常见的SSH执行save方法报错，

报错：Caused by: org.springframework.beans.NotWritablePropertyException: Invalid property 'driverClassName' of bean class [com.mchange.v2.c3p0.ComboPooledDataSource]: Bean property 'driverClassName' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?

页面代码： private static PersonDAO psd;
private static ApplicationContext cxt;
@BeforeClass
public static void setUpBeforeClass() throws Exception {
try {
cxt = new ClassPathXmlApplicationContext("beans.xml");
psd =(PersonDAO)cxt.getBean("serivceBean");
} catch (Exception e) {
e.printStackTrace();
}
}

@Test
public void testSave() {
    psd.save(new Person("xxx"));
}

业务bean:
@Resource private SessionFactory sessionFactoy;

public void save(Person person) {
    sessionFactoy.getCurrentSession().persist(person);
}

实体类：
private Integer id;
private String username;

    public Person(){}
    public Person(String username) {
        this.username = username;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }

beans.xml:
destroy-method="close">
.....