stringbuffer.html

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public int <B>codePointAt</B>(int&nbsp;index)</PRE>
<DL>
<DD>Returns the character (Unicode code point) at the specified
 index. The index refers to <code>char</code> values
 (Unicode code units) and ranges from <code>0</code> to
 <A HREF="StringBuffer.html#length()"><CODE>length()</CODE></A><code> - 1</code>.

 <p> If the <code>char</code> value specified at the given index
 is in the high-surrogate range, the following index is less
 than the length of this sequence, and the
 <code>char</code> value at the following index is in the
 low-surrogate range, then the supplementary code point
 corresponding to this surrogate pair is returned. Otherwise,
 the <code>char</code> value at the given index is returned.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>index</CODE> - the index to the <code>char</code> values
<DT><B>返回：</B><DD>the code point value of the character at the
             <code>index</code><DT><B>从以下版本开始：</B></DT>
  <DD>1.5</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="codePointBefore(int)"><!-- --></A><H3>
codePointBefore</H3>
<PRE>
public int <B>codePointBefore</B>(int&nbsp;index)</PRE>
<DL>
<DD>Returns the character (Unicode code point) before the specified
 index. The index refers to <code>char</code> values
 (Unicode code units) and ranges from <code>1</code> to <A HREF="StringBuffer.html#length()"><CODE>length()</CODE></A>.

 <p> If the <code>char</code> value at <code>(index - 1)</code>
 is in the low-surrogate range, <code>(index - 2)</code> is not
 negative, and the <code>char</code> value at <code>(index -
 2)</code> is in the high-surrogate range, then the
 supplementary code point value of the surrogate pair is
 returned. If the <code>char</code> value at <code>index -
 1</code> is an unpaired low-surrogate or a high-surrogate, the
 surrogate value is returned.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>index</CODE> - the index following the code point that should be returned
<DT><B>返回：</B><DD>the Unicode code point value before the given index.<DT><B>从以下版本开始：</B></DT>
  <DD>1.5</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="codePointCount(int, int)"><!-- --></A><H3>
codePointCount</H3>
<PRE>
public int <B>codePointCount</B>(int&nbsp;beginIndex,
                          int&nbsp;endIndex)</PRE>
<DL>
<DD>Returns the number of Unicode code points in the specified text
 range of this sequence. The text range begins at the specified
 <code>beginIndex</code> and extends to the <code>char</code> at
 index <code>endIndex - 1</code>. Thus the length (in
 <code>char</code>s) of the text range is
 <code>endIndex-beginIndex</code>. Unpaired surrogates within
 this sequence count as one code point each.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>beginIndex</CODE> - the index to the first <code>char</code> of
 the text range.<DD><CODE>endIndex</CODE> - the index after the last <code>char</code> of
 the text range.
<DT><B>返回：</B><DD>the number of Unicode code points in the specified text
 range<DT><B>从以下版本开始：</B></DT>
  <DD>1.5</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="offsetByCodePoints(int, int)"><!-- --></A><H3>
offsetByCodePoints</H3>
<PRE>
public int <B>offsetByCodePoints</B>(int&nbsp;index,
                              int&nbsp;codePointOffset)</PRE>
<DL>
<DD>Returns the index within this sequence that is offset from the
 given <code>index</code> by <code>codePointOffset</code> code
 points. Unpaired surrogates within the text range given by
 <code>index</code> and <code>codePointOffset</code> count as
 one code point each.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>index</CODE> - the index to be offset<DD><CODE>codePointOffset</CODE> - the offset in code points
<DT><B>返回：</B><DD>the index within this sequence<DT><B>从以下版本开始：</B></DT>
  <DD>1.5</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="getChars(int, int, char[], int)"><!-- --></A><H3>
getChars</H3>
<PRE>
public void <B>getChars</B>(int&nbsp;srcBegin,
                     int&nbsp;srcEnd,
                     char[]&nbsp;dst,
                     int&nbsp;dstBegin)</PRE>
<DL>
<DD>Characters are copied from this sequence into the 
 destination character array <code>dst</code>. The first character to 
 be copied is at index <code>srcBegin</code>; the last character to 
 be copied is at index <code>srcEnd-1</code>. The total number of 
 characters to be copied is <code>srcEnd-srcBegin</code>. The 
 characters are copied into the subarray of <code>dst</code> starting 
 at index <code>dstBegin</code> and ending at index:
 <p><blockquote><pre>
 dstbegin + (srcEnd-srcBegin) - 1
 </pre></blockquote>
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>srcBegin</CODE> - start copying at this offset.<DD><CODE>srcEnd</CODE> - stop copying at this offset.<DD><CODE>dst</CODE> - the array to copy the data into.<DD><CODE>dstBegin</CODE> - offset into <code>dst</code>.
<DT><B>抛出：</B>
<DD><CODE><A HREF="NullPointerException.html" title="java.lang 中的类">NullPointerException</A></CODE> - if <code>dst</code> is 
             <code>null</code>.
<DD><CODE><A HREF="IndexOutOfBoundsException.html" title="java.lang 中的类">IndexOutOfBoundsException</A></CODE> - if any of the following is true:
             <ul>
             <li><code>srcBegin</code> is negative
             <li><code>dstBegin</code> is negative
             <li>the <code>srcBegin</code> argument is greater than 
             the <code>srcEnd</code> argument.
             <li><code>srcEnd</code> is greater than 
             <code>this.length()</code>.
             <li><code>dstBegin+srcEnd-srcBegin</code> is greater than 
             <code>dst.length</code>
             </ul></DL>
</DD>
</DL>
<HR>

<A NAME="setCharAt(int, char)"><!-- --></A><H3>
setCharAt</H3>
<PRE>
public void <B>setCharAt</B>(int&nbsp;index,
                      char&nbsp;ch)</PRE>
<DL>
<DD>The character at the specified index is set to <code>ch</code>. This 
 sequence is altered to represent a new character sequence that is 
 identical to the old character sequence, except that it contains the 
 character <code>ch</code> at position <code>index</code>. 
 <p>
 The index argument must be greater than or equal to 
 <code>0</code>, and less than the length of this sequence.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>index</CODE> - the index of the character to modify.<DD><CODE>ch</CODE> - the new character.
<DT><B>抛出：</B>
<DD><CODE><A HREF="IndexOutOfBoundsException.html" title="java.lang 中的类">IndexOutOfBoundsException</A></CODE> - if <code>index</code> is 
             negative or greater than or equal to <code>length()</code>.<DT><B>另请参见：</B><DD><A HREF="StringBuffer.html#length()"><CODE>length()</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="append(java.lang.Object)"><!-- --></A><H3>
append</H3>
<PRE>
public <A HREF="StringBuffer.html" title="java.lang 中的类">StringBuffer</A> <B>append</B>(<A HREF="Object.html" title="java.lang 中的类">Object</A>&nbsp;obj)</PRE>
<DL>
<DD>Appends the string representation of the <code>Object</code> 
 argument.
 <p>
 The argument is converted to a string as if by the method 
 <code>String.valueOf</code>, and the characters of that 
 string are then appended to this sequence.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>obj</CODE> - an <code>Object</code>.
<DT><B>返回：</B><DD>a reference to this object.<DT><B>另请参见：</B><DD><A HREF="String.html#valueOf(java.lang.Object)"><CODE>String.valueOf(java.lang.Object)</CODE></A>, 
<A HREF="StringBuffer.html#append(java.lang.String)"><CODE>append(java.lang.String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="append(java.lang.String)"><!-- --></A><H3>
append</H3>
<PRE>
public <A HREF="StringBuffer.html" title="java.lang 中的类">StringBuffer</A> <B>append</B>(<A HREF="String.html" title="java.lang 中的类">String</A>&nbsp;str)</PRE>
<DL>
<DD>Appends the specified string to this character sequence.
 <p>
 The characters of the <code>String</code> argument are appended, in 
 order, increasing the length of this sequence by the length of the 
 argument. If <code>str</code> is <code>null</code>, then the four 
 characters <code>"null"</code> are appended.
 <p>
 Let <i>n</i> be the length of this character sequence just prior to 
 execution of the <code>append</code> method. Then the character at 
 index <i>k</i> in the new character sequence is equal to the character 
 at index <i>k</i> in the old character sequence, if <i>k</i> is less 
 than <i>n</i>; otherwise, it is equal to the character at index 
 <i>k-n</i> in the argument <code>str</code>.
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>str</CODE> - a string.
<DT><B>返回：</B><DD>a reference to this object.</DL>
</DD>
</DL>
<HR>

<A NAME="append(java.lang.StringBuffer)"><!-- --></A><H3>
append</H3>
<PRE>
public <A HREF="StringBuffer.html" title="java.lang 中的类">StringBuffer</A> <B>append</B>(<A HREF="StringBuffer.html" title="java.lang 中的类">StringBuffer</A>&nbsp;sb)</PRE>
<DL>
<DD>将指定的 <tt>StringBuffer</tt> 追加到此序列中。
 <p>
按顺序将 <tt>StringBuffer</tt> 参数中的字符追加到此 <tt>StringBuffer</tt> 中，并使 <tt>StringBuffer</tt> 在长度上增加该参数的长度。如果 <tt>sb</tt> 为 <tt>null</tt>，则将 4 个 <tt>&quot;null&quot;</tt> 字符追加到此 <tt>StringBuffer</tt> 中。
 <p>
在执行 <tt>append</tt> 方法前，让 <tt>StringBuffer</tt> 中包含的原有字符序列的长度为 <i>n</i>。如果 <i>k</i> 小于 <i>n</i>，则新字符序列中索引 <i>k</i> 处的字符等于原有字符序列中索引 <i>k</i> 处的字符；否则它等于参数 <code>sb</code> 中索引 <i>k-n</i> 处的字符。
 <p>
该方法在 <code>this</code>（目标）对象上实现同步，但不在源上（<code>sb</code>）实现同步。
<P>
<DD><DL>
</DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>sb</CODE> - 要追加的 <tt>StringBuffer</tt>。
<DT><B>返回：</B><DD>该对象的一个引用。<DT><B>从以下版本开始：</B></DT>
  <DD>1.4</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="append(java.lang.CharSequence)"><!-- --></A><H3>
append</H3>
<PRE>
public <A HREF="StringBuffer.html" title="java.lang 中的类">StringBuffer</A> <B>append</B>(<A HREF="CharSequence.html" title="java.lang 中的接口">CharSequence</A>&nbsp;s)</PRE>
<DL>
<DD>将指定的 <code>CharSequence</code> 追加到该序列。
 <p>
按顺序将 <code>CharSequence</code> 参数中的字符追加到该序列中，使该序列增加该参数的长度。

<p>该方法的结果与调用 this.append(s, 0, s.length()) 完全相同；
 
<p>该方法在 this（目标）对象上实现同步，但不在源上（<code>s</code>）实现同步。

<p>如果 <code>s</code> 为 <code>null</code>，则追加 4 个 <code>&quot;null&quot;</code> 字符。
<P>
<DD><DL>
<DT><B>指定者：</B><DD>接口 <CODE><A HREF="Appendable.html" title="java.lang 中的接口">Appendable</A></CODE> 中的 <CODE><A HREF="Appendable.html#append(java.lang.CharSequence)">append</A></CODE></DL>
</DD>
<DD><DL>
<DT><B>参数：</B><DD><CODE>s</CODE> - 要追加的 <code>CharSequence</code>。
<DT><B>返回：</B><DD>此对象的一个引用。<DT><B>从以下版本开始：</B></DT>
  <DD>1.5</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="append(java.lang.CharSequence, int, int)"><!-- --></A><H3>
append</H3>
<PRE>
public <A HREF="StringBuffer.html" title="java.lang 中的类">StringBuffer</A> <B>append</B>(<A HREF="CharSequence.html" title="java.lang 中的接口">CharSequence</A>&nbsp;s,
                           int&nbsp;start,
                           int&nbsp;end)</PRE>
<DL>
<DD>Appends a subsequence of the specified <code>CharSequence</code> to this
 sequence.
 <p>
 Characters of the argument <code>s</code>, starting at