MyBatis! Passing multiple parameter to Mapper DAO

Question

I am trying to send multiple parameter to Mapper function defined in DAO implementation but unable to send more than 1 parameter in the case when parameter are not holder of any class. I mean how can I modify the following code-

obj.getName(int a, int b);

In DAO implementation

public void getAllName() throws PersistenceException {
        SqlSession session = sf.openSession();
        try {
            session.selectList("getNames");         
        } finally {
            session.close();
        }
    }

I want to send a and b to query getNames.

Thanks in advance.

Answer 1

If you are using DAO implementation then you can do this by using a HashMap. Just add the key-value pair in HashMap and add it in function call and you can access it in the mapper.xml using "key".

Answer 2

Use a Mapper.

interface Mapper
{
     @Select( " select names from names_table where a = #{fieldA} and b = #{fieldB}" )
     List<String> getNames(  @Param("fieldA") String fieldA, @Param("fieldB") String fieldB)
}

The @Param tag allows you to specify what you can use to access the parameter in the sql map. This example shows a @Select tag, but it works the same as xml.

then change your code,

public List<String> getAllName() throws PersistenceException {
        SqlSession session = sf.openSession();
        try 
        {
             Mapper mapper = session.getMapper(Mapper.class);
            return mapper.getNames("a","b");
        } finally {
            session.close();
        }
    }

Read the user guide for more information.