Java字符串解析错误

Question

嘿有人可以帮我解决我遇到的错误吗？我正在从文件中取出行并检查它们是低中还是高。如果字符串为空，我想读取文件中的下一行。我认为错误是当我将刺痛解析为 double 时。这是我的代码，如有任何帮助，请采纳! 首先这是我的错误

Exception in thread "main" java.lang.NumberFormatException: empty String
    at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
    at java.lang.Double.parseDouble(Unknown Source)
    at BSCQueryManager.displayBar(BSCQueryManager.java:431)
    at BSCQueryManager.main(BSCQueryManager.java:57)

这是我的代码

String vMag;
            String data;
            double v;
            int highCount = 0;
            int medCount = 0;
            int lowCount = 0;
            // read file
            File inFile = new File("bsc.dat");   
            Scanner starFile = new Scanner(inFile);
            // while there is a vmag
            while(starFile.hasNext()){
                // read next line
                data = starFile.nextLine();
                data = data.substring(102, 107);
                data.trim();
            // if no vmag read next line
                if(data.trim()!= ""){
                    v = Double.parseDouble(data);
                    // if vmag is > 6.0 add to countHigh
                    if (v > 6){
                        highCount++;
                    }
                    // if vmag is 5-6 add to countMed
                    if (v >= 5 && v <= 6){
                        medCount++;
                    }
                    // if vmag is < 5 add to countLow
                    if (v < 5){
                        lowCount++;
                    }
                // end if
                }
            // end while
            }

            // display label
            System.out.println(label);
            System.out.println(highCount);
            System.out.println(lowCount);
            System.out.println(medCount);

Answer 1

尝试替换:

data.trim();
// if no vmag read next line
if(data.trim()!= ""){

与

data = data.trim();
// if no vmag read next line
if(data.length > 0){