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(); } } }
原文地址:https://www.cnblogs.com/daxiong225/p/9902114.html