今天在看JDBC4.2新规范，然后无意之间就碰到了这个东西QueryObjectFactor...
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？
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