Mybatis (two) three ways to search

<-! Namesapce: the full path to implement understood class (package name + class name) -> 
< Mapper namespace = "ab &" > 
    <-! ID: Method Name 
        parameterType: defining parameters Type 
        resultType: Return Value Type. 
        
        If the return value is List method, written in the generic List resultType because mybatis 
        of jdbc package, data is read row by row 
    -> 
    < SELECT ID = "a selectAll" resultType = "com.zzu.pojo.People" > 
        SELECT from Test * 
    </ SELECT > 
    < SELECT ID = "COUNT" the resultType = "int" >
        select count(*) from test
    </select>
    <select id="_selectAll" resultType="com.zzu.pojo.People">
        select id,name,money from test
    </select>
</mapper>

A, selectList () 

1, the return value List <resultType attribute control>
2, the results are applied to the query need to traverse the demand

List<People> list = session.selectList("a.b.selectAll");
    for(People p : list) {
        System.out.println(p.toString());
    } 

 

二、selectOne() 

1, the return value Object
2, the results are only applicable to the return line of data or variables

int count = session.selectOne("a.b.count");
    System.out.println(count);

 

Three, selectMap () 

1, the return value of the Map
2, need to take a value suitable to the needs of a column data line in the query results
3, Map <key, resultType control>

Map<Object,Object> map = session.selectMap("a.b._selectAll", "name");
    System.out.println(map.toString());