Java字符串索引超出范围: -45

Question

我正在尝试接受来自用户的文件(通过 GUI 中的文件浏览器)并逐行读取文件。基本上我的兴趣是知道字符位置 60 和 80 之间到底写了什么，因为在此基础上我得出一些结论，需要做出一些决定(特别是读取 rinex.o 文件)。但我收到错误 Exception in thread "AWT-EventQueue-0"java.lang.StringIndexOutOfBoundsException: String index out of range: -45在行:String typeField=line.substring(60,line.length());并且无法继续前进。

感谢您提前提供的帮助。

  void parseRinexOFile(File inputfile) throws FileNotFoundException, IOException{
       File obsFile= inputfile;
//       if (obsFile.exists()) //Code to test if the file exists.
//               System.out.println("Hello, I exist"+ obsFile.getPath());
       // Create File Stream, Stream Reader and Bufferreader
        streamObs = new FileInputStream(obsFile);
        inStreamObs = new InputStreamReader(streamObs);
        buffStreamObs = new BufferedReader(inStreamObs);
        BufferedReader in = new BufferedReader(new FileReader(obsFile));
        String line="";
        while((line = in.readLine()) != null)
                {
                    String typeField=line.substring(60,line.length());
                    typeField=typeField.trim();
                    if (typeField.equals("RINEX VERSION / TYPE")) {//Check if the observation file identifier is missing else find the version of the file

                    if (!line.substring(20, 21).equals("O")) {

                            // Error if observation file identifier was not found
                            System.err.println("Observation file identifier is missing in file "
                                                            + obsFile.toString() + " header");
                             ver = 0;

                    } else if (line.substring(5, 7).equals("3.")){                                                  
                            ver = 3;                                                        
                    } else if (line.substring(5, 9).equals("2.12")){                                                        
                            ver = 212;                                                      
                    } else {                                                        
                            ver = 2;  
                            System.out.println(" Current version:"+ver);
                    }                                               
                }
                    //System.out.println(line);

                }
                in.close(); 

        } 

Answer 1

发生异常是因为输入行少于 60 个字符。在调用 substring() 之前需要检查行长度。