Mybatis迷你版--QueryObjectFactory

　　今天在看JDBC4.2新規範，然後無意之間就碰到了這個東西QueryObjectFactory, 市面上orm架構有很多，在這裡我就不一一列舉了。那麼今天我來記錄一下QueryObjectFactory。官網位址： 點這裡

一、快速入門

1、将下載下傳好的jar包加入項目

2、我們利用一下jdbc4.0的規範在項目中建立如下檔案

在這裡我們指定要加載的驅動：com.mysql.jdbc.Driver

3、編寫接口：

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);


}      

View Code

這裡面我們使用注解的方式配置SQL語句。在這裡{}表示占位符，{%%.屬性} 通常用于設定查詢結果對應的對象屬性上，{%1} 通常代表方法内的參數

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);
    }
}      

執行成功後，拿到如下結果：

5、 設定參數的方式與坑

　　在這裡面QueryFactory給我們設定了如下幾種資料類型

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());      

　　注意我們通過以下幾種方式設定資料類型：

　　{資料類型%1} 或者 {資料類型%%.屬性的方式}

　　坑：注意以下關于日期資料類型代碼：

/*
 * 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);
    }
  }
}      

　　在靜态代碼塊中所有的日期類型都對應的是java.util.Date ，是以我們不能用Timestamp或者java.sql.Date作為JavaBean的資料類型

二、總結與展望

1. 使用注解通常情況下适配一些比較簡單的查詢，複雜的查詢不建議使用

2.這個适合于小型項目的迅速開發與上線，大型項目建議選擇成熟的orm架構

3.雖然說select * 不建議使用的，但是如何解決select * 下映射關系？