Module java.base
Package java.io

Class PrintStream

  • All Implemented Interfaces:
    Closeable,Flushable,Appendable,AutoCloseable
    Direct Known Subclasses:
    LogStream
    public classPrintStreamextendsFilterOutputStreamimplementsAppendable,Closeable
    APrintStream adds functionality to another output stream, namely the ability to print representations of various data values conveniently. Two other features are provided as well. Unlike other output streams, aPrintStream never throws anIOException; instead, exceptional situations merely set an internal flag that can be tested via thecheckError method. Optionally, aPrintStream can be created so as to flush automatically; this means that theflush method is automatically invoked after a byte array is written, one of theprintln methods is invoked, or a newline character or byte ('\n') is written.

    All characters printed by aPrintStream are converted into bytes using the given encoding or charset, or platform's default character encoding if not specified. ThePrintWriter class should be used in situations that require writing characters rather than bytes.

    This class always replaces malformed and unmappable character sequences with the charset's default replacement string. TheCharsetEncoder class should be used when more control over the encoding process is required.

    Since:
    1.0

    • Constructor Summary

      Constructors 
      ConstructorDescription
      PrintStream​(File file)
      Creates a new print stream, without automatic line flushing, with the specified file.
      PrintStream​(File file,String csn)
      Creates a new print stream, without automatic line flushing, with the specified file and charset.
      PrintStream​(File file,Charset charset)
      Creates a new print stream, without automatic line flushing, with the specified file and charset.
      PrintStream​(OutputStream out)
      Creates a new print stream.
      PrintStream​(OutputStream out, boolean autoFlush)
      Creates a new print stream.
      PrintStream​(OutputStream out, boolean autoFlush,String encoding)
      Creates a new print stream.
      PrintStream​(OutputStream out, boolean autoFlush,Charset charset)
      Creates a new print stream, with the specified OutputStream, automatic line flushing and charset.
      PrintStream​(String fileName)
      Creates a new print stream, without automatic line flushing, with the specified file name.
      PrintStream​(String fileName,String csn)
      Creates a new print stream, without automatic line flushing, with the specified file name and charset.
      PrintStream​(String fileName,Charset charset)
      Creates a new print stream, without automatic line flushing, with the specified file name and charset.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and TypeMethodDescription
      PrintStreamappend​(char c)
      Appends the specified character to this output stream.
      PrintStreamappend​(CharSequence csq)
      Appends the specified character sequence to this output stream.
      PrintStreamappend​(CharSequence csq, int start, int end)
      Appends a subsequence of the specified character sequence to this output stream.
      booleancheckError()
      Flushes the stream and checks its error state.
      protected voidclearError()
      Clears the internal error state of this stream.
      voidclose()
      Closes the stream.
      voidflush()
      Flushes the stream.
      PrintStreamformat​(String format,Object... args)
      Writes a formatted string to this output stream using the specified format string and arguments.
      PrintStreamformat​(Locale l,String format,Object... args)
      Writes a formatted string to this output stream using the specified format string and arguments.
      voidprint​(boolean b)
      Prints a boolean value.
      voidprint​(char c)
      Prints a character.
      voidprint​(char[] s)
      Prints an array of characters.
      voidprint​(double d)
      Prints a double-precision floating-point number.
      voidprint​(float f)
      Prints a floating-point number.
      voidprint​(int i)
      Prints an integer.
      voidprint​(long l)
      Prints a long integer.
      voidprint​(Object obj)
      Prints an object.
      voidprint​(String s)
      Prints a string.
      PrintStreamprintf​(String format,Object... args)
      A convenience method to write a formatted string to this output stream using the specified format string and arguments.
      PrintStreamprintf​(Locale l,String format,Object... args)
      A convenience method to write a formatted string to this output stream using the specified format string and arguments.
      voidprintln()
      Terminates the current line by writing the line separator string.
      voidprintln​(boolean x)
      Prints a boolean and then terminate the line.
      voidprintln​(char x)
      Prints a character and then terminate the line.
      voidprintln​(char[] x)
      Prints an array of characters and then terminate the line.
      voidprintln​(double x)
      Prints a double and then terminate the line.
      voidprintln​(float x)
      Prints a float and then terminate the line.
      voidprintln​(int x)
      Prints an integer and then terminate the line.
      voidprintln​(long x)
      Prints a long and then terminate the line.
      voidprintln​(Object x)
      Prints an Object and then terminate the line.
      voidprintln​(String x)
      Prints a String and then terminate the line.
      protected voidsetError()
      Sets the error state of the stream totrue.
      voidwrite​(byte[] buf, int off, int len)
      Writeslen bytes from the specified byte array starting at offsetoff to this stream.
      voidwrite​(int b)
      Writes the specified byte to this stream.

    • Constructor Detail

      • PrintStream

        public PrintStream​(OutputStream out)
        Creates a new print stream. This stream will not flush automatically.
        Parameters:
        out - The output stream to which values and objects will be printed
        See Also:
        PrintWriter(java.io.OutputStream)

      • PrintStream

        public PrintStream​(OutputStream out,                   boolean autoFlush)
        Creates a new print stream.
        Parameters:
        out - The output stream to which values and objects will be printed
        autoFlush - A boolean; if true, the output buffer will be flushed whenever a byte array is written, one of theprintln methods is invoked, or a newline character or byte ('\n') is written
        See Also:
        PrintWriter(java.io.OutputStream, boolean)

      • PrintStream

        public PrintStream​(OutputStream out,                   boolean autoFlush,String encoding)            throwsUnsupportedEncodingException
        Creates a new print stream.
        Parameters:
        out - The output stream to which values and objects will be printed
        autoFlush - A boolean; if true, the output buffer will be flushed whenever a byte array is written, one of theprintln methods is invoked, or a newline character or byte ('\n') is written
        encoding - The name of a supported character encoding
        Throws:
        UnsupportedEncodingException - If the named encoding is not supported
        Since:
        1.4

      • PrintStream

        public PrintStream​(OutputStream out,                   boolean autoFlush,Charset charset)
        Creates a new print stream, with the specified OutputStream, automatic line flushing and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using the provided charset.
        Parameters:
        out - The output stream to which values and objects will be printed
        autoFlush - A boolean; if true, the output buffer will be flushed whenever a byte array is written, one of theprintln methods is invoked, or a newline character or byte ('\n') is written
        charset - Acharset
        Since:
        10

      • PrintStream

        public PrintStream​(String fileName)            throwsFileNotFoundException
        Creates a new print stream, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using thedefault charset for this instance of the Java virtual machine.
        Parameters:
        fileName - The name of the file to use as the destination of this print stream. If the file exists, then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
        Throws:
        FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
        SecurityException - If a security manager is present andcheckWrite(fileName) denies write access to the file
        Since:
        1.5

      • PrintStream

        public PrintStream​(String fileName,String csn)            throwsFileNotFoundException,UnsupportedEncodingException
        Creates a new print stream, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using the provided charset.
        Parameters:
        fileName - The name of the file to use as the destination of this print stream. If the file exists, then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
        csn - The name of a supportedcharset
        Throws:
        FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
        SecurityException - If a security manager is present andcheckWrite(fileName) denies write access to the file
        UnsupportedEncodingException - If the named charset is not supported
        Since:
        1.5

      • PrintStream

        public PrintStream​(String fileName,Charset charset)            throwsIOException
        Creates a new print stream, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using the provided charset.
        Parameters:
        fileName - The name of the file to use as the destination of this print stream. If the file exists, then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
        charset - Acharset
        Throws:
        IOException - if an I/O error occurs while opening or creating the file
        SecurityException - If a security manager is present andcheckWrite(fileName) denies write access to the file
        Since:
        10

      • PrintStream

        public PrintStream​(File file)            throwsFileNotFoundException
        Creates a new print stream, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using thedefault charset for this instance of the Java virtual machine.
        Parameters:
        file - The file to use as the destination of this print stream. If the file exists, then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
        Throws:
        FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
        SecurityException - If a security manager is present andcheckWrite(file.getPath()) denies write access to the file
        Since:
        1.5

      • PrintStream

        public PrintStream​(File file,String csn)            throwsFileNotFoundException,UnsupportedEncodingException
        Creates a new print stream, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using the provided charset.
        Parameters:
        file - The file to use as the destination of this print stream. If the file exists, then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
        csn - The name of a supportedcharset
        Throws:
        FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
        SecurityException - If a security manager is present andcheckWrite(file.getPath()) denies write access to the file
        UnsupportedEncodingException - If the named charset is not supported
        Since:
        1.5

      • PrintStream

        public PrintStream​(File file,Charset charset)            throwsIOException
        Creates a new print stream, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using the provided charset.
        Parameters:
        file - The file to use as the destination of this print stream. If the file exists, then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
        charset - Acharset
        Throws:
        IOException - if an I/O error occurs while opening or creating the file
        SecurityException - If a security manager is present andcheckWrite(file.getPath()) denies write access to the file
        Since:
        10

    • Method Detail

      • checkError

        public boolean checkError()
        Flushes the stream and checks its error state. The internal error state is set totrue when the underlying output stream throws anIOException other thanInterruptedIOException, and when thesetError method is invoked. If an operation on the underlying output stream throws anInterruptedIOException, then thePrintStream converts the exception back into an interrupt by doing:
             Thread.currentThread().interrupt();
        or the equivalent.
        Returns:
        true if and only if this stream has encountered anIOException other thanInterruptedIOException, or thesetError method has been invoked

      • setError

        protected void setError()
        Sets the error state of the stream totrue.

        This method will cause subsequent invocations ofcheckError() to returntrue untilclearError() is invoked.

        Since:
        1.1

      • clearError

        protected void clearError()
        Clears the internal error state of this stream.

        This method will cause subsequent invocations ofcheckError() to returnfalse until another write operation fails and invokessetError().

        Since:
        1.6

      • write

        public void write​(int b)
        Writes the specified byte to this stream. If the byte is a newline and automatic flushing is enabled then theflush method will be invoked.

        Note that the byte is written as given; to write a character that will be translated according to the platform's default character encoding, use theprint(char) orprintln(char) methods.

        Overrides:
        write in class FilterOutputStream
        Parameters:
        b - The byte to be written
        See Also:
        print(char),println(char)

      • write

        public void write​(byte[] buf,                  int off,                  int len)
        Writeslen bytes from the specified byte array starting at offsetoff to this stream. If automatic flushing is enabled then theflush method will be invoked.

        Note that the bytes will be written as given; to write characters that will be translated according to the platform's default character encoding, use theprint(char) orprintln(char) methods.

        Overrides:
        write in class FilterOutputStream
        Parameters:
        buf - A byte array
        off - Offset from which to start taking bytes
        len - Number of bytes to write
        See Also:
        FilterOutputStream.write(int)

      • print

        public void print​(boolean b)
        Prints a boolean value. The string produced byString.valueOf(boolean) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        b - Theboolean to be printed

      • print

        public void print​(char c)
        Prints a character. The character is translated into one or more bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        c - Thechar to be printed

      • print

        public void print​(int i)
        Prints an integer. The string produced byString.valueOf(int) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        i - Theint to be printed
        See Also:
        Integer.toString(int)

      • print

        public void print​(long l)
        Prints a long integer. The string produced byString.valueOf(long) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        l - Thelong to be printed
        See Also:
        Long.toString(long)

      • print

        public void print​(float f)
        Prints a floating-point number. The string produced byString.valueOf(float) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        f - Thefloat to be printed
        See Also:
        Float.toString(float)

      • print

        public void print​(double d)
        Prints a double-precision floating-point number. The string produced byString.valueOf(double) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        d - Thedouble to be printed
        See Also:
        Double.toString(double)

      • print

        public void print​(char[] s)
        Prints an array of characters. The characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        s - The array of chars to be printed
        Throws:
        NullPointerException - Ifs isnull

      • print

        public void print​(String s)
        Prints a string. If the argument isnull then the string"null" is printed. Otherwise, the string's characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        s - TheString to be printed

      • print

        public void print​(Object obj)
        Prints an object. The string produced by theString.valueOf(Object) method is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int) method.
        Parameters:
        obj - TheObject to be printed
        See Also:
        Object.toString()

      • println

        public void println()
        Terminates the current line by writing the line separator string. The line separator string is defined by the system propertyline.separator, and is not necessarily a single newline character ('\n').

      • println

        public void println​(boolean x)
        Prints a boolean and then terminate the line. This method behaves as though it invokesprint(boolean) and thenprintln().
        Parameters:
        x - Theboolean to be printed

      • println

        public void println​(char x)
        Prints a character and then terminate the line. This method behaves as though it invokesprint(char) and thenprintln().
        Parameters:
        x - Thechar to be printed.

      • println

        public void println​(int x)
        Prints an integer and then terminate the line. This method behaves as though it invokesprint(int) and thenprintln().
        Parameters:
        x - Theint to be printed.

      • println

        public void println​(long x)
        Prints a long and then terminate the line. This method behaves as though it invokesprint(long) and thenprintln().
        Parameters:
        x - a Thelong to be printed.

      • println

        public void println​(float x)
        Prints a float and then terminate the line. This method behaves as though it invokesprint(float) and thenprintln().
        Parameters:
        x - Thefloat to be printed.

      • println

        public void println​(double x)
        Prints a double and then terminate the line. This method behaves as though it invokesprint(double) and thenprintln().
        Parameters:
        x - Thedouble to be printed.

      • println

        public void println​(char[] x)
        Prints an array of characters and then terminate the line. This method behaves as though it invokesprint(char[]) and thenprintln().
        Parameters:
        x - an array of chars to print.

      • println

        public void println​(String x)
        Prints a String and then terminate the line. This method behaves as though it invokesprint(String) and thenprintln().
        Parameters:
        x - TheString to be printed.

      • println

        public void println​(Object x)
        Prints an Object and then terminate the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokesprint(String) and thenprintln().
        Parameters:
        x - TheObject to be printed.

      • printf

        public PrintStream printf​(String format,Object... args)
        A convenience method to write a formatted string to this output stream using the specified format string and arguments.

        An invocation of this method of the formout.printf(format, args) behaves in exactly the same way as the invocation

             out.format(format, args)

        Parameters:
        format - A format string as described inFormat string syntax
        args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined byThe Java™ Virtual Machine Specification. The behaviour on anull argument depends on theconversion.
        Returns:
        This output stream
        Throws:
        IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see theDetails section of the formatter class specification.
        NullPointerException - If theformat isnull
        Since:
        1.5

      • printf

        public PrintStream printf​(Locale l,String format,Object... args)
        A convenience method to write a formatted string to this output stream using the specified format string and arguments.

        An invocation of this method of the formout.printf(l, format, args) behaves in exactly the same way as the invocation

             out.format(l, format, args)

        Parameters:
        l - Thelocale to apply during formatting. Ifl isnull then no localization is applied.
        format - A format string as described inFormat string syntax
        args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined byThe Java™ Virtual Machine Specification. The behaviour on anull argument depends on theconversion.
        Returns:
        This output stream
        Throws:
        IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see theDetails section of the formatter class specification.
        NullPointerException - If theformat isnull
        Since:
        1.5

      • format

        public PrintStream format​(String format,Object... args)
        Writes a formatted string to this output stream using the specified format string and arguments.

        The locale always used is the one returned byLocale.getDefault(Locale.Category) withFORMAT category specified, regardless of any previous invocations of other formatting methods on this object.

        Parameters:
        format - A format string as described inFormat string syntax
        args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined byThe Java™ Virtual Machine Specification. The behaviour on anull argument depends on theconversion.
        Returns:
        This output stream
        Throws:
        IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see theDetails section of the formatter class specification.
        NullPointerException - If theformat isnull
        Since:
        1.5

      • format

        public PrintStream format​(Locale l,String format,Object... args)
        Writes a formatted string to this output stream using the specified format string and arguments.
        Parameters:
        l - Thelocale to apply during formatting. Ifl isnull then no localization is applied.
        format - A format string as described inFormat string syntax
        args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined byThe Java™ Virtual Machine Specification. The behaviour on anull argument depends on theconversion.
        Returns:
        This output stream
        Throws:
        IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see theDetails section of the formatter class specification.
        NullPointerException - If theformat isnull
        Since:
        1.5

      • append

        public PrintStream append​(CharSequence csq)
        Appends the specified character sequence to this output stream.

        An invocation of this method of the formout.append(csq) behaves in exactly the same way as the invocation

             out.print(csq.toString())

        Depending on the specification oftoString for the character sequencecsq, the entire sequence may not be appended. For instance, invoking thentoString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.

        Specified by:
        append in interface Appendable
        Parameters:
        csq - The character sequence to append. Ifcsq isnull, then the four characters"null" are appended to this output stream.
        Returns:
        This output stream
        Since:
        1.5

      • append

        public PrintStream append​(CharSequence csq,                          int start,                          int end)
        Appends a subsequence of the specified character sequence to this output stream.

        An invocation of this method of the formout.append(csq, start, end) whencsq is notnull, behaves in exactly the same way as the invocation

             out.print(csq.subSequence(start, end).toString())

        Specified by:
        append in interface Appendable
        Parameters:
        csq - The character sequence from which a subsequence will be appended. Ifcsq isnull, then characters will be appended as ifcsq contained the four characters"null".
        start - The index of the first character in the subsequence
        end - The index of the character following the last character in the subsequence
        Returns:
        This output stream
        Throws:
        IndexOutOfBoundsException - Ifstart orend are negative,start is greater thanend, orend is greater thancsq.length()
        Since:
        1.5

      • append

        public PrintStream append​(char c)
        Appends the specified character to this output stream.

        An invocation of this method of the formout.append(c) behaves in exactly the same way as the invocation

             out.print(c)

        Specified by:
        append in interface Appendable
        Parameters:
        c - The 16-bit character to append
        Returns:
        This output stream
        Since:
        1.5