mybatis 注解开发

数据库表

---

id为自增

id name state 1 杭州 浙江 2 苏州 江苏 3 南京 江苏

City实体类

---

public class City2 {    private Integer id;    private String cityName;    private String cityState;    public City2() {    }    public City2(String cityName, String cityState) {        this.cityName = cityName;        this.cityState = cityState;    }    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public String getCityName() {        return cityName;    }    public void setCityName(String cityName) {        this.cityName = cityName;    }    public String getCityState() {        return cityState;    }    public void setCityState(String cityState) {        this.cityState = cityState;    }    @Override    public String toString() {        return "City2{" + "id=" + id + ", cityName='" + cityName + '\'' + ", cityState='" + cityState + '\'' + '}';    }}

CityMapper

---

@Mapperpublic interface CityMapper {    @Select("select * from city where name=#{name}")    public City findByCountryname(@Param("name") String name);    @Select("select * from city")    public List<City> findAllCities();    @Insert("insert into city(name, state) values(#{name},#{state})")    public Integer insert(@Param("name") String name, @Param("state") String state);     /**     * 根据主键查询一个     *     * @param id     * @return     */    @Results(id = "cityResult", value = { @Result(property = "cityName", column = "name"),            @Result(property = "id", column = "id", id = true), @Result(property = "cityState", column = "state") })    @Select("select id, name, state from city where id=#{id}")    public City2 findCity2(@Param("id") Integer id);    /**     * 引用resultmap查询所有     * @return     */    @ResultMap("cityResult")    @Select("select id, name, state from city")    public List<City2> selectAll();    /**     * 批量删除数据     * @param ids     */    @Delete("<script> delete from city where id in "            + "<foreach collection=\"ids\" item=\"id\" open=\"(\" close=\")\" separator=\",\">" + "#{id}"            + "</foreach></script>")    public void deleteBatch(@Param("ids") List<Long> ids);    /**     * 批量插入数据     * @param cities     * @return     */    @Insert("<script>" + "insert into city (name, state) values "            + "<foreach collection=\"list\" item=\"city\" separator=\",\">" + "(#{city.cityName}, #{city.cityState})"            + "</foreach></script>")    public int insertBatch(List<City2> cities);}