java - 设置值时出现 NullPointerException

Question

我在操作类中遇到 jsp 问题。当我编写这段代码时:

listRehber.add(new Rehber(
    rs.getString("KISI_ID").toString(),
    rs.getString("AD").toString(),
    rs.getString("SOYAD").toString(),
    rs.getString("UNVANI").toString(),
    rs.getString("GOREVI").toString(),
    rs.getString("FIRMA").toString(),
    rs.getString("ADRES").toString(),
    rs.getString("TEL").toString(),
    rs.getString("FAX").toString(),
    rs.getString("GSM").toString(),
    rs.getString("MAIL").toString(),
    rs.getString("WEB").toString()));
}

因为 db 可能会是空值。例如，数据库将具有“名称”值，但不会具有“传真”。我怎样才能传递这个空指针异常非常感谢您

我的Rehber.class

public class Rehber {
    private String adi = "";
    private String soyadi = "";
    private String unvani = "";
    private String gorevi = "";
    private String firma = "";
    private String adres = "";
    private String tel = "";
    private String fax = "";
    private String gsm = "";
    private String mail = "";
    private String web = "";
    private String id = "";

    public Rehber(String id, String adi, String soyadi, String unvani,
            String gorevi, String firma, String adres, String tel, String fax,
            String gsm, String mail, String web) {

        this.adi = adi; 
        this.soyadi = soyadi;
        this.unvani = unvani;   
        this.gorevi = gorevi;       
        this.firma = firma;     
        this.adres = adres;     
        this.tel = tel;     
        this.fax = fax; 
        this.gsm = gsm;     
        this.mail = mail;   
        this.web = web;
        this.id = id;
    }
}

以及获取/设置方法

Answer 1

您已经在调用ResultSet#getString，它将返回一个String。无需在 String 中调用 toString，因此请删除参数的该方法调用。

listRehber.add(
    new Rehber(
        rs.getString("KISI_ID"),
        rs.getString("AD"),
        rs.getString("SOYAD"),
        rs.getString("UNVANI"),
        rs.getString("GOREVI"),
        rs.getString("FIRMA"),
        rs.getString("ADRES"),
        rs.getString("TEL"),
        rs.getString("FAX"),
        rs.getString("GSM"),
        rs.getString("MAIL"),
        rs.getString("WEB")
    ));