java io学习（十八） CharArrayWriter（字符数组输出流）

java io学习（十八） CharArrayWriter（字符数组输出流）2014-08-12

CharArrayWriter 介绍

CharArrayReader 用于写入数据符，它继承于Writer。操作的数据是以字符为单位！

CharArrayWriter 函数列表

CharArrayWriter（）CharArrayWriter（int initialSize） CharArrayWriter append（CharSequence csq, int start, int end）CharArrayWriter append（char c）CharArrayWriter append（CharSequence csq）void close（）void flush（）void reset（）int size（）char[] toCharArray（）String toString（）void write（char[] buffer, int offset, int len）void write（int oneChar）void write（String str, int offset, int count）void writeTo（Writer out）

Writer和CharArrayWriter源码分析

Writer是CharArrayWriter的父类，我们先看看Writer的源码，然后再学CharArrayWriter的源码。

1. Writer源码分析（基于jdk1.7.40）

package java.io; public abstract class Writer implements Appendable, Closeable, Flushable { private char[] writeBuffer; private final int writeBufferSize = 1024; protected Object lock; protected Writer（） {this.lock = this;} protected Writer（Object lock） {if （lock == null） {throw new NullPointerException（）;}this.lock = lock;} public void write（int c） throws IOException {synchronized （lock） {if （writeBuffer == null）{writeBuffer = new char[writeBufferSize];}writeBuffer[0] = （char） c;write（writeBuffer, 0, 1）;}} public void write（char cbuf[]） throws IOException {write（cbuf, 0, cbuf.length）;} abstract public void write（char cbuf[], int off, int len） throws IOException; public void write（String str） throws IOException {write（str, 0, str.length（））;} public void write（String str, int off, int len） throws IOException {synchronized （lock） {char cbuf[];if （len <= writeBufferSize） {if （writeBuffer == null） {writeBuffer = new char[writeBufferSize];}cbuf = writeBuffer;} else {// Don"t permanently allocate very large buffers.cbuf = new char[len];}str.getChars（off, （off + len）, cbuf, 0）;write（cbuf, 0, len）;}} public Writer append（CharSequence csq） throws IOException {if （csq == null）write（"null"）;elsewrite（csq.toString（））;return this;} public Writer append（CharSequence csq, int start, int end） throws IOException {CharSequence cs = （csq == null ？ "null" : csq）;write（cs.subSequence（start, end）.toString（））;return this;} public Writer append（char c） throws IOException {write（c）;return this;} abstract public void flush（） throws IOException; abstract public void close（） throws IOException;}