关于ssm框架使用form表单进行登陆，返回的admin永远是null，只能返回fall页面

Question

dao层代码

public Admin   findByAdminName(@Param("adminname") String adminname);

mappe.xml代码

    <select id="findByAdminName" resultType="model.Admin" parameterType="java.lang.String">
        select * from t_admin where admin_name=#{adminname}

    </select>

service接口和实现

// 用户登录
   Admin logincheck(String adminname,String adminpwd);
     //实现
     @Autowired
    private AdminMapper adminMapper;

    public Admin logincheck(String adminname, String adminpwd) {
        Admin admin = adminMapper.findByAdminName(adminname);
        if (admin!=null && admin.getAdminPwd().equals(adminpwd)){


            return admin;
        }

        return null;
```contoller层

//调用service方法
Admin admin = new Admin();
admin = adminService.logincheck(adminname,adminpwd);
System.out.println(admin);
System.out.println(adminname+adminpwd);
if (admin!=null){
model.addAttribute("admin",admin);
return "adminindex";
}
return "fall";

Answer 1

select * from t_admin where admin_name=#{adminname,jdbcType=VARCHAR}
这样看看
检查下数据库，你输入的用户名密码是否的确存在。