Java BufferedReader类从字符输入流中读取文本,缓冲读取的字符以实现字符、数组和字符串的高效读取。您可以将缓冲区大小指定为构造函数中的第二个参数。
设计师:
BufferedReader(Reader in) // Creates a character input buffer stream that uses the default buffer size.
BufferedReader(Reader in, int sz) // Creates a character input buffer stream that uses the specified size.
方法:
close() // close the stream
mark(int readAheadLimit) // mark the position in the stream
markSupported() // does it support thread tagging
int read() // read buffer
int read(char[] cbuf, int off, int len) // read buffer
String readLine() // next line
boolean ready() // can the thread read
reset() // reset stream
skip(long n) // skip characters
使用 BufferedReader 和 BufferedWriter 类的示例: 读取文件:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class FileReaderExample {
public static void main(String[] args) {
String inputFileName = "file.txt";
try (BufferedReader reader = new BufferedReader(new FileReader(inputFileName))) {
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line + "\n");
}
}
catch (IOException e) {
e.printStackTrace();
}
}
}
Java BufferedWriter 类将文本写入字符输出流,对写入的字符进行缓冲,以实现字符、数组和字符串的高效写入。您可以将缓冲区大小指定为构造函数中的第二个参数。 设计师:
BufferedWriter(Writer out) // Creates a character output buffer stream that uses the default buffer size.
BufferedWriter(Writer out, int sz) // Creates a character output buffer stream that uses the specified size.
方法:
close() // close the stream
flush() // pass data from buffer to Writer
newLine() // wrap to new line
write(char[] cbuf, int off, int len) // write to buffer
write(int c) // write to buffer
write(String s, int off, int len) // write to buffer
使用 Java BufferedReader 和 BufferedWriter 类的示例: 写入文件
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
public class FileWritterExample {
public static void main(String[] args) {
String outputFileName = "file.txt";
String[] array = { "one", "two", "three", "four" };
try (BufferedWriter writter = new BufferedWriter(new FileWriter(outputFileName))) {
for (String value : array) {
writter.write(value + "\n");
}
}
catch (IOException e) {
e.printStackTrace();
}
}
}
FileWriter
立即将数据写入磁盘并每次访问它,缓冲区充当包装器并加速应用程序。缓冲区会将数据写入自身,然后将一大块文件写入磁盘。 我们从控制台读取数据并将其写入文件:
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
public class ConsoleReaderExample {
public static void main(String[] args) {
String outputFileName = "file.txt";
try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))) {
try (BufferedWriter writter = new BufferedWriter(new FileWriter(outputFileName))) {
String line;
while (!(line = reader.readLine()).equals("exit")) { // Break the loop when writing the line exit
writter.write(line);
}
}
}
catch (IOException e) {
e.printStackTrace();
}
}
}
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