Java中Reader类的ready()方法用于检查此Reader是否已准备好被读取。它返回一个布尔值，该值指示阅读器是否准备就绪。

用法:

public void ready()

参数：此方法不接受任何参数

返回值：此方法返回一个布尔值，该值指示此Reader是否已准备好被读取。如果准备就绪，则返回true。否则返回false。

异常：如果输入输出时发生某些错误，则此方法将引发IOException。

下面的方法说明了ready()方法的用法方式：

程序1:

// Java program to demonstrate

// Reader ready() method

import java.io.*;

import java.util.*;

class GFG {

public static void main(String[] args)

{

try {

String str = "GeeksForGeeks";

// Create a Reader instance

Reader reader

= new StringReader(str);

// Check if the Reader is

// ready to be read using ready()

System.out.println("Is Reader ready "

+ "to be read: "

+ reader.ready());

// Get the character

// to be read from the stream

int ch;

// Read the first 5 characters

// to this reader using read() method

// This will put the str in the stream

// till it is read by the reader

for (int i = 0; i < 5; i++) {

ch = reader.read();

System.out.println("\nInteger value "

+ "of character read: "

+ ch);

System.out.println("Actual "

+ "character read: "

+ (char)ch);

}

reader.close();

}

catch (Exception e) {

System.out.println(e);

}

}

}

输出：

Is Reader ready to be read: true

Integer value of character read: 71

Actual character read: G

Integer value of character read: 101

Actual character read: e

Integer value of character read: 101

Actual character read: e

Integer value of character read: 107

Actual character read: k

Integer value of character read: 115

Actual character read: s

程序2:

// Java program to demonstrate

// Reader ready() method

import java.io.*;

import java.util.*;

class GFG {

public static void main(String[] args)

{

try {

String str = "GeeksForGeeks";

// Create a Reader instance

Reader reader

= new StringReader(str);

reader.close();

// Check if the Reader is

// ready to be read using ready()

System.out.println("Is Reader ready "

+ "to be read: "

+ reader.ready());

// Get the character

// to be read from the stream

int ch;

// Read the first character

// to this reader using read() method

// This will put the str in the stream

// till it is read by the reader

ch = reader.read();

System.out.println("\nInteger value "

+ "of character read: "

+ ch);

System.out.println("Actual "

+ "character read: "

+ (char)ch);

reader.close();

}

catch (Exception e) {

System.out.println(e);

}

}

}

输出：

java.io.IOException: Stream closed