Question

“约翰”，“ 100.00”，“ 200.00”

如何读取文本文件的内容，然后在引号下打印字符串。

输出应为准100.00 200.00

String CUSTOMER, CURRENT, NEW;
    Scanner sc = new Scanner(str);
    sc.useDelimiter(",");
    while(sc.hasNext()){
        CUSTOMER = sc.next();
        CURRENT = sc.next();
        NEW = sc.next();
           System.out.println("" + CUSTOMER + " " + CURRENT + 
             " " + NEW);  
          }
          sc.close();

如何将标记与引号分开。我得到的上述代码的输出是这个 “ Jhon”“ 100.00”“ 200.00”

Answer 1

您可以通过以下命令获得所需的输出：

public static void main(String[] args) {
    Pattern p = Pattern.compile(".*?\\\"(.*?)\\\".*?");
    Matcher m = p.matcher("\"John\",\"100.00\",\"200.00\"");

    while (m.find()) {
        System.out.println(m.group(1));
    }
}

说明

.*?   - anything
\\\" - quote (escaped)
(.*?) - anything (captured)
\\\" - another quote
.*?  - anything

输出

John
100.00
200.00

Answer 2

https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html

扫描仪还可以使用除空格以外的定界符。此示例从字符串中读取多个项目：

 String input = "1 fish 2 fish red fish blue fish";
 Scanner s = new Scanner(input).useDelimiter("\\s*fish\\s*");

因此，您可以避免在substring（1，len-1）和useDelimiter（\“，\”）中使用首尾加引号，并在内部加上3个符号。

    String str = "\"John\",\"100.00\",\"200.00\"";
    System.out.println(str);
    String CUSTOMER, CURRENT, NEW;
    Scanner sc = new Scanner(
        str.substring(1,str.length()-1)  // <--- here substring 
    );
    sc.useDelimiter("\",\""); // <---- here your split: <token>","<token>

    while(sc.hasNext()){
        CUSTOMER = sc.next();
        CURRENT = sc.next();
        NEW = sc.next();
        System.out.println("" + CUSTOMER + " " + CURRENT + " " + NEW);  
    }
    sc.close();

Answer 3

这是完成任务的另一种方法：

String line, customerName, currentVal, newVal;
try (Scanner sc = new Scanner(new File("salesrep.txt"))) {
    while (sc.hasNextLine()) {
        line = sc.nextLine().replace("\"", "");
        //skip blank lines (if any)
        if (line.equals("")) {
            continue;
        }
        String[] lineData = line.split(",");
        customerName = lineData[0];
        currentVal = lineData[1]; // or:  double currentVal = Double.parseDouble(lineData[1]);
        newVal = lineData[2];     // or:  double newVal = Double.parseDouble(lineData[2]);
        System.out.println("" + customerName + " " + currentVal + " " + newVal);
    }
}
catch (FileNotFoundException ex) {
    ex.printStackTrace();
}

读取由分隔符分隔的texfile的内容

3 个答案: