public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException
        {
            String line = value.toString(); // 读取源数据
            try
            {
                // 数据处理
                // 如果是表头，不处理
                if(line.contains("EMPNO") || line.contains("DEPTNO") || line.contains("----"))
                {
                    return;
                }
                else
                {
                    String inputFileName = ((FileSplit) context.getInputSplit()).getPath().getName();
                    if("emp.txt".equals(inputFileName))
                    {// 员工表
                        String[] fields = Parser.parse(line, EMP_SPLIT_LINE, " ");
                        String empNo = fields[0].trim();
                        String eName = fields[1].trim();
                        String job = fields[2].trim();
                        String mgr = fields[3].trim();
                        String hiredate = fields[4].trim();
                        int sal = "".equals(fields[5].trim()) ? 0 : Integer.parseInt(fields[5].trim());
                        int comm = "".equals(fields[6].trim()) ? 0 : Integer.parseInt(fields[6].trim());
                        String deptNo = fields[7].trim();
                        EmpWritable emp = new EmpWritable(empNo, eName, job, mgr, hiredate, sal, comm, deptNo);
                        context.write(emp.getDeptNo(), new EmpDeptWritable(emp));
                    }
                    else if("dept.txt".equals(inputFileName))
                    {
                        String[] fields = Parser.parse(line, DEPT_SPLIT_LINE, " ");
                        String deptNo = fields[0].trim();
                        String dName = fields[1].trim();
                        String loc = fields[2].trim();
                        DeptWritable dept = new DeptWritable(deptNo, dName, loc);
                        context.write(dept.getDeptNo(), new EmpDeptWritable(dept));
                    }
                }
            }
            catch(java.lang.ArrayIndexOutOfBoundsException e)
            {
                context.getCounter(Counter.LINESKIP).increment(1); // 出错令计数器+1
                return;
            }
        }