第一章回顾jdbc开发
1）优点：简单易学,上手快,非常灵活构建SQL，效率高
2）缺点：代码繁琐，难以写出高质量的代码（例如：资源的释放，SQL注入安全性等）
开发者既要写业务逻辑，又要写对象的创建和销毁，必须管底层具体数据库的语法
（例如：分页）。
3）适合于超大批量数据的操作，速度快
第二章回顾hibernate单表开发
1）优点：不用写SQL，完全以面向对象的方式设计和访问，不用管底层具体数据库的语法，（例如：分页）便于理解。
2）缺点：处理复杂业务时，灵活度差, 复杂的HQL难写难理解，例如多表查询的HQL语句
3）适合于中小批量数据的操作，速度慢
第三章什么是mybatis，mybatis有什么特点
1）基于上述二种支持，我们需要在中间找到一个平衡点呢？结合它们的优点，摒弃它们的缺点，
这就是myBatis，现今myBatis被广泛的企业所采用。
2）MyBatis 本是apache的一个开源项目iBatis, 2010年这个项目由apache software foundation 迁移到了google code，并且改名为MyBatis 。2013年11月迁移到Github。
3）iBATIS一词来源于“internet”和“abatis”的组合，是一个基于Java的持久层框架。iBATIS提供的持久层框架包括SQL Maps和Data Access Objects（DAO）
4）jdbc/dbutils/springdao，hibernate/springorm，mybaits同属于ORM解决方案之一
第四章 mybatis快速入门
1）创建一个mybatis-day01这么一个javaweb工程或java工程
2）导入mybatis和mysql/oracle的jar包到/WEB-INF/lib目录下
3）创建students.sql表
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--mysql语法 create table students( id int(5) primary key, name varchar(10), sal double(8,2) ); --oracle语法 create table students( id number(5) primary key, name varchar2(10), sal number(8,2) ); |
4）创建Student.java
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/** * 学生 * @author AdminTC */ public class Student { private Integer id; private String name; private Double sal; public Student(){} public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Double getSal() { return sal; } public void setSal(Double sal) { this.sal = sal; } } |
5）在entity目录下创建StudentMapper.xml配置文件
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <insert id="add1"> insert into students(id,name,sal) values(1,'哈哈',7000) </insert> <insert id="add2" parameterType="cn.itcast.javaee.mybatis.app05.Student"> insert into students(id,name,sal) values(#{id},#{name},#{sal}) </insert> </mapper> |
6）在src目录下创建mybatis.xml配置文件
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<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis"/> <property name="username" value="root"/> <property name="password" value="root"/> </dataSource> </environment> </environments> <mappers> <mapper resource="cn/itcast/javaee/mybatis/app05/StudentMapper.xml"/> </mappers> </configuration> |
7）在util目录下创建MyBatisUtil.java类，并测试与数据库是否能连接
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/** * MyBatis工具类 * @author AdminTC */ public class MyBatisUtil { private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>(); private static SqlSessionFactory sqlSessionFactory; static{ try { Reader reader = Resources.getResourceAsReader("mybatis.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException(e); } } private MyBatisUtil(){} public static SqlSession getSqlSession(){ SqlSession sqlSession = threadLocal.get(); if(sqlSession == null){ sqlSession = sqlSessionFactory.openSession(); threadLocal.set(sqlSession); } return sqlSession; } public static void closeSqlSession(){ SqlSession sqlSession = threadLocal.get(); if(sqlSession != null){ sqlSession.close(); threadLocal.remove(); } } public static void main(String[] args) { Connection conn = MyBatisUtil.getSqlSession().getConnection(); System.out.println(conn!=null?"连接成功":"连接失败"); } } |
8）在dao目录下创建StudentDao.java类并测试
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/** * 持久层 * @author AdminTC */ public class StudentDao { /** * 增加学生（无参） */ public void add1() throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.insert("mynamespace.add1"); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); } MyBatisUtil.closeSqlSession(); } /** * 增加学生（有参） */ public void add2(Student student) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.insert("mynamespace.add2",student); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); } MyBatisUtil.closeSqlSession(); } public static void main(String[] args) throws Exception{ StudentDao dao = new StudentDao(); dao.add1(); dao.add2(new Student(2,"呵呵",8000D)); } } |
第五章 mybatis工作流程
1）通过Reader对象读取src目录下的mybatis.xml配置文件(该文本的位置和名字可任意)
2）通过SqlSessionFactoryBuilder对象创建SqlSessionFactory对象
3）从当前线程中获取SqlSession对象
4）事务开始，在mybatis中默认
5）通过SqlSession对象读取StudentMapper.xml映射文件中的操作编号，从而读取sql语句
6）事务提交，必写
7）关闭SqlSession对象，并且分开当前线程与SqlSession对象，让GC尽早回收
第六章 mybatis配置文件祥解（mybatis.xml）
1）以下是StudentMapper.xml文件，提倡放在与实体同目录下，文件名任意
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <insert id="add1"> insert into students(id,name,sal) values(1,'哈哈',7000) </insert> <insert id="add2" parameterType="cn.itcast.javaee.mybatis.app05.Student"> insert into students(id,name,sal) values(#{id},#{name},#{sal}) </insert> </mapper> |
第七章 mybatis映射文件祥解(StudentMapper.xml)
1）以下是mybatis.xml文件，提倡放在src目录下，文件名任意
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<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis"/> <property name="username" value="root"/> <property name="password" value="root"/> </dataSource> </environment> </environments> <mappers> <mapper resource="cn/itcast/javaee/mybatis/app05/StudentMapper.xml"/> </mappers> </configuration> |
第八章MybatisUtil工具类的作用
1）在静态初始化块中加载mybatis配置文件和StudentMapper.xml文件一次
2）使用ThreadLocal对象让当前线程与SqlSession对象绑定在一起
3）获取当前线程中的SqlSession对象，如果没有的话，从SqlSessionFactory对象中获取SqlSession对象
4）获取当前线程中的SqlSession对象，再将其关闭，释放其占用的资源
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/** * MyBatis工具类 * @author AdminTC */ public class MyBatisUtil { private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>(); private static SqlSessionFactory sqlSessionFactory; static{ try { Reader reader = Resources.getResourceAsReader("mybatis.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException(e); } } private MyBatisUtil(){} public static SqlSession getSqlSession(){ SqlSession sqlSession = threadLocal.get(); if(sqlSession == null){ sqlSession = sqlSessionFactory.openSession(); threadLocal.set(sqlSession); } return sqlSession; } public static void closeSqlSession(){ SqlSession sqlSession = threadLocal.get(); if(sqlSession != null){ sqlSession.close(); threadLocal.remove(); } } public static void main(String[] args) { Connection conn = MyBatisUtil.getSqlSession().getConnection(); System.out.println(conn!=null?"连接成功":"连接失败"); } } |
第九章基于MybatisUtil工具类，完成CURD操作
1）StudentDao.java
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/** * 持久层 * @author AdminTC */ public class StudentDao { /** * 增加学生 */ public void add(Student student) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.insert("mynamespace.add",student); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } /** * 修改学生 */ public void update(Student student) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.update("mynamespace.update",student); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } /** * 查询单个学生 */ public Student findById(int id) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ Student student = sqlSession.selectOne("mynamespace.findById",id); return student; }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } /** * 查询多个学生 */ public List<Student> findAll() throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ return sqlSession.selectList("mynamespace.findAll"); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } /** * 删除学生 */ public void delete(Student student) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.delete("mynamespace.delete",student); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } |
2）StudentMapper.xml
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <insert id="add" parameterType="cn.itcast.javaee.mybatis.app09.Student"> insert into students(id,name,sal) values(#{id},#{name},#{sal}) </insert> <update id="update" parameterType="cn.itcast.javaee.mybatis.app09.Student"> update students set name=#{name},sal=#{sal} where id=#{id} </update> <select id="findById" parameterType="int" resultType="cn.itcast.javaee.mybatis.app09.Student"> select id,name,sal from students where id=#{anything} </select> <select id="findAll" resultType="cn.itcast.javaee.mybatis.app09.Student"> select id,name,sal from students </select> <delete id="delete" parameterType="cn.itcast.javaee.mybatis.app09.Student"> delete from students where id=#{id} </delete> </mapper> |
第十章分页查询
1）StudentDao.java
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/** * 持久层 * @author AdminTC */ public class StudentDao { /** * 增加学生 */ public void add(Student student) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.insert("mynamespace.add",student); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } /** * 无条件分页查询学生 */ public List<Student> findAllWithFy(int start,int size) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ Map<String,Integer> map = new LinkedHashMap<String,Integer>(); map.put("pstart",start); map.put("psize",size); return sqlSession.selectList("mynamespace.findAllWithFy",map); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } /** * 有条件分页查询学生 */ public List<Student> findAllByNameWithFy(String name,int start,int size) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ Map<String,Object> map = new LinkedHashMap<String,Object>(); map.put("pname","%"+name+"%"); map.put("pstart",start); map.put("psize",size); return sqlSession.selectList("mynamespace.findAllByNameWithFy",map); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } public static void main(String[] args) throws Exception{ StudentDao dao = new StudentDao(); System.out.println("-----------Page1"); for(Student s:dao.findAllByNameWithFy("哈",0,3)){ System.out.println(s.getId()+":"+s.getName()+":"+s.getSal()); } System.out.println("-----------Page2"); for(Student s:dao.findAllByNameWithFy("哈",3,3)){ System.out.println(s.getId()+":"+s.getName()+":"+s.getSal()); } System.out.println("-----------Page3"); for(Student s:dao.findAllByNameWithFy("哈",6,3)){ System.out.println(s.getId()+":"+s.getName()+":"+s.getSal()); } System.out.println("-----------Page4"); for(Student s:dao.findAllByNameWithFy("哈",9,3)){ System.out.println(s.getId()+":"+s.getName()+":"+s.getSal()); } } } |
2）StudentMapper.xml
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <insert id="add" parameterType="cn.itcast.javaee.mybatis.app10.Student"> insert into students(id,name,sal) values(#{id},#{name},#{sal}) </insert> <select id="findAllWithFy" parameterType="map" resultType="cn.itcast.javaee.mybatis.app10.Student"> select id,name,sal from students limit #{pstart},#{psize} </select> <select id="findAllByNameWithFy" parameterType="map" resultType="cn.itcast.javaee.mybatis.app10.Student"> select id,name,sal from students where name like #{pname} limit #{pstart},#{psize} </select> </mapper> |
思考：oracle分页如何做呢？
第十一章动态SQL操作之查询
1） 查询条件不确定，需要根据情况产生SQL语法，这种情况叫动态SQL
2） 参见<<动态SQL—查询.JPG>>
StudentDao.java
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/** * 持久层 * @author AdminTC */ public class StudentDao { /** * 动态SQL--查询 */ public List<Student> dynaSQLwithSelect(String name,Double sal) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ Map<String,Object> map = new LinkedHashMap<String, Object>(); map.put("pname",name); map.put("psal",sal); return sqlSession.selectList("mynamespace.dynaSQLwithSelect",map); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } public static void main(String[] args) throws Exception{ StudentDao dao = new StudentDao(); List<Student> studentList1 = dao.dynaSQLwithSelect("哈哈",null); for(Student student : studentList1){ System.out.println(student.getId()+":"+student.getName()+":"+student.getSal()); } System.out.println("--------------"); List<Student> studentList2 = dao.dynaSQLwithSelect(null,7000D); for(Student student : studentList2){ System.out.println(student.getId()+":"+student.getName()+":"+student.getSal()); } System.out.println("--------------"); List<Student> studentList3 = dao.dynaSQLwithSelect("哈哈",7000D); for(Student student : studentList3){ System.out.println(student.getId()+":"+student.getName()+":"+student.getSal()); } System.out.println("--------------"); List<Student> studentList4 = dao.dynaSQLwithSelect(null,null); for(Student student : studentList4){ System.out.println(student.getId()+":"+student.getName()+":"+student.getSal()); } System.out.println("--------------"); } } |
StudentMapper.xml
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <select id="dynaSQLwithSelect" parameterType="map" resultType="cn.itcast.javaee.mybatis.app11.Student"> select id,name,sal from students <where> <if test="pname!=null"> and name=#{pname} </if> <if test="psal!=null"> and sal=#{psal} </if> </where> </select> </mapper> |
第十二章动态SQL操作之更新
1） 更新条件不确定，需要根据情况产生SQL语法，这种情况叫动态SQL
2） 参见<<动态SQL—更新.JPG>>
StudentDao.java
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/** * 持久层 * @author AdminTC */ public class StudentDao { /** * 动态SQL--更新 */ public void dynaSQLwithUpdate(Student student) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.update("mynamespace.dynaSQLwithUpdate",student); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } public static void main(String[] args) throws Exception{ StudentDao dao = new StudentDao(); dao.dynaSQLwithUpdate(new Student(10,null,5000D)); dao.dynaSQLwithUpdate(new Student(10,"哈哈",null)); dao.dynaSQLwithUpdate(new Student(10,"哈哈",6000D)); } } |
StudentMapper.xml
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <update id="dynaSQLwithUpdate" parameterType="cn.itcast.javaee.mybatis.app12.Student"> update students <set> <if test="name!=null"> name=#{name}, </if> <if test="sal!=null"> sal=#{sal}, </if> </set> where id=#{id} </update> </mapper> |
第十三章动态SQL操作之删除
1） 根据ID删除学生
2） 参见<<动态SQL—删除.JPG>>
StudentDao.java
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/** * 持久层 * @author AdminTC */ public class StudentDao { /** * 动态SQL--删除 */ public void dynaSQLwithDelete(int... ids) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.delete("mynamespace.dynaSQLwithDelete",ids); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } public static void main(String[] args) throws Exception{ StudentDao dao = new StudentDao(); dao.dynaSQLwithDelete(1,3,5,7); } } |
StudentMapper.xml
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <!-- item表示迭代的参数 --> <delete id="dynaSQLwithDelete"> delete from students where id in <!-- <foreach collection="array" open="(" close=")" separator="," item="ids"> ${ids} </foreach> --> <foreach collection="list" open="(" close=")" separator="," item="ids"> ${ids} </foreach> </delete> </mapper> |
第十四章动态SQL操作之插入
1） 根据条件，插入一个学生
2）参见<<动态SQL—插入.JPG>>
StudentDao.java
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/** * 持久层 * @author AdminTC */ public class StudentDao { /** * 动态SQL--插入 */ public void dynaSQLwithInsert(Student student) throws Exception{ SqlSession sqlSession = MyBatisUtil.getSqlSession(); try{ sqlSession.insert("mynamespace.dynaSQLwithInsert",student); }catch(Exception e){ e.printStackTrace(); sqlSession.rollback(); throw e; }finally{ sqlSession.commit(); MyBatisUtil.closeSqlSession(); } } public static void main(String[] args) throws Exception{ StudentDao dao = new StudentDao(); dao.dynaSQLwithInsert(new Student(1,"哈哈",7000D)); dao.dynaSQLwithInsert(new Student(2,"哈哈",null)); dao.dynaSQLwithInsert(new Student(3,null,7000D)); } } |
StudentMapper.xml
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<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="mynamespace"> <sql id="key"> <trim suffixOverrides=","> <if test="id!=null"> id, </if> <if test="name!=null"> name, </if> <if test="sal!=null"> sal, </if> </trim> </sql> <sql id="value"> <trim suffixOverrides=","> <if test="id!=null"> #{id}, </if> <if test="name!=null"> #{name}, </if> <if test="sal!=null"> #{sal}, </if> </trim> </sql> <insert id="dynaSQLwithInsert" parameterType="cn.itcast.javaee.mybatis.app14.Student"> insert into students(<include refid="key"/>) values(<include refid="value"/>) </insert> </mapper> |
第十五章jsp/js/jquery/easyui/json + @springmvc + spring + mybatis + oracle开发
【员工管理系统--增加员工】