Mybatis迷你版--QueryObjectFactory

　　今天在看JDBC4.2新规范，然后无意之间就碰到了这个东西QueryObjectFactory, 市面上orm框架有很多，在这里我就不一一列举了。那么今天我来记录一下QueryObjectFactory。官网地址：点这里

一、快速入门

1、将下载好的jar包加入项目

2、我们利用一下jdbc4.0的规范在项目中建立如下文件

在这里我们指定要加载的驱动：com.mysql.jdbc.Driver

3、编写接口：

package com.bdqn.lyrk.java.study;

import sf.qof.BaseQuery;

import sf.qof.Insert;

import sf.qof.Query;

import java.util.List;

public interface StudentDao extends BaseQuery {

    @Query(sql = "select stuName {%%.stuName},id {%%.id} from student_0")

    List<StudentEntity> listStudents();

    @Insert(sql = "INSERT INTO student_0 (id,stuName,password) values({%1.id},{%1.stuName},{%1.password})")

    void save(List<StudentEntity> studentEntities);

}

这里面我们使用注解的方式配置SQL语句。在这里{}表示占位符，{%%.属性} 通常用于设置查询结果对应的对象属性上，{%1} 通常代表方法内的参数

4、Main方法

package com.bdqn.lyrk.java.study;

import sf.qof.QueryObjectFactory;

import sf.qof.dialect.HSQLDbDialect;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

public class Main {

    public static void main(String[] args) throws SQLException {

        Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/MySchool?characterEncoding=utf-8&useSSL=false", "root", "xxx");

        StudentDao studentDao = QueryObjectFactory.createQueryObject(StudentDao.class);

        QueryObjectFactory.setSQLDialect(new HSQLDbDialect());

        studentDao.setConnection(connection);

        studentDao.setBatchSize(3);

        studentDao.listStudents().forEach(s -> System.out.println(s.getStuName()));

        List<StudentEntity> studentEntities = new ArrayList<>();

        for (int i = 0; i < 5; i++) {

            StudentEntity studentEntity = new StudentEntity();

            studentEntity.setId(i + 10);

            studentEntity.setStuName("test3");

            studentEntity.setPassword("abcd");

            studentEntities.add(studentEntity);

        }

        studentDao.save(studentEntities);

    }

}

执行成功后，拿到如下结果：

5、 设置参数的方式与坑

　　在这里面QueryFactory给我们设置了如下几种数据类型

registerResultMapper("string", AbstractCharacterMapping.StringMapping.class, AbstractCharacterMapping.StringMapping.getTypes());

    registerResultMapper("char", AbstractCharacterMapping.CharacterMapping.class, AbstractCharacterMapping.CharacterMapping.getTypes());

    registerResultMapper("boolean", AbstractNumberMapping.BooleanMapping.class, AbstractNumberMapping.BooleanMapping.getTypes());

    registerResultMapper("byte", AbstractNumberMapping.ByteMapping.class, AbstractNumberMapping.ByteMapping.getTypes());

    registerResultMapper("short", AbstractNumberMapping.ShortMapping.class, AbstractNumberMapping.ShortMapping.getTypes());

    registerResultMapper("int", AbstractNumberMapping.IntegerMapping.class, AbstractNumberMapping.IntegerMapping.getTypes());

    registerResultMapper("integer", AbstractNumberMapping.IntegerMapping.class, AbstractNumberMapping.IntegerMapping.getTypes());

    registerResultMapper("long", AbstractNumberMapping.LongMapping.class, AbstractNumberMapping.LongMapping.getTypes());

    registerResultMapper("float", AbstractNumberMapping.FloatMapping.class, AbstractNumberMapping.FloatMapping.getTypes());

    registerResultMapper("double", AbstractNumberMapping.DoubleMapping.class, AbstractNumberMapping.DoubleMapping.getTypes());

    registerResultMapper("date", AbstractDateTimeMapping.DateMapping.class, AbstractDateTimeMapping.DateMapping.getTypes());

    registerResultMapper("time", AbstractDateTimeMapping.TimeMapping.class, AbstractDateTimeMapping.TimeMapping.getTypes());

    registerResultMapper("timestamp", AbstractDateTimeMapping.TimestampMapping.class, AbstractDateTimeMapping.TimestampMapping.getTypes());

    registerParameterMapper("string", AbstractCharacterMapping.StringMapping.class, AbstractCharacterMapping.StringMapping.getTypes());

    registerParameterMapper("char", AbstractCharacterMapping.CharacterMapping.class, AbstractCharacterMapping.CharacterMapping.getTypes());

    registerParameterMapper("boolean", AbstractNumberMapping.BooleanMapping.class, AbstractNumberMapping.BooleanMapping.getTypes());

    registerParameterMapper("byte", AbstractNumberMapping.ByteMapping.class, AbstractNumberMapping.ByteMapping.getTypes());

    registerParameterMapper("short", AbstractNumberMapping.ShortMapping.class, AbstractNumberMapping.ShortMapping.getTypes());

    registerParameterMapper("int", AbstractNumberMapping.IntegerMapping.class, AbstractNumberMapping.IntegerMapping.getTypes());

    registerParameterMapper("integer", AbstractNumberMapping.IntegerMapping.class, AbstractNumberMapping.IntegerMapping.getTypes());

    registerParameterMapper("long", AbstractNumberMapping.LongMapping.class, AbstractNumberMapping.LongMapping.getTypes());

    registerParameterMapper("float", AbstractNumberMapping.FloatMapping.class, AbstractNumberMapping.FloatMapping.getTypes());

    registerParameterMapper("double", AbstractNumberMapping.DoubleMapping.class, AbstractNumberMapping.DoubleMapping.getTypes());

    registerParameterMapper("date", AbstractDateTimeMapping.DateMapping.class, AbstractDateTimeMapping.DateMapping.getTypes());

    registerParameterMapper("time", AbstractDateTimeMapping.TimeMapping.class, AbstractDateTimeMapping.TimeMapping.getTypes());

    registerParameterMapper("timestamp", AbstractDateTimeMapping.TimestampMapping.class, AbstractDateTimeMapping.TimestampMapping.getTypes());

　　注意我们通过以下几种方式设置数据类型：

　　{数据类型%1} 或者 {数据类型%%.属性的方式}

　　坑：注意以下关于日期数据类型代码：

/*

 * Copyright 2007 brunella ltd

 *

 * Licensed under the LGPL Version 3 (the "License");

 * you may not use this file except in compliance with the License.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

 * THE POSSIBILITY OF SUCH DAMAGE.

 */

package sf.qof.mapping;

import java.util.Date;

import java.util.HashSet;

import java.util.Set;

public abstract class AbstractDateTimeMapping extends AbstractBaseMapping implements Mapping, ParameterMapping,

    ResultMapping {

  private static final Set<Class<?>> types = new HashSet<Class<?>>();

  static {

    types.add(Date.class);

  }

  public static Set<Class<?>> getTypes() {

    return types;

  }

  public void accept(Mapper mapper, MappingVisitor visitor) {

    visitor.visit(mapper, this);

  }

  public abstract void accept(Mapper mapper, DateTimeMappingVisitor visitor);

  public static class DateMapping extends AbstractDateTimeMapping {

    public void accept(Mapper mapper, DateTimeMappingVisitor visitor) {

      visitor.visit(mapper, this);

    }

  }

  public static class TimeMapping extends AbstractDateTimeMapping {

    public void accept(Mapper mapper, DateTimeMappingVisitor visitor) {

      visitor.visit(mapper, this);

    }

  }

  public static class TimestampMapping extends AbstractDateTimeMapping {

    public void accept(Mapper mapper, DateTimeMappingVisitor visitor) {

      visitor.visit(mapper, this);

    }

  }

}

　　在静态代码块中所有的日期类型都对应的是java.util.Date ，因此我们不能用Timestamp或者java.sql.Date作为JavaBean的数据类型

二、总结与展望

1. 使用注解通常情况下适配一些比较简单的查询，复杂的查询不建议使用

2.这个适合于小型项目的迅速开发与上线，大型项目建议选择成熟的orm框架

3.虽然说select * 不建议使用的，但是如何解决select * 下映射关系？