Most visited

Recently visited

Results for

Added in API level 1

PrintWriter

public class PrintWriter
extends Writer

java.lang.Object
↳	java.io.Writer
	↳	java.io.PrintWriter

将对象的格式化表示形式打印到文本输出流。这个类实现所有中找到的print种方法PrintStream 。它不包含写入原始字节的方法，程序应使用未编码的字节流。

与PrintStream类不同，如果启用了自动刷新功能，则只有在调用println,printf或format方法之一时才会完成此操作 ，而不是每当恰好输出换行符时。这些方法使用平台自己的行分隔符而不是换行符。

该类中的方法不会抛出I / O异常，尽管它的一些构造函数可能会这样。客户可以通过调用checkError()来查询是否发生了错误。

Summary

Fields
`protected Writer`	`out` 这个 `PrintWriter`的底层字符输出流。

Inherited fields

From class java.io.Writer

Public constructors
`PrintWriter(Writer out)` 创建一个新的PrintWriter，不会自动行刷新。
`PrintWriter(Writer out, boolean autoFlush)` 创建一个新的PrintWriter。
`PrintWriter(OutputStream out)` 从现有的OutputStream中创建一个新的PrintWriter，不会自动清除行。
`PrintWriter(OutputStream out, boolean autoFlush)` 从现有的OutputStream创建一个新的PrintWriter。
`PrintWriter(String fileName)` 用指定的文件名创建一个新的PrintWriter，不用自动换行。
`PrintWriter(String fileName, String csn)` 用指定的文件名和字符集创建一个新的PrintWriter，不用自动换行。
`PrintWriter(File file)` 用指定的文件创建一个新的PrintWriter，不用自动换行。
`PrintWriter(File file, String csn)` 用指定的文件和字符集创建一个新的PrintWriter，不用自动换行。

Public methods
`PrintWriter`	`append(char c)` 将指定的字符附加到此作者。
`PrintWriter`	`append(CharSequence csq, int start, int end)` 将指定字符序列的子序列附加到此作者。
`PrintWriter`	`append(CharSequence csq)` 将指定的字符序列追加到此作者。
`boolean`	`checkError()` 刷新流如果没有关闭并检查其错误状态。
`void`	`close()` 关闭流并释放与其关联的所有系统资源。
`void`	`flush()` 刷新流。
`PrintWriter`	`format(Locale l, String format, Object... args)` 使用指定的格式字符串和参数将格式化的字符串写入此写入器。
`PrintWriter`	`format(String format, Object... args)` 使用指定的格式字符串和参数将格式化的字符串写入此写入器。
`void`	`print(int i)` 打印一个整数。
`void`	`print(double d)` 打印一个双精度浮点数。
`void`	`print(boolean b)` 打印一个布尔值。
`void`	`print(char c)` 打印一个角色。
`void`	`print(long l)` 打印一个长整数。
`void`	`print(float f)` 打印一个浮点数。
`void`	`print(String s)` 打印一个字符串。
`void`	`print(Object obj)` 打印一个对象。
`void`	`print(char[] s)` 打印一组字符。
`PrintWriter`	`printf(String format, Object... args)` 使用指定的格式字符串和参数将格式化的字符串写入此写入器的便捷方法。
`PrintWriter`	`printf(Locale l, String format, Object... args)` 使用指定的格式字符串和参数将格式化的字符串写入此写入器的便捷方法。
`void`	`println(Object x)` 打印一个对象，然后终止该行。
`void`	`println(char x)` 打印一个字符，然后终止该行。
`void`	`println(boolean x)` 打印一个布尔值，然后终止该行。
`void`	`println(long x)` 打印一个长整数，然后终止该行。
`void`	`println()` 通过写入行分隔符字符串来终止当前行。
`void`	`println(int x)` 打印一个整数，然后终止该行。
`void`	`println(String x)` 打印一个字符串，然后终止该行。
`void`	`println(char[] x)` 打印一组字符，然后终止该行。
`void`	`println(float x)` 打印一个浮点数，然后终止该行。
`void`	`println(double x)` 打印一个双精度浮点数，然后终止该行。
`void`	`write(int c)` 写一个字符。
`void`	`write(char[] buf, int off, int len)` 写入一组字符的部分。
`void`	`write(String s)` 写入一个字符串。
`void`	`write(String s, int off, int len)` 写入一部分字符串。
`void`	`write(char[] buf)` 写入一个字符数组。

Protected methods
`void`	`clearError()` 清除此流的错误状态。
`void`	`setError()` 表示发生错误。

Inherited methods

From class java.io.Writer

From class java.lang.Object

From interface java.lang.Appendable

From interface java.io.Closeable

From interface java.io.Flushable

From interface java.lang.AutoCloseable

Fields

out

Added in API level 1

Writer out

这个 PrintWriter的底层字符输出流。

Public constructors

PrintWriter

Added in API level 1

PrintWriter (Writer out)

创建一个新的PrintWriter，不会自动行刷新。

Parameters
`out`	`Writer`: A character-output stream

PrintWriter

Added in API level 1

PrintWriter (Writer out, 
                boolean autoFlush)

创建一个新的PrintWriter。

Parameters
`out`	`Writer`: A character-output stream
`autoFlush`	`boolean`: A boolean; if true, the `println`, `printf`, or `format` methods will flush the output buffer

PrintWriter

Added in API level 1

PrintWriter (OutputStream out)

从现有的OutputStream中创建一个新的PrintWriter，不会自动清除行。这个便捷的构造函数创建必要的中间OutputStreamWriter，它将使用默认字符编码将字符转换为字节。

Parameters
`out`	`OutputStream`: An output stream

也可以看看：

OutputStreamWriter(java.io.OutputStream)

PrintWriter

Added in API level 1

PrintWriter (OutputStream out, 
                boolean autoFlush)

从现有的OutputStream创建一个新的PrintWriter。这个便捷的构造函数创建必要的中间OutputStreamWriter，它将使用默认字符编码将字符转换为字节。

Parameters
`out`	`OutputStream`: An output stream
`autoFlush`	`boolean`: A boolean; if true, the `println`, `printf`, or `format` methods will flush the output buffer

也可以看看：

OutputStreamWriter(java.io.OutputStream)

PrintWriter

Added in API level 1

PrintWriter (String fileName)

用指定的文件名创建一个新的PrintWriter，不用自动换行。这个便利的构造函数创建了必要的中间值OutputStreamWriter ，它将使用default charset为Java虚拟机的此实例编码字符。

Parameters
`fileName`	`String`: The name of the file to use as the destination of this writer. 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 string 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 and `checkWrite(fileName)` denies write access to the file

PrintWriter

Added in API level 1

PrintWriter (String fileName, 
                String csn)

用指定的文件名和字符集创建一个新的PrintWriter，不用自动换行。这个便捷的构造函数创建了必要的中间值OutputStreamWriter ，它将使用提供的字符集对字符进行编码。

Parameters
`fileName`	`String`: The name of the file to use as the destination of this writer. 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`	`String`: The name of a supported charset

Throws
`FileNotFoundException`	If the given string 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 and `checkWrite(fileName)` denies write access to the file
`UnsupportedEncodingException`	If the named charset is not supported

PrintWriter

Added in API level 1

PrintWriter (File file)

用指定的文件创建一个新的PrintWriter，不用自动换行。这个便捷的构造函数创建了必要的中间值OutputStreamWriter ，它将使用default charset为Java虚拟机的此实例编码字符。

Parameters
`file`	`File`: The file to use as the destination of this writer. 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 and `checkWrite(file.getPath())` denies write access to the file

PrintWriter

Added in API level 1

PrintWriter (File file, 
                String csn)

用指定的文件和字符集创建一个新的PrintWriter，不用自动换行。这个便利的构造函数创建了必要的中间值OutputStreamWriter ，它将使用提供的字符集对字符进行编码。

Parameters
`file`	`File`: The file to use as the destination of this writer. 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`	`String`: The name of a supported charset

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 and `checkWrite(file.getPath())` denies write access to the file
`UnsupportedEncodingException`	If the named charset is not supported

Public methods

append

Added in API level 1

PrintWriter append (char c)

将指定的字符附加到此作者。

表单 out.append(c)的此方法的调用的行为与调用完全相同

     out.write(c)

Parameters
`c`	`char`: The 16-bit character to append

Returns
`PrintWriter`	This writer

append

Added in API level 1

PrintWriter append (CharSequence csq, 
                int start, 
                int end)

将指定字符序列的子序列附加到此作者。

形式的这种方法的调用时 out.append(csq, start, end) csq不是 null，行为以完全相同的方式调用

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

Parameters
`csq`	`CharSequence`: The character sequence from which a subsequence will be appended. If `csq` is `null`, then characters will be appended as if `csq` contained the four characters `"null"`.
`start`	`int`: The index of the first character in the subsequence
`end`	`int`: The index of the character following the last character in the subsequence

Returns
`PrintWriter`	This writer

Throws
`IndexOutOfBoundsException`	If `start` or `end` are negative, `start` is greater than `end`, or `end` is greater than `csq.length()`

append

Added in API level 1

PrintWriter append (CharSequence csq)

将指定的字符序列追加到此作者。

调用表单 out.append(csq)的此方法的行为与调用完全相同

     out.write(csq.toString())

取决于toString字符序列csq本说明书中，整个序列可以不追加。例如，调用字符缓冲区的toString方法将返回一个子序列，其内容取决于缓冲区的位置和限制。

Parameters
`csq`	`CharSequence`: The character sequence to append. If `csq` is `null`, then the four characters `"null"` are appended to this writer.

Returns
`PrintWriter`	This writer

checkError

Added in API level 1

boolean checkError ()

刷新流如果没有关闭并检查其错误状态。

Returns
`boolean`	`true` if the print stream has encountered an error, either on the underlying output stream or during a format conversion.

close

Added in API level 1

void close ()

关闭流并释放与其关联的所有系统资源。关闭以前关闭的流不起作用。

也可以看看：

checkError()

flush

Added in API level 1

void flush ()

刷新流。

也可以看看：

checkError()

format

Added in API level 1

PrintWriter format (Locale l, 
                String format, 
                Object... args)

使用指定的格式字符串和参数将格式化的字符串写入此写入器。如果启用自动刷新，则调用此方法将刷新输出缓冲区。

Parameters
`l`	`Locale`: The locale to apply during formatting. If `l` is `null` then no localization is applied.
`format`	`String`: A format string as described in Format string syntax.
`args`	`Object`: 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 by The Java™ Virtual Machine Specification. The behaviour on a `null` argument depends on the conversion.

Returns
`PrintWriter`	This writer

Throws
	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 the Details section of the formatter class specification.
`NullPointerException`	If the `format` is `null`

format

Added in API level 1

PrintWriter format (String format, 
                Object... args)

使用指定的格式字符串和参数将格式化的字符串写入此写入器。如果启用自动刷新，则调用此方法将刷新输出缓冲区。

总是使用的语言环境是由 Locale.getDefault()返回的语言环境，而不管此对象以前是否有任何其他格式化方法的调用。

Parameters

format String: A format string as described in Format string syntax.

args Object: 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 by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.

Parameters
`format`	`String`: A format string as described in Format string syntax.
`args`	`Object`: 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 by The Java™ Virtual Machine Specification. The behaviour on a `null` argument depends on the conversion.

Returns
`PrintWriter`	This writer

Throws
	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 the Details section of the Formatter class specification.
`NullPointerException`	If the `format` is `null`

print

Added in API level 1

void print (int i)

打印一个整数。根据平台的默认字符编码将由valueOf(int)生成的字符串翻译为字节，并且这些字节以与write(int)方法完全相同的方式写入。

Parameters
`i`	`int`: The `int` to be printed

也可以看看：

toString(int)

print

Added in API level 1

void print (double d)

打印一个双精度浮点数。根据平台的默认字符编码将由valueOf(double)生成的字符串翻译为字节，并且这些字节以与write(int)方法完全相同的方式写入。

Parameters
`d`	`double`: The `double` to be printed

也可以看看：

toString(double)

print

Added in API level 1

void print (boolean b)

打印一个布尔值。根据平台的默认字符编码将由valueOf(boolean)生成的字符串翻译为字节，并且这些字节以与write(int)方法完全相同的方式写入。

Parameters
`b`	`boolean`: The `boolean` to be printed

print

Added in API level 1

void print (char c)

打印一个角色。根据平台的默认字符编码将字符翻译为一个或多个字节，并且这些字节的写入方式与write(int)方法完全相同。

Parameters
`c`	`char`: The `char` to be printed

print

Added in API level 1

void print (long l)

打印一个长整数。根据平台的默认字符编码将由valueOf(long)生成的字符串翻译为字节，并且这些字节以与write(int)方法完全相同的方式写入。

Parameters
`l`	`long`: The `long` to be printed

也可以看看：

toString(long)

print

Added in API level 1

void print (float f)

打印一个浮点数。根据平台的默认字符编码将由valueOf(float)生成的字符串翻译为字节，并且这些字节以与write(int)方法完全相同的方式写入。

Parameters
`f`	`float`: The `float` to be printed

也可以看看：

toString(float)

print

Added in API level 1

void print (String s)

打印一个字符串。如果参数是null则打印字符串"null" 。否则，根据平台的默认字符编码将字符串的字符转换为字节，并且这些字节的写入方式与write(int)方法完全相同。

Parameters
`s`	`String`: The `String` to be printed

print

Added in API level 1

void print (Object obj)

打印一个对象。根据平台的默认字符编码将valueOf(Object)方法生成的字符串转换为字节，并且这些字节的写入方式与write(int)方法完全相同。

Parameters
`obj`	`Object`: The `Object` to be printed

也可以看看：

toString()

print

Added in API level 1

void print (char[] s)

打印一组字符。根据平台的默认字符编码将字符转换为字节，并且这些字节的写入方式与write(int)方法完全相同。

Parameters
`s`	`char`: The array of chars to be printed

Throws
`NullPointerException`	If `s` is `null`

printf

Added in API level 1

PrintWriter printf (String format, 
                Object... args)

使用指定的格式字符串和参数将格式化的字符串写入此写入器的便捷方法。如果启用自动刷新，则调用此方法将刷新输出缓冲区。

表单 out.printf(format, args)的这种方法的调用的行为与调用完全相同

     out.format(format, args)

Parameters

format String: A format string as described in Format string syntax.

Returns
`PrintWriter`	This writer

Throws
	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 the Details section of the formatter class specification.
`NullPointerException`	If the `format` is `null`

printf

Added in API level 1

PrintWriter printf (Locale l, 
                String format, 
                Object... args)

使用指定的格式字符串和参数将格式化的字符串写入此写入器的便捷方法。如果启用自动刷新，则调用此方法将刷新输出缓冲区。

表单 out.printf(l, format, args)的此方法的调用的行为与调用完全相同

     out.format(l, format, args)

Parameters
`l`	`Locale`: The locale to apply during formatting. If `l` is `null` then no localization is applied.
`format`	`String`: A format string as described in Format string syntax.
`args`	`Object`: 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 by The Java™ Virtual Machine Specification. The behaviour on a `null` argument depends on the conversion.

Returns
`PrintWriter`	This writer

Throws
	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 the Details section of the formatter class specification.
`NullPointerException`	If the `format` is `null`

println

Added in API level 1

void println (Object x)

打印一个对象，然后终止该行。此方法首先调用String.valueOf（x）以获取打印对象的字符串值，然后表现得像调用print(String) ，然后调用println() 。

Parameters
`x`	`Object`: The `Object` to be printed.

println

Added in API level 1

void println (char x)

打印一个字符，然后终止该行。该方法表现得好像调用了print(char) ，然后调用了println() 。

Parameters
`x`	`char`: the `char` value to be printed

println

Added in API level 1

void println (boolean x)

打印一个布尔值，然后终止该行。该方法表现得好像调用了print(boolean) ，然后调用了println() 。

Parameters
`x`	`boolean`: the `boolean` value to be printed

println

Added in API level 1

void println (long x)

打印一个长整数，然后终止该行。此方法表现得好像调用print(long) ，然后调用println() 。

Parameters
`x`	`long`: the `long` value to be printed

println

Added in API level 1

void println ()

通过写入行分隔符字符串来终止当前行。行分隔符字符串由系统属性line.separator定义，并不一定是单个换行符（ '\n' ）。

println

Added in API level 1

void println (int x)

打印一个整数，然后终止该行。该方法的行为如同调用print(int) ，然后调用println() 。

Parameters
`x`	`int`: the `int` value to be printed

println

Added in API level 1

void println (String x)

打印一个字符串，然后终止该行。此方法表现得好像调用了print(String) ，然后是println() 。

Parameters
`x`	`String`: the `String` value to be printed

println

Added in API level 1

void println (char[] x)

打印一组字符，然后终止该行。该方法表现得好像调用了print(char[]) ，然后调用了println() 。

Parameters
`x`	`char`: the array of `char` values to be printed

println

Added in API level 1

void println (float x)

打印一个浮点数，然后终止该行。此方法表现得好像调用了print(float) ，然后调用了println() 。

Parameters
`x`	`float`: the `float` value to be printed

println

Added in API level 1

void println (double x)

打印一个双精度浮点数，然后终止该行。此方法表现得好像调用了print(double) ，然后调用了println() 。

Parameters
`x`	`double`: the `double` value to be printed

write

Added in API level 1

void write (int c)

写一个字符。

Parameters
`c`	`int`: int specifying a character to be written.

write

Added in API level 1

void write (char[] buf, 
                int off, 
                int len)

写入一组字符的部分。

Parameters
`buf`	`char`: Array of characters
`off`	`int`: Offset from which to start writing characters
`len`	`int`: Number of characters to write

write

Added in API level 1

void write (String s)

写入一个字符串。此方法不能从Writer类继承，因为它必须抑制I / O异常。

Parameters
`s`	`String`: String to be written

write

Added in API level 1

void write (String s, 
                int off, 
                int len)

写入一部分字符串。

Parameters
`s`	`String`: A String
`off`	`int`: Offset from which to start writing characters
`len`	`int`: Number of characters to write

write

Added in API level 1

void write (char[] buf)

写入一个字符数组。此方法不能从Writer类继承，因为它必须抑制I / O异常。

Parameters
`buf`	`char`: Array of characters to be written

Protected methods

clearError

Added in API level 9

void clearError ()

清除此流的错误状态。

此方法将导致后续调用 checkError()返回 false，直到另一个写入操作失败并调用 setError() 。

setError

Added in API level 1

void setError ()

表示发生错误。

此方法将导致后续调用 checkError()返回 true，直到调用 clearError() 。