我可以使用 map 为 java8 流中的其他对象设置值吗？

Question

Am I allowed to write code this way?

我可以在 map 方法中使用 setter 将值设置为使用流的其他对象吗？

try (BufferedReader bufferedReader = new BufferedReader(new FileReader(csvPath))) {
        List<Employee> employees = bufferedReader
                .lines()
                .skip(1)
                .map(l -> {
                    String[] lines = l.split(",");
                    Employee employee = new Employee();
                    employee.setEmployeeId(Long.parseLong(lines[0]));
                    employee.setFullName(lines[1] + " " + lines[2] + " " + lines[3]);
                    employee.setGender(lines[4]);
                    employee.setEmail(lines[5]);
                    employee.setSalary(Double.parseDouble(lines[6]));
                    employee.setState((lines[7]));
                    return employee;
        }).collect(Collectors.toList());

Answer 1

是的，你可以。虽然我不建议这样做。

只需将该逻辑提取到单独的方法中即可：

Employee parseEmployee(String line) {
    String[] columns = line.split(",");
    Employee employee = new Employee();
    employee.setEmployeeId(Long.parseLong(columns[0]));
    employee.setFullName(columns[1] + " " + columns[2] + " " + columns[3]);
    employee.setGender(columns[4]);
    employee.setEmail(columns[5]);
    employee.setSalary(Double.parseDouble(columns[6]));
    employee.setState((columns[7]));
    return employee;
}

然后只需将方法引用传递给map：

List<Employee> employees = bufferedReader.lines()
                                         .skip(1)
                                         .map(this::parseEmployee)
                                         .collect(toList());

这将使您的代码更具可读性和更易于维护。

Answer 2

我会建议将逻辑移到Employee构造函数中

public Employee(String[] lines) {
  this.employeeId = Long.parseLong(lines[0]);
  this.fullName = lines[1] + " " + lines[2] + " " + lines[3];
  this.gender = lines[4];
  this.email = lines[5];
  this.salary = Double.parseDouble(lines[6]);
  this.state = lines[7];

 }

然后只需使用构造函数创建Employee 对象

List<Employee> employees = bufferedReader
            .lines()
            .skip(1)
            .map(l-> l.split(","))
            .map(Employee::new)
            .collect(Collectors.toList());