springboot整合mybatis 在不使用xml文件的情况下 做if判断

1. script标签

@Select({"<script>",
    "SELECT * FROM tbl_order",
    "WHERE 1=1",
    "<when test='title!=null'>",
    "AND mydate = #{mydate}",
    "</when>",
    "</script>"})
2、用Provider去实现SQL拼接，例如：

public class OrderProvider {
    private final String TBL_ORDER = "tbl_order";

    public String queryOrderByParam(OrderPara param) {
        SQL sql = new SQL().SELECT("*").FROM(TBL_ORDER);
        String room = param.getRoom();
        if (StringUtils.hasText(room)) {
            sql.WHERE("room LIKE #{room}");
        }
        Date myDate = param.getMyDate();
        if (myDate != null) {
            sql.WHERE("mydate LIKE #{mydate}");
        }
        return sql.toString();
    }
}

public interface OrderDAO {
    
    @SelectProvider(type = OrderProvider.class, method = "queryOrderByParam")
    List<Order> queryOrderByParam(OrderParam param);

}