/**
* Provides an output stream for sending binary data to the
* client. A <code>ServletOutputStream</code> object is normally retrieved
* via the {@link ServletResponse#getOutputStream} method.
*
* <p>This is an abstract class that the servlet container implements.
* Subclasses of this class
* must implement the <code>java.io.OutputStream.write(int)</code>
* method.
*
*
* @author Various
* @version $Version$
*
* @see ServletResponse
*
*/
//提供一个输出流来发送二进制数据给客户端，Servlet容器会实现这个类，这个类的子类一定要实现java.io.OutputStream.write(int)方法
public abstract class ServletOutputStream extends OutputStream {
private static final String LSTRING_FILE = "javax.servlet.LocalStrings";
private static ResourceBundle lStrings =
ResourceBundle.getBundle(LSTRING_FILE);
/**
* Does nothing, because this is an abstract class.
*/
//抽象类的构造函数
protected ServletOutputStream() { }
/**
* Writes a <code>String</code> to the client,
* without a carriage return-line feed (CRLF)
* character at the end.
* @param s the <code>String</code> to send to the client
* @exception IOException if an input or output exception occurred
*/
//向客户端写string
public void print(String s) throws IOException {
if (s==null) s="null";
int len = s.length();
for (int i = 0; i < len; i++) {
char c = s.charAt (i);
// XXX NOTE: This is clearly incorrect for many strings,
// but is the only consistent approach within the current
// servlet framework. It must suffice until servlet output
// streams properly encode their output.
//
if ((c & 0xff00) != 0) { // high order byte must be zero
String errMsg = lStrings.getString("err.not_iso8859_1");
Object[] errArgs = new Object[1];
errArgs[0] = new Character(c);
errMsg = MessageFormat.format(errMsg, errArgs);
throw new CharConversionException(errMsg);
}
write (c);
}
}
/**
* Writes a <code>boolean</code> value to the client,
* with no carriage return-line feed (CRLF)
* character at the end.
* @param b the <code>boolean</code> value
* to send to the client
* @exception IOException if an input or output exception occurred
*/
//向客户端写boolean
public void print(boolean b) throws IOException {
String msg;
if (b) {
msg = lStrings.getString("value.true");
} else {
msg = lStrings.getString("value.false");
}
print(msg);
}
/**
* Writes a character to the client,
* with no carriage return-line feed (CRLF)
* at the end.
* @param c the character to send to the client
* @exception IOException if an input or output exception occurred
*/
//向客户端写字符
public void print(char c) throws IOException {
print(String.valueOf(c));
}
/**
* Writes an int to the client,
* with no carriage return-line feed (CRLF)
* at the end.
* @param i the int to send to the client
* @exception IOException if an input or output exception occurred
*/
//写int
public void print(int i) throws IOException {
print(String.valueOf(i));
}
/**
* Writes a <code>long</code> value to the client,
* with no carriage return-line feed (CRLF) at the end.
* @param l the <code>long</code> value
* to send to the client
* @exception IOException if an input or output exception
* occurred
*/
//写long
public void print(long l) throws IOException {
print(String.valueOf(l));
}
/**
* Writes a <code>float</code> value to the client,
* with no carriage return-line feed (CRLF) at the end.
* @param f the <code>float</code> value
* to send to the client
* @exception IOException if an input or output exception occurred
*/
//写float
public void print(float f) throws IOException {
print(String.valueOf(f));
}
/**
* Writes a <code>double</code> value to the client,
* with no carriage return-line feed (CRLF) at the end.
* @param d the <code>double</code> value
* to send to the client
* @exception IOException if an input or output exception occurred
*/
//写double
public void print(double d) throws IOException {
print(String.valueOf(d));
}
/**
* Writes a carriage return-line feed (CRLF)
* to the client.
* @exception IOException if an input or output exception occurred
*/
//换行
public void println() throws IOException {
print("\r\n");
}
/**
* Writes a <code>String</code> to the client,
* followed by a carriage return-line feed (CRLF).
* @param s the <code>String</code> to write to the client
* @exception IOException if an input or output exception occurred
*/
//写string并回车
public void println(String s) throws IOException {
print(s);
println();
}
/**
* Writes a <code>boolean</code> value to the client,
* followed by a
* carriage return-line feed (CRLF).
* @param b the <code>boolean</code> value
* to write to the client
* @exception IOException if an input or output exception occurred
*/
//boolean 回车
public void println(boolean b) throws IOException {
print(b);
println();
}
/**
* Writes a character to the client, followed by a carriage
* return-line feed (CRLF).
* @param c the character to write to the client
* @exception IOException if an input or output exception occurred
*/
//字符 回车
public void println(char c) throws IOException {
print(c);
println();
}
/**
* Writes an int to the client, followed by a
* carriage return-line feed (CRLF) character.
* @param i the int to write to the client
* @exception IOException if an input or output exception occurred
*/
//int 回车
public void println(int i) throws IOException {
print(i);
println();
}
/**
* Writes a <code>long</code> value to the client, followed by a
* carriage return-line feed (CRLF).
* @param l the <code>long</code> value to write to the client
* @exception IOException if an input or output exception occurred
*/
//long 回车
public void println(long l) throws IOException {
print(l);
println();
}
/**
* Writes a <code>float</code> value to the client,
* followed by a carriage return-line feed (CRLF).
* @param f the <code>float</code> value to write to the client
* @exception IOException if an input or output exception occurred
*/
//float 回车
public void println(float f) throws IOException {
print(f);
println();
}
/**
* Writes a <code>double</code> value to the client,
* followed by a carriage return-line feed (CRLF).
* @param d the <code>double</code> value to write to the client
* @exception IOException if an input or output exception occurred
*/
//double 回车
public void println(double d) throws IOException {
print(d);
println();
}
}