无法在java中使用arraylist参数

我试图将参数传递给构造函数，但我不知道该方法中的arraylist使用什么。 建造商：

public Company(int companyid,String companyname, String companyowner, String startdate, String description,
             ArrayList<String> departments) {
    this.companyid=companyid;
    this.companyname = companyname;
    this.companyowner = companyowner;
    this.startdate = startdate;
    this.description = description;
    this.departments = departments;
}

// Genre is json array
JSONArray companydept = obj.getJSONArray("companyDepartments");
ArrayList<String> departments = new ArrayList<String>();
for (int j = 0; j < companydept.length(); j++) {
     departments.add((String) companydept.get(j));
}

Company company = new Company(obj.getInt("companyID"),
                              obj.getString("comapnyName"),
                              obj.getString("companyOwner"),
                              obj.getString("companyStartDate"),
                              obj.getString("companyDescription"),
                              departments); // <--- Pass the ArrayList here

public Company（int companyid，String companyname，String companyowner，String startdate，String description，
ArrayList部门）{
this.companyid=companyid；
this.companyname=companyname；
this.companyowner=公司所有者；
this.startdate=startdate；
this.description=描述；
这个.部门=部门；
}

在方法中调用参数：

Company company = new Company(obj.getInt("companyID"),obj.getString("comapnyName"),obj.getString("companyOwner"),obj.getString("companyStartDate"),obj.getString("companyDescription"),obj.getString("companyDepartments"));
company.setCompanyid(obj.getInt("companyID"));
company.setCompanyname(obj.getString("comapnyName"));
company.setCompanyowner(obj.getString("companyOwner"));
company.setStartdate(obj.getString("companyStartDate"));
company.setDescription(obj.getString("companyDescription"));


// Genre is json array
JSONArray companydept = obj.getJSONArray("companyDepartments");
ArrayList<String> departments = new ArrayList<String>();
for (int j = 0; j < companydept.length(); j++) {
    departments.add((String) companydept.get(j));
}
company.setDepartments(departments);

Company Company=新公司（obj.getInt（“companyID”）、obj.getString（“comapnyName”）、obj.getString（“companyOwner”）、obj.getString（“companyStart日期”）、obj.getString（“companyDescription”）、obj.getString（“companyDepartments”）；
company.setCompanyid（对象GEINT（“companyID”）；
company.setCompanyname（obj.getString（“comapnyName”）；
company.setCompanyowner（对象getString（“companyOwner”）；
company.setStartdate（对象getString（“companyStartDate”）；
company.setDescription（obj.getString（“companyDescription”）；
//类型是json数组
JSONArray companydept=obj.getJSONArray（“公司部门”）；
ArrayList departments=新建ArrayList（）；
对于（int j=0；j

我不知道该在方法中使用什么。预期的参数是Arraylist，但该方法中使用的实际参数是String，我不知道在那里使用什么。

您很接近

将以下代码移到公司的构造函数之前（在调用新公司之前）

---

您有几个选择：

1） 您可以从

Company

构造函数中删除

ArrayList departments

参数，只需使用

Company.setDepartments（departments）设置器，就像你现在做的那样

2） 首先创建
ArrayList部门
，然后将其传递给构造函数：

public Company(int companyid,String companyname, String companyowner, String startdate, String description,
             ArrayList<String> departments) {
    this.companyid=companyid;
    this.companyname = companyname;
    this.companyowner = companyowner;
    this.startdate = startdate;
    this.description = description;
    this.departments = departments;
}

// Genre is json array
JSONArray companydept = obj.getJSONArray("companyDepartments");
ArrayList<String> departments = new ArrayList<String>();
for (int j = 0; j < companydept.length(); j++) {
     departments.add((String) companydept.get(j));
}

Company company = new Company(obj.getInt("companyID"),
                              obj.getString("comapnyName"),
                              obj.getString("companyOwner"),
                              obj.getString("companyStartDate"),
                              obj.getString("companyDescription"),
                              departments); // <--- Pass the ArrayList here

您可以使用字符串生成器或缓冲区创建逗号分隔的字符串，然后将其传递给构造函数。这很简单。在实例化Company对象之前，您是否尝试过创建ArrayList，并将其传递给构造函数？
public Company(int companyid,String companyname, 
               String companyowner, String startdate, 
               String description, JSONArray companydept) {
     this.companyid=companyid;
     this.companyname = companyname;
     this.companyowner = companyowner;
     this.startdate = startdate;
     this.description = description;

    // build it in the constructor here:
    this.departments = new ArrayList<String>();
    for (int j = 0; j < companydept.length(); j++) {
         departments.add((String) companydept.get(j));
    }  
}