Java从控制台读入数据的几种技巧
发布时间:2021-12-18 14:50:56 所属栏目:教程 来源:互联网
导读:根据东莞站长网 Www.0769Zz.Com报道 这里记录Java中从控制台读入信息的几种方式,已备后查! (1)JDK 1.4(JDK 1.5和JDK 1.6也都兼容这种方法) public class TestConsole1 { public static void main(String[] args) { String str = readDataFromConsole(Pleas
根据东莞站长网 Www.0769Zz.Com报道
这里记录Java中从控制台读入信息的几种方式,已备后查! (1)JDK 1.4(JDK 1.5和JDK 1.6也都兼容这种方法) public class TestConsole1 { public static void main(String[] args) { String str = readDataFromConsole("Please input string:); System.out.println("The information from console: + str); } /** * Use InputStreamReader and System.in to read data from console * * @param prompt * * @return input string */ private static String readDataFromConsole(String prompt) { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String str = null; try { System.out.print(prompt); str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } return str; } } (2)JDK 1.5(利用Scanner进行读取) public class TestConsole2 { public static void main(String[] args) { String str = readDataFromConsole("Please input string:"); System.out.println("The information from console:" + str); } /** * Use java.util.Scanner to read data from console * * @param prompt * * @return input string */ private static String readDataFromConsole(String prompt) { Scanner scanner = new Scanner(System.in); System.out.print(prompt); return scanner.nextLine(); } } Scanner还可以很方便的扫描文件,读取里面的信息并转换成你要的类型,比如对“2 2.2 3.3 3.33 4.5 done”这样的数据求和,见如下代码: public class TestConsole4 { public static void main(String[] args) throws IOException { FileWriter fw = new FileWriter("num.txt"); fw.write("2 2.2 3.3 3.33 4.5 done"); fw.close(); System.out.println("Sum is "+scanFileForSum("num.txt")); } public static double scanFileForSum(String fileName) throws IOException { double sum = 0.0; FileReader fr = null; try { fr = new FileReader(fileName); Scanner scanner = new Scanner(fr); while (scanner.hasNext()) { if (scanner.hasNextDouble()) { sum = sum + scanner.nextDouble(); } else { String str = scanner.next(); if (str.equals("done")) { break; } else { throw new RuntimeException("File Format is wrong!"); } } } } catch (FileNotFoundException e) { throw new RuntimeException("File " + fileName + " not found!"); } finally { if (fr != null) fr.close(); } return sum; } } ![]() (编辑:我爱故事小小网_铜陵站长网) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |