Question

我在Play Framework 2.3.6 Java项目中使用MyBatis 3.2.8。我已经挣扎了几天，迭代遍历复杂对象参数中的MyBatis映射器的整数列表。这是我的设置：

我在EventFilter.java中有一个名为EventFilter的类：

public class EventFilter {
private String beginDate;
private String endDate;
private List<Integer> closestCountry;
private List<Integer> territorialWaterStatus;
private List<Integer> vesselCountry;
private String closestCountryInClause;
private String territorialWaterStatusInClause;
private String vesselCountryInClause;

public EventFilter() { }

public EventFilter(JsonNode jsonNode){
    this.beginDate = jsonNode.get("beginDate").asText();
    this.endDate = jsonNode.get("endDate").asText();
    this.closestCountry = JsonHelper.arrayNodeToIntegerList((ArrayNode) jsonNode.get("closestCountry"));
    this.territorialWaterStatus = JsonHelper.arrayNodeToIntegerList((ArrayNode) jsonNode.get("territorialWaterStatus"));
    this.vesselCountry = JsonHelper.arrayNodeToIntegerList((ArrayNode) jsonNode.get("vesselCountry"));
}

public String getBeginDate() {
    return beginDate;
}

public void setBeginDate(String beginDate) {
    this.beginDate = beginDate;
}

public String getEndDate() {
    return endDate;
}

public void setEndDate(String endDate) {
    this.endDate = endDate;
}

public List<Integer> getTerritorialWaterStatus() {
    if(this.territorialWaterStatus.size() > 0) {
        return territorialWaterStatus;
    } else {
        return null;
    }
}

public void setTerritorialWaterStatus(List<Integer> territorialWaterStatus) {
    this.territorialWaterStatus = territorialWaterStatus;
}

public List<Integer> getClosestCountry() {
    if(this.closestCountry.size() > 0) {
        return closestCountry;
    } else {
        return null;
    }
}

public void setClosestCountry(List<Integer> closestCountry) {
    this.closestCountry = closestCountry;
}

public List<Integer> getVesselCountry() {
    if(this.vesselCountry.size() > 0) {
        return vesselCountry;
    } else {
        return null;
    }
}

public void setVesselCountry(List<Integer> vesselCountry) {
    this.vesselCountry = vesselCountry;
}

}

这在我的mybatis配置文件中被引用为类型别名：

<configuration>

<typeAliases>
    <typeAlias type="models.Event" alias="Event"/>
    <typeAlias type="models.EventFilter" alias="EventFilter"/>
    <typeAlias type="models.Country" alias="Country"/>
</typeAliases>

<environments default="development">
    <environment id="development">
        <transactionManager type="JDBC"/>
        <dataSource type="POOLED">
            <property name="driver" value="org.postgresql.Driver"/>
            <property name="url" value="jdbc:postgresql://localhost:5432/mpmap"/>
            <property name="username" value="postgres"/>
            <property name="password" value="dbpw"/>
        </dataSource>
    </environment>
</environments>

<mappers>
    <mapper resource="EventMapper.xml"/>
</mappers>
</configuration>

我有一个mapper，它将EventFilter对象作为参数。然后应检查是否设置了beginDate，endDate，nearestCountry，vesselCountry和territorialWaterStatus。如果是，它将它们用于WHERE子句：

<select id="getEventsWithFilter" resultType="Event" resultMap="EventResult">
    SELECT ev.id, to_char(ev.occurred_on, 'YYYY-MM-DD') AS occurred_on_date,
        to_char(ev.occurred_on, 'HH24:MI:SS') AS occurred_on_time,
        ST_X(ev.location) AS longitude, ST_Y(ev.location) AS latitude,
        COALESCE(co01.name, 'Unspecified') AS closest_country,
        COALESCE(co02.name, 'Unspecified') AS territorial_water_status,
        COALESCE(co03.name, 'Unspecified') AS vessel_flag_country
    FROM event AS ev
    LEFT JOIN country AS co01
        ON co01.cow_id = ev.location_closest_country_id
    LEFT JOIN country AS co02
        ON co02.cow_id = ev.location_water_status_country_id
    LEFT JOIN country AS co03
        ON co03.cow_id = ev.vessel_flag_country_id
    <where>
        <if test="#{eventFilter.beginDate} != null and #{eventFilter.endDate} != null">
            ev.occurred_on &gt;= #{eventFilter.beginDate}::timestamp AND ev.occurred_on &lt;= #{eventFilter.endDate}::timestamp
        </if>
        <if test="#{eventFilter.closestCountry} != null">
            AND ev.location_closest_country_id IN
            <foreach item="id" index="index" collection="#{eventFilter.closestCountry}" open="(" separator="," close=")">
                #{id}
            </foreach>
        </if>
        <if test="#{eventFilter.territorialWaterStatus} != null">
            AND ev.location_water_status_country_id IN
            <foreach item="id" index="index" collection="#{eventFilter.territorialWaterStatus}" open="(" separator="," close=")">
                #{id}
            </foreach>
        </if>
        <if test="#{eventFilter.vesselCountry} != null">
            AND ev.vessel_flag_country_id IN
            <foreach item="id" index="index" collection="#{eventFilter.vesselCountry}" open="(" separator="," close=")">
                #{id}
            </foreach>
        </if>
    </where>
    ORDER BY ev.occurred_on ASC;
</select>

我将映射器链接到一个接口，如下所示：

    public List<Event> getEventsWithFilter(@Param("eventFilter") EventFilter eventFilter);

我用一个MybatisMapper助手类来调用它，它生成我的会话如下：

public static List<Event> getEvents(EventFilter eventFilter) {
    MybatisMapper mapper = new MybatisMapper();
    SqlSession session = mapper.getSession();
    EventMapper eventMapper = session.getMapper(EventMapper.class);

    List<Event> events;

    List<Integer> li = eventFilter.getClosestCountry();

    try {
        events = eventMapper.getEventsWithFilter(eventFilter);
    } finally {
        session.close();
    }

    return events;
}

问题：

beginDate和endDate自行完成。但是我对整数列表有以下问题：

检查列表是否为null的if语句似乎正在获取忽略，或当它应该是假时评估为true。
整数列表似乎作为null传递给IN子句。
如果我注释掉整数列表IN子句，并且只是为了beginDate和 endDate，它完全正常。但是，如果我留下整数列表IN子句，查询不会失败，但它返回一个空设置，好像要说“WHERE列IN（）”。

这是执行映射器/查询时由Play和Mybatis打印的控制台日志记录，以及EventFilter打印其内容。它们有点冗长所以我把它们放在pastebin中：

当我为三个整数列表中的每一个传递三个国家/地区时：http://pastebin.com/aWcXyikh
当我只传递beginDate和endDate时：http://pastebin.com/CeCv256g

这比我想要的要长一点，但要提前感谢任何帮助或建议。

Answer 1

我终于开始工作了。我最不得不改变的是在我的XML映射器中寻址参数列表而没有周围的花括号。

所以而不是：

 <if test="#{eventFilter.closestCountry} != null">
        AND ev.location_closest_country_id IN
        <foreach item="id" index="index" collection="#{eventFilter.closestCountry}" open="(" separator="," close=")">
            #{id}
        </foreach>
    </if>

应该是：

<if test="eventFilter.closestCountry != null">
            AND ev.location_closest_country_id IN
            <foreach item="id" index="index" collection="eventFilter.closestCountry" open="(" separator="," close=")">
                #{id}
            </foreach>
        </if>

这很奇怪，因为传递对象中的寻址字符串可以使用任何一种方法 - 即＃{eventFilter.beginDate}与eventFilter.beginDate相同。

一个非常微妙的区别，但我希望它可以帮助别人节省一些时间。

Answer 2

试试这个

<if test="eventFilter.closestCountry != null">
        AND ev.location_closest_country_id IN
        <foreach item="id" index="index" collection="eventFilter.closestCountry" open="(" separator="," close=")">
            ${id}
        </foreach>
    </if>

Answer 3

我正在使用MyBatis v。3.4.6。

我的情况：

@Mapper
public interface CorsoMapper {
    List<CorsoEntity> elenco(Filtro filtro);
}


public class Filtro implements Serializable {
    private static final long serialVersionUID = -8357822764110641974L;

    private String codice;
    private List<String> codici;

    public String getCodice() {
        return codice;
    }

    public void setCodice(String codice) {
        this.codice = codice;
    }

    public List<String> getCodici() {
        return codici;
    }

    public void setCodici(List<String> codici) {
        this.codici = codici;
    }
}

SQL：

<select id="elencoCorsi" parameterType="it.blabla.Filtro" resultMap="corsoMap">
    AND CODICI IN
    <foreach item="c" collection="codici" open="(" separator="," close=")">
       #{c}
    </foreach>
</select>

它无需使用“ index”属性即可工作。

Mybatis对复杂对象参数中的整数列表进行迭代

3 个答案: