DL><P>An instance of this class is used to generate a stream of pseudorandom numbers. The class uses a 48-bit seed, which is modified using a linear congruential formula. (See Donald Knuth, <i>The Art of Computer Programming, Volume 2</i>, Section 3.2.1.) <p> If two instances of <code>Random</code> are created with the same seed, and the same sequence of method calls is made for each, they will generate and return identical sequences of numbers. In order to guarantee this property, particular algorithms are specified for the class <tt>Random</tt>. Java implementations must use all the algorithms shown here for the class <tt>Random</tt>, for the sake of absolute portability of Java code. However, subclasses of class <tt>Random</tt> are permitted to use other algorithms, so long as they adhere to the general contracts for all the methods. <p> The algorithms implemented by class <tt>Random</tt> use a <tt>protected</tt> utility method that on each invocation can supply up to 32 pseudorandomly generated bits. <p> Many applications will find the <code>random</code> method in class <code>Math</code> simpler to use.<P><DL><DT><B>Since: </B><DD>JDK1.0</DD><DT><B>See Also: </B><DD><A HREF="../../java/lang/Math.html#random()"><CODE>Math.random()</CODE></A>, <A HREF="../../serialized-form.html#java.util.Random">Serialized Form</A></DL><HR><P><!-- ======== INNER CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../java/util/Random.html#Random()">Random</A></B>()</CODE><BR> Creates a new random number generator.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../java/util/Random.html#Random(long)">Random</A></B>(long seed)</CODE><BR> Creates a new random number generator using a single <code>long</code> seed: </TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected int</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#next(int)">next</A></B>(int bits)</CODE><BR> Generates the next pseudorandom number.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextBoolean()">nextBoolean</A></B>()</CODE><BR> Returns the next pseudorandom, uniformly distributed <code>boolean</code> value from this random number generator's sequence.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextBytes(byte[])">nextBytes</A></B>(byte[] bytes)</CODE><BR> Generates random bytes and places them into a user-supplied byte array.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> double</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextDouble()">nextDouble</A></B>()</CODE><BR> Returns the next pseudorandom, uniformly distributed <code>double</code> value between <code>0.0</code> and <code>1.0</code> from this random number generator's sequence.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> float</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextFloat()">nextFloat</A></B>()</CODE><BR> Returns the next pseudorandom, uniformly distributed <code>float</code> value between <code>0.0</code> and <code>1.0</code> from this random number generator's sequence.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> double</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextGaussian()">nextGaussian</A></B>()</CODE><BR> Returns the next pseudorandom, Gaussian ("normally") distributed <code>double</code> value with mean <code>0.0</code> and standard deviation <code>1.0</code> from this random number generator's sequence.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextInt()">nextInt</A></B>()</CODE><BR> Returns the next pseudorandom, uniformly distributed <code>int</code> value from this random number generator's sequence.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextInt(int)">nextInt</A></B>(int n)</CODE><BR> Returns a pseudorandom, uniformly distributed <tt>int</tt> value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> long</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#nextLong()">nextLong</A></B>()</CODE><BR> Returns the next pseudorandom, uniformly distributed <code>long</code> value from this random number generator's sequence.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/util/Random.html#setSeed(long)">setSeed</A></B>(long seed)</CODE><BR> Sets the seed of this random number generator using a single <code>long</code> seed.</TD>⌨️ 快捷键说明
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