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();
}
}
}
