Java Java类
这是一个字符流类，其源是一个字符串。
构造函数：
方法 ：
- void close() ：关闭流并释放与之关联的任何系统资源。一旦流被关闭，进一步的 read()、ready()、mark() 或 reset() 调用将抛出 IOException。关闭以前关闭的流没有效果。
Syntax :public void close() - void mark(int readAheadLimit) ：标记流中的当前位置。对 reset() 的后续调用会将流重新定位到该点。
Syntax :public void mark(int readAheadLimit) throws IOException Parameters: readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. Because the stream's input comes from a string, there is no actual limit, so this argument must not be negative, but is otherwise ignored. Throws: IllegalArgumentException IOException - boolean markSupported() ：判断此流是否支持 mark() 操作，它支持。
Syntax :public boolean markSupported() Returns: true if and only if this stream supports the mark operation. - int read() ：读取单个字符。
Syntax :public int read() throws IOException Returns: The character read, or -1 if the end of the stream has been reached Throws: IOException - int read(char[] cbuf, int off, int len) ：字符读入数组的一部分。
Syntax :public int read(char[] cbuf, int off, int len) throws IOException Parameters: cbuf - Destination buffer off - Offset at which to start writing characters len - Maximum number of characters to read Returns: The number of characters read, or -1 if the end of the stream has been reached Throws: IOException - boolean ready() ：判断该流是否准备好被读取。
Syntax :public boolean ready() throws IOException Returns: True if the next read() is guaranteed not to block for input Throws: IOException - void reset() ：将流重置为最近的标记，如果从未标记过，则重置为字符串的开头。
Syntax :public void reset() throws IOException Throws: IOException - long skip(long ns) ：跳过流中指定数量的字符。返回跳过的字符数。
ns 参数可能为负数，即使 Reader 超类的 skip 方法在这种情况下会抛出异常。 ns 的负值导致流向后跳过。负返回值表示向后跳过。不能向后跳过字符串的开头。如果整个字符串已被读取或跳过，则此方法无效，始终返回 0。
Syntax :public long skip(long ns) throws IOException Parameters: ns - The number of characters to skip Returns: The number of characters actually skipped Throws: IOException
程序 ：
//Java program demonstrating StringReader methods
import java.io.IOException;
import java.io.StringReader;
class StringReaderDemo
{
public static void main(String[] args) throws IOException
{
StringReader str = new StringReader("GeeksforGeeks");
char c[]=new char[7];
//illustrating markSupported()
if(str.markSupported())
{
System.out.println("Mark method is supported");
// illustrating mark()
str.mark(100);
}
//illustrating skip() method
str.skip(5);
//whether this stream is ready to be read.
if(str.ready())
{
//illustrating read() method
System.out.print((char)str.read());
//illustrating read(char cff[],int off,int len)
str.read(c);
for (int i = 0; i <7 ; i++)
{
System.out.print(c[i]);
}
}
//illustrating reset() method
str.reset();
for (int i = 0; i < 5; i++)
{
System.out.print((char)str.read());
}
//illustrating close()
str.close();
}
}
输出 ：
Mark method is supported
forGeeksGeeks