java - 如何保证一个I/O流的关闭？

Question

考虑这个函数:

import java.io.IOException;
import java.io.Reader;

class StreamPrinter {

    void print(Reader reader) throws IOException {
        int code = reader.read();
        while (code != -1) {
            System.out.print((char) code);
            code = reader.read();
        }

        reader.close();
    }

}

出现异常和错误时如何关闭流？

Answer 1

正如发布的那样，您可以使用 finally block ，例如

void print(Reader reader) throws IOException {
    try {
        int code = reader.read();
        while (code != -1) {
            System.out.print((char) code);
            code = reader.read();
        }
    } finally {  
        reader.close();
    }
}

此外，编写 while 循环的更惯用方法类似于

void print(Reader reader) throws IOException {
    int code;
    while ((code = reader.read()) != -1) {
        System.out.print((char) code);
    }
}

然后使用调用者的try-with-resources；喜欢

try (Reader reader = ...) {
    print(reader);
}