吐槽mybatis+熊猫哥优化教程

我将使用反射机制+自定义注解，该方法是由一个比我厉害的10倍的人教我的，感谢。百忙之中，水一篇 ，该文需要一定编程基础的人看

一，吐槽mybatis

我先吐槽这个动态条件sql，不知道mybatis那帮人为什么不能优化，可能是他们看这样的代码习惯了。反正我看到下面的代码，就感觉在看一堆shit，不仅辣眼睛，维护起来也是相当操蛋，是真的操蛋

        <if test="customer.email != null and customer.email !=''">
            AND a.email like "%"#{customer.email}"%"
        </if>
        <if test="customer.salesName != null and customer.salesName !=''">
            AND d.sales_name = #{customer.salesName}
        </if>
        <if test="customer.firstName != null and customer.firstName !=''">
            AND a.first_name like "%"#{customer.firstName}"%"
        </if>
        <if test="customer.lastName != null and customer.lastName !=''">
            AND a.last_name like "%"#{customer.lastName}"%"
        </if>
        <if test="customer.whatapp != null and customer.whatapp !=''">
            AND a.whatapp like "%"#{customer.whatapp}"%"
        </if>
        <if test="customer.country != null and customer.country !=''">
            AND a.country = #{customer.country}
        </if>
        <if test="customer.province != null and customer.province !=''">
            AND a.province like "%"#{customer.province}"%"
        </if>
        <if test="customer.orderCount != null and customer.orderCount !=''">
            AND a.order_count like "%"#{customer.orderCount}"%"
        </if>
        <if test="customer.orderAmount != null and customer.orderAmount !=''">
            AND a.order_amount = #{customer.orderAmount}
        </if>
        <if test="customer.levelId != null and customer.levelId !=''">
            AND a.level_id = #{customer.levelId}
        </if>
        <if test="customer.lastLoginDateStartDate != null">
            AND s.last_order_date <![CDATA[>= ]]> #{customer.lastLoginDateStartDate}
        </if>
        <if test="customer.lastLoginDateEndDate != null">
            AND s.last_order_date <![CDATA[< ]]> #{customer.lastLoginDateEndDate}
        </if>
        <if test="customer.lastOrderDateStartDate != null">
            AND s.last_login_date <![CDATA[>= ]]> #{customer.lastOrderDateStartDate}
        </if>
        <if test="customer.lastOrderDateEndDate != null">
            AND s.last_login_date <![CDATA[< ]]> #{customer.lastOrderDateEndDate}
        </if>

        <if test="customer.createAtStartDate != null">
            AND s.create_at <![CDATA[>= ]]> #{customer.createAtStartDate}
        </if>
        <if test="customer.createAtEndDate != null">
            AND s.create_at <![CDATA[< ]]> #{customer.createAtEndDate}
        </if>

二，优化

安静看代码，上面一堆shit一样的代码，我已经优化为下面这样，变量名a，是不是干净又清爽，维护起来也是相当简单

        <where>
            <foreach collection="conditionList" item="a" separator="and">
                    ${a}
            </foreach>
        </where>

熊猫哥优化教程

我将使用反射机制+自定义注解

第一：自定义注解annotation JewelryAlias

/**
 * @program:ant
 * @author:aodeng
 * @blog:低调小熊猫(https://aodeng.cc)
 * @微信公众号:低调小熊猫
 * @create:2019-06-04 18:41
 **/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface JewelryAlias {

    String value() default  "";

    String column() default  "";

    String type() default  "";
}

第二：封装工具：JewelryAnnotationUtil

/**
 * @author:aodeng(低调小熊猫)
 * @Description: TODO
 * @Date: 19-6-4
 **/
public class JewelryAnnotationUtil {

    private JewelryAnnotationUtil() {
    }

    public static List<String> getCondition(Object obj) throws IllegalAccessException {
        List<String> result = new ArrayList<>();
        System.out.println(obj.getClass()+"==============");
        Field[] fieldList = obj.getClass().getSuperclass().getDeclaredFields();
        for (Field field : obj.getClass().getDeclaredFields()) {
            field.setAccessible(true);
            if (field.isAnnotationPresent(JewelryAlias.class) && (field.get(obj) != null)) {
                JewelryAlias j = field.getAnnotation(JewelryAlias.class);
                StringBuilder s = new StringBuilder();
                s.append(!StrUtil.isBlank(j.value()) ? j.value().concat(".") : "");
                s.append(!StrUtil.isBlank(j.column()) ? j.column() : field.getName());
                switch (j.type()) {
                    case "=":
                        s.append(" = ");
                        if(field.getType().equals(String.class)){
                            s.append("'").append(field.get(obj)).append("'");
                        }else{
                            s.append(field.get(obj));
                        }
                        break;
                    case "like":
                        s.append(" like ");
                        if(field.getType().equals(String.class)){
                            s.append("'").append("%").append(field.get(obj)).append("%").append("'");
                        }else{
                            s.append("%").append(field.get(obj)).append("%");
                        }
                        break;
                    default:
                        break;
                }
                result.add(s.toString());
            }

        }
        return result;
    }
	
}

举个例子

controller：

    @RequestMapping(value = "/getOrderListByPage", method = RequestMethod.POST)
    public SuccessData getOrderListByPage(@RequestBody ConditionalQueryVo<SalesOrderQueryVo> queryVo) throws IllegalAccessException{
        if (ObjectUtil.isNull(queryVo.getConditionalObject())){
            queryVo.setConditionalObject(new SalesOrderQueryVo());
        }
        return CheckSqlStatus.getSuccessData(orderService.getOrderListByPage(JewelryAnnotationUtil.getCondition(queryVo.getConditionalObject()), queryVo.getPageIndex(), queryVo.getPageSize()));
    }

model：

/**
 * @author:aodeng(低调小熊猫)
 * @Description: TODO
 * @Date: 19-6-4
 **/
@Data
public class SalesOrderQueryVo {

    @JewelryAlias(value = "sot", column = "carrier_code", type = "=")
    private String carrierCode;

   @JewelryAlias(value = "sot", column = "track_number", type = "like")
    private String trackNumber;

    @JewelryAlias(value = "so", column = "order_increment", type = "like")
    private String orderIncrement;

    @JewelryAlias(value = "sot", column = "status", type = "=")
    private Integer status;
}

mapper：

List<SalesOrderModel> getOrderListByPage(Page<Object> page,@Param("conditionList") List<String> conditionList);

𝓜𝔂 𝓵𝓲𝓷𝓴𝓼：