Bean property 'xxx' is not writable or has an invalid setter method

出现此问题的原因是在ApplicationContext.xml中配置有问题，里面的bean的属性名称用 与 注入的类名称不一致

applicationContext.xml

userdao" ref="testdao">

userServiceImpl

private UserDao userdao;

public void setUserdao(UserDao userdao) {
this.userdao = userdao;
}

红色部分名称要一致。