java - OpenCSV - 将多个 CSV 列映射到单个 bean 属性

Question

我有一个要求，

将两个 CSV 列合并为一个 bean 属性。

对列值执行简单的数学运算并映射到 bean 属性。

想知道是否可以使用 OpenCSV 注释进行类似的操作。

输入CSV

User ID, First Name, Last Name, Worked Minutes
1234,Jon,Snow,60
1235,Rob,Stark,30

bean

public class Employee {

  @CsvBindByName(column = "Employee ID")
  private String userId;

  //this should be "First Name, Last Name"
  private String employeeName;

  //this should be Worked Minutes/60
  private String workedHours;

  //getters and setters

}

我设法做到这一点的唯一方法是将列映射为单独的属性( userId 、 firstName 、 lastName 、 workedMinutes )，然后修改 employeeName和 workedHours getter 方法，但我觉得应该有更好的方法来做到这一点。

Answer 1

我不知道如何用 OpenCSV 做到这一点，但我写了一个名为 jflat-core 的库。可以处理对象和平面文件之间的这种复杂映射。

        CSVReader<Employee> csvReader = CSVReader
                .createWithHeaderMapping(Employee.class,
                        new String[] {"User ID", "First Name", "Last Name", "Worked Minutes"},
                        new String[] {"userId", "firstName", "lastName", "workedHours" });
        //register a special converter for the property workedHours
        csvReader.registerConverter("workedHours",
                minutes -> String.valueOf(Double.valueOf(minutes)/60.0));
        List<Employee> employees = csvReader.readAllWithCallback("employees.csv",
                //The callback can be used to help map attributes from the raw record to the target bean
                (record, employee) -> {
                    String name = String.format("%s %s", record.get("First Name"), record.get("Last Name"));
                    employee.setEmployeeName(name);
                });
        assertEquals(2, employees.size());
        assertEquals("Jon Snow", employees.get(0).getEmployeeName());
        assertEquals("0.5", employees.get(1).getWorkedHours());