CharArrayWriter

CharArrayWriter is an output stream that uses an array as the destination. CharArrayWriter has two constructors, shown here:

CharArrayWriter( ): a buffer with a default size is created.
CharArrayWriter(int numChars): a buffer with a numChars size is created.

The buffer size will be increased automatically, if needed.

CharArrayWriter append(char c): Appends the specified character to this writer.
CharArrayWriter append(CharSequence csq): Appends the specified character sequence to this writer.
CharArrayWriter append(CharSequence csq, int start, int end): Appends a subsequence of the specified character sequence to this writer.
void close(): Close the stream.
void flush(): Flush the stream.
void reset(): Resets the buffer so that you can use it again without throwing away the already allocated buffer.
int size(): Returns the current size of the buffer.
char[] toCharArray(): Returns a copy of the input data.
String toString(): Converts input data to a string.
void write(char[] c, int off, int len): Writes characters to the buffer.
void write(int c): Writes a character to the buffer.
void write(String str, int off, int len): Write a portion of a string to the buffer.
void writeTo(Writer out): Writes the contents of the buffer to another character stream.

Revised from Open JDK source code


import java.io.CharArrayWriter;
import java.io.IOException;

public class Main {
  public static void main(String args[]) throws IOException {
    CharArrayWriter outStream = new CharArrayWriter();
    outStream.write('a');
    outStream.write('b');
    outStream.write('c');
    outStream.write('d');
    outStream.write('e');
    outStream.write('f');
    outStream.write("java2s.com");
    
    System.out.println("outstream: " + outStream);
    System.out.println("size: " + outStream.size());

  }
}

The output:


outstream: abcdefjava2s.com
size: 16

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