我实际上正在使用 postman 向我的 REST API 发送登录请求,但它给了我一个 javaNullpointer
异常。这是因为在模型类中我的变量之一没有获得值。我的模型类中未调用 setPhone_Number()
函数。因此 phone_number
变量为空。
感谢帮助。
这是我的错误屏幕截图 eclipse error for null pointer 这是我通过 postman 发送的内容 Postman
这是登录 dao 类。
public class LoginDao {
private String password;
private String phone_number;
public LoginDao(){
phone_number = null;
password = null;
}
public Response doLogin(login logg, String user_type) throws SQLException{
ResultSet rs = null;
boolean userType = true;
//if userType is resource then boolean is false, if userType is user then boolean is true.
//logg.setPhone_Number(phone_number);
DBConnection dbConnection = new DBConnection();
//Connection connection = dbConnection.getConnection();
this.phone_number = logg.getPhone_Number();
this.password = logg.getPassword();
try{
if(user_type.equalsIgnoreCase("Rider")) {
rs = dbConnection.runSql("select rider_id, phone_number, password from rider");
userType = true;
}
else if(user_type.equalsIgnoreCase("Driver")) {
rs = dbConnection.runSql("select driver_id, phone_number, password from driver");
userType = false;
}
while(rs.next()){
System.out.println(phone_number);
System.out.println(rs.getString("phone_number"));
System.out.println("user"+user_type);
if((this.phone_number.equals(rs.getString("phone_number"))) && (this.password.equals(rs.getString("password")))){
这是模型类登录
public class login {
private String phone_number;
private String password;
public login(){
}
public String getPhone_Number() {
System.out.println("getting "+phone_number);
return phone_number;
}
public void setPhone_Number(String phone_number) {
System.out.println("seting "+phone_number);
this.phone_number = phone_number;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
System.out.println("seting "+password);
this.password = password;
}
}
这是loginResource.java
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import static javax.ws.rs.core.MediaType.APPLICATION_JSON;
import java.sql.SQLException;
import javax.ws.rs.Consumes;
import io.github.yasirfaisal21.schoolvan.schoolvan.dao.LoginDao;
import io.github.yasirfaisal21.schoolvan.schoolvan.model.login;
@Path("login")
public class loginResource {
@Produces(MediaType.APPLICATION_JSON)
@Consumes(APPLICATION_JSON)
@POST
public Response doLogin(login log,@QueryParam("user_type") String user_type )
throws SQLException{
LoginDao loginDao = new LoginDao();
if(user_type.equalsIgnoreCase("Rider"))
return loginDao.doLogin(log,"Rider");
else
return loginDao.doLogin(log,"Driver");
}
}
最佳答案
在您的 login.java
类中,替换:
private String Phone_number;
与
私有(private)字符串电话号码;
并按照如下方式更新其 getter 和 setter:
public String getPhoneNumber() {
return phoneNumber;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
关于REST API 中的 Java 空指针异常,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/51147974/