Mybatis映射器(一)

XML查询参数：

parameterType：可以给出类别名，全名等.

resultType:查询结果，可以为 int,float,map等不可以与resultMap同时使用。

resultMap: 映射集的引用可以配置映射规则，级联，typeHandler等，是mybatis最复杂的元素。

本文返回是resultType。

查询方法可以在parameterType设置为单个参数XML设置为int,string等，多个参数可以设置为map

<select id="getRoleUseResultMap" parameterType="long" resultMap="roleMap">
select id, role_name, note from t_role where id = #{id}
</select>

<select id="findRolesByMap" parameterType="map" resultType="role">
select id, role_name as roleName, note from t_role
where role_name like
concat('%', #{roleName}, '%')
and note like concat('%', #{note}, '%')
</select>

或者多个参数避免map可读性差时可以用在Mapper java中注解（此时XML中没有parameterType）

public List<Role> findRolesByAnnotation(@Param("roleName") String rolename, @Param("note") String note);

<select id="findRolesByAnnotation" resultType="role">
select id,
role_name as roleName, note from t_role
where role_name like
concat('%', #{roleName}, '%')
and note like concat('%', #{note}, '%')
</select>

亦或是通过java bean传递多个参数：

public class RoleParams {
private String roleName;
private String note;

public String getRoleName() {
return roleName;
}
public void setRoleName(String roleName) {
this.roleName = roleName;
}
public String getNote() {
return note;
}
public void setNote(String note) {
this.note = note;
}
}

mapper:

public List<Role> findRolesByBean(RoleParams roleParam);

XML:parameterType="com.ssm.chapter5.param.RoleParams".

<select id="findRolesByBean" parameterType="com.ssm.chapter5.param.RoleParams"
resultType="role">
select id, role_name as roleName, note from t_role
where
role_name like
concat('%', #{roleName}, '%')
and note like concat('%',#{note}, '%')
</select>

-----------------------------------------------------------------------------------------------

测试：

case 1:简单查询

<select id="getRole" parameterType="long" resultType="com.ssm.chapter5.pojo.Role">

select id,

role_name as roleName, note from t_role where id = #{id}

</select>
mapper:

public Role getRole(Long id);


public static void testGetRole() {

SqlSession sqlSession = null;

try {

sqlSession = SqlSessionFactoryUtils.openSqlSession();

RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);

Role role = roleMapper.getRole(1L);

System.out.println(role.getRoleName());

} catch(Exception ex) {

ex.printStackTrace();

} finally {

if (sqlSession != null) {

sqlSession.close();

}

}

}

case 2: map 查询：

    <select id="findRolesByMap" parameterType="map" resultType="role">

        select id, role_name as roleName, note from t_role

        where role_name like

        concat('%', #{roleName}, '%')

        and note like concat('%', #{note}, '%')

    </select>

mapper:

public List<Role> findRolesByMap(Map<String, Object> parameterMap);

test:

public static void testFindRolesByMap() {

        SqlSession sqlSession = null;

        try {

            sqlSession = SqlSessionFactoryUtils.openSqlSession();

            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);

            Map<String, Object> parameterMap = new HashMap<String, Object>();

            parameterMap.put("roleName", "1");

            parameterMap.put("note", "1");

            List<Role> roles = roleMapper.findRolesByMap(parameterMap);

            System.out.println(roles.size());

        } catch(Exception ex) {

            ex.printStackTrace();

        } finally {

            if (sqlSession != null) {

                sqlSession.close();

            }

        }

    }

case 3: 注解：

xml:

<select id="findRolesByAnnotation" resultType="role">

        select id,

        role_name as roleName, note from t_role

        where role_name like

        concat('%', #{roleName}, '%')

        and note like concat('%', #{note}, '%')

</select>

mapper:

public List<Role> findRolesByAnnotation(@Param("roleName") String rolename, @Param("note") String note);

test:

public static void testFindRolesByAnnotation() {

        SqlSession sqlSession = null;

        try {

            sqlSession = SqlSessionFactoryUtils.openSqlSession();

            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);

            List<Role> roles = roleMapper.findRolesByAnnotation("1", "1");

            System.out.println(roles.size());

        } catch(Exception ex) {

            ex.printStackTrace();

        } finally {

            if (sqlSession != null) {

                sqlSession.close();

            }

        }

    }

case 4: java bean:

java bean:

public class RoleParams {

    private String roleName;

    private String note;

    public String getRoleName() {

        return roleName;

    }

    public void setRoleName(String roleName) {

        this.roleName = roleName;

    }

    public String getNote() {

        return note;

    }

    public void setNote(String note) {

        this.note = note;

    }

}

xml:

<select id="findRolesByBean" parameterType="com.ssm.chapter5.param.RoleParams"

        resultType="role">

        select id, role_name as roleName, note from t_role

        where

        role_name like

        concat('%', #{roleName}, '%')

        and note like concat('%',

        #{note}, '%')

</select>

mapper:

public List<Role> findRolesByBean(RoleParams roleParam);

test

public static void testFindRolesByBean() {

        SqlSession sqlSession = null;

        try {

            sqlSession = SqlSessionFactoryUtils.openSqlSession();

            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);

            RoleParams roleParam = new RoleParams();

            roleParam.setNote("1");

            roleParam.setRoleName("1");

            List<Role> roles = roleMapper.findRolesByBean(roleParam);

            System.out.println(roles.size());

        } catch(Exception ex) {

            ex.printStackTrace();

        } finally {

            if (sqlSession != null) {

                sqlSession.close();

            }

        }

    }

case 5: 混合使用 bean 和注解

bean 2:

public class PageParams {

    private int start;

    private int limit;

    public int getStart() {

        return start;

    }

    public void setStart(int start) {

        this.start = start;

    }

    public int getLimit() {

        return limit;

    }

    public void setLimit(int limit) {

        this.limit = limit;

    }

}

xml:

<select id="findByMix" resultType="role">

        select id, role_name as

        roleName, note from t_role

        where role_name like

        concat('%',

        #{params.roleName}, '%')

        and note like concat('%', #{params.note}, '%')

        limit #{page.start}, #{page.limit}

    </select>

mapper:

public List<Role> findByMix(@Param("params") RoleParams roleParams, @Param("page") PageParams PageParam);

test:

public static void testFindByMix() {

        SqlSession sqlSession = null;

        try {

            sqlSession = SqlSessionFactoryUtils.openSqlSession();

            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);

            RoleParams roleParam = new RoleParams();

            roleParam.setNote("1");

            roleParam.setRoleName("1");

            PageParams pageParams = new PageParams();

            pageParams.setStart(0);

            pageParams.setLimit(100);

            List<Role> roles = roleMapper.findByMix(roleParam, pageParams);

            System.out.println(roles.size());

        } catch(Exception ex) {

            ex.printStackTrace();

        } finally {

            if (sqlSession != null) {

                sqlSession.close();

            }

        }

    }

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Mybatis映射器(一)

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