JUnit-无法静态引用类型Customer[closed]中的非静态方法setUsername（String）

Question

我是Java和OOD的新手&一直在尝试为一个小的JDBC项目编写一些测试，但在让测试进入绿色光时遇到了一些问题。这就是我开始的地方，玩了很多次都没有效果。

下面是我的测试：

@Test // 3
public void testThatWhenIAddACustomerThatWHenICallTheGetCustomerMethodInCustomerDAOItReturnsTheUser() {

    CustomerDAO customerDAO = new CustomerDAO();
    customerDAO.setEntityManager(entityManager);
    Customer customer = new Customer();
    Customer.setUsername("Customer1");
    customerDAO.addCustomer(customer);

    Customer customerInDB = customerDAO.getCustomer("Customer1");
    String usernameInDB = customerInDB.getUsername();
    assertEquals("Customer1", customerInDB);

}

我的刀：

public void addCustomer(Customer customer) {
    EntityTransaction entityTransaction = entityManager.getTransaction();
    entityTransaction.begin();
    entityManager.persist(customer);
    entityTransaction.commit();

}

public Customer getCustomer(String username) {
    Customer customerInDB = entityManager.find(Customer.class, username);
    return customerInDB;
}

public void removeCustomer(String username) {

    Customer customerInDB = entityManager.find(Customer.class, username);

    EntityTransaction entityTransaction = entityManager.getTransaction();
    entityTransaction.begin();

    entityManager.remove(customerInDB);
    entityTransaction.commit();

}

我的客户类：

@Entity public class Customer {
@Id public String username;

private int customerId;
private double customerBalance;
private String firstName;
private String lastName;
private String email;


public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

Answer 1

您的问题是：

 Customer.setUsername("Customer1");

您有一个大写C，所以您使用的是类名，而不是变量名。事关重大！