<select id="userNameValidate" parameterType="String" resultType="Integer"> 
   select count(*) from user where username like #{value} 
</select>   
<select id="nickNameValidate" parameterType="String" resultType="Integer"> 
  select count(*) from user where nickname like #{value}    
</select> 

// 验证 nickname 是否重复 
public Integer nickNameValidate(@Param("value")String value); 
// 验证 username 是否重复 
// 防止查询不到值为空，用Integer 
public Integer userNameValidate(@Param("value")String value); 

int nameValidate(String name,String value); 

 // 验证是否重名：userName、nickName,返回该名字数量,0 没重名,1重名 
ublic int nameValidate(String name,String value) { 
Integer Validate ; 
System.out.println("impl:"+name +"==="+value); 
if(name.equals("userName")) 
  Validate = userMapper.userNameValidate(value); 
else 
  Validate = userMapper.nickNameValidate(value); 
if(Validate == null) 
  return 0; 
return Validate.intValue();