Mybatis小试CRUD

初次使用mybatis，对contacts表做一个增删改查。

contacts表结构：

+---------+------------------+
| Field | Type |
+---------+------------------+
| id | int(10) unsigned |
| name | varchar(45) |
| address | varchar(45) |
| gender | char(1) |
| dob | datetime |
| email | varchar(45) |
| mobile | varchar(15) |
| phone | varchar(15) |
+---------+------------------+

eclipse工程结构：

官方文档上直接copy了mybatis主配置文件，稍作修改，保存为configuration.xml 如下

<?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> <properties resource="db.properties"> </properties> <typeAliases> <typeAlias type="com.mybatistest.bean.Contact" alias="Contact"/> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="${driver}" /> <property name="url" value="${url}" /> <property name="username" value="${username}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <mappers> <mapper resource="com/mybatistest/bean/ContactMapper.xml" /> </mappers> </configuration>生成entity类 Contact.java ，并建立对应的ContactMapper.xml文件，如下：

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd"> <mapper namespace="com.mybatistest.mapper.ContactMapper"> <select id="selectList" resultType="Contact"> select * from contacts </select> <select id="selectByName" parameterType="String" resultType="Contact"> select * from contacts where name like concat('%',#{name},'%') </select> <select id="findContact" parameterType="int" resultType="Contact"> select * from contacts where id=#{id} </select> <update id="updateContact" parameterType="Contact"> update contacts set name=#{name},address=#{address},gender=#{gender}, dob=#{dob},email=#{email},mobile=#{mobile},phone=#{phone} where id=#{id} </update> <insert id="insertContact" parameterType="Contact" useGeneratedKeys="true" keyProperty="id"> insert into contacts (name,address,gender,dob,email,mobile,phone) values (#{name},#{address},#{gender},#{dob},#{email},#{mobile},#{phone}) </insert> <delete id="deleteContact" parameterType="int"> delete from contacts where id=#{id} </delete> </mapper>第一次写like查询的时候是用的 like '%#{name}%'，结果查不到，网上查过以后，有人给的建议是contact('%',#{name},'%')，于是拿来用了。

同时，还要生成一个ContactMapper的接口，如下：

public interface ContactMapper { List<Contact> selectList(); List<Contact> selectByName(String name); Contact findContact(int id); int updateContact(Contact contact); int insertContact(Contact contact); int deleteContact(int id); }

下面是CRUD操作的实现

public class ContactDaoImpl implements ContactDao { private SqlSession session; // private Transaction transaction; // private ContactMapper getContactMapper(){ session = DBUtil.getSqlSession(); //get mapper ContactMapper mapper = session.getMapper(ContactMapper.class); return mapper; } private void closeSession(){ if(session!=null){ session.close(); } } //query all public List<Contact> query(){ ContactMapper mapper = getContactMapper(); List<Contact> list = mapper.selectList(); return list; } //query by name public List<Contact> query(String name) { ContactMapper mapper = getContactMapper(); List<Contact> list = mapper.selectByName(name); return list; } //find one by id public Contact find(int id){ ContactMapper mapper = getContactMapper(); return mapper.findContact(id); } //update contact public int update(Contact contact){ ContactMapper mapper = getContactMapper(); transaction = DBUtil.getTransaction(session); //transactio begin int rows = mapper.updateContact(contact); try { transaction.commit(); //commit } catch (SQLException e) { e.printStackTrace(); }finally{ closeSession(); } return rows; //return effected rows } //insert contact to db public int insert(Contact contact){ ContactMapper mapper = getContactMapper(); transaction = DBUtil.getTransaction(session); int rows = mapper.insertContact(contact); try { transaction.commit(); } catch (SQLException e) { e.printStackTrace(); }finally{ closeSession(); } return rows; } //delete contact by id public int delete(int id){ ContactMapper mapper = getContactMapper(); transaction = DBUtil.getTransaction(session); int rows = mapper.deleteContact(id); try { transaction.commit(); } catch (SQLException e) { e.printStackTrace(); }finally{ closeSession(); } return rows; } }之后重构，生成接口ContactDao。

下面是工具类DBUtil.java

public class DBUtil { private static SqlSessionFactory sessfactory = null; private static TransactionFactory transFactory = null; static{ Reader reader = null; try { reader = Resources.getResourceAsReader("configuration.xml"); } catch (IOException e) { e.printStackTrace(); } sessfactory = new SqlSessionFactoryBuilder().build(reader); transFactory = new JdbcTransactionFactory(); } public static Transaction getTransaction(SqlSession session){ return transFactory.newTransaction(session.getConnection()); } public static SqlSession getSqlSession(){ return sessfactory.openSession(); } }写完实现了，接着可以写简单单元测试了。。

public class ContactDaoTest { @Test public void testSelectList(){ ContactDao dao = new ContactDaoImpl(); List<Contact> list = dao.query(); Assert.assertEquals(3, list.size()); for(Contact c : list){ System.out.println("name:"+c.getName()+",dob:"+c.getDob()+",email:"+c.getEmail()); } } @Test public void testSelectByName(){ ContactDao dao = new ContactDaoImpl(); List<Contact> list = dao.query("tangerine"); Assert.assertEquals(1, list.size()); for(Contact c : list){ System.out.println("name:"+c.getName()+",dob:"+c.getDob()+",email:"+c.getEmail()); } } @Test public void testFindContact(){ ContactDao dao = new ContactDaoImpl(); Contact contact = dao.find(9); Assert.assertNotNull(contact); Assert.assertEquals("ssss", contact.getName()); System.out.println("name:"+contact.getName()); } @Test public void testInsertContact(){ Contact contact = new Contact(); contact.setName("MyBatis Test"); contact.setAddress("Newyork City,Down town"); contact.setDob(new Date()); contact.setGender("M"); contact.setEmail("HelloBatis@gmail.com"); ContactDao dao = new ContactDaoImpl(); int rows = dao.insert(contact); System.out.println(rows+" rows effected!"); Assert.assertEquals(1, rows); } @Test public void testUpdateContact(){ Contact contact = new Contact(); contact.setId(9); contact.setName("MyBatis Update"); contact.setAddress("Shanghai,China"); contact.setDob(new Date()); contact.setGender("M"); contact.setEmail("mybatisworld@gmail.com"); ContactDao dao = new ContactDaoImpl(); dao.update(contact); } @Test public void testDeleteContact(){ ContactDao dao = new ContactDaoImpl(); try{ int rows = dao.delete(5); Assert.assertEquals(1, rows); Contact deleted = dao.find(5); Assert.assertNull(deleted); }catch(Exception ex){ Assert.fail(); } }
mybatis还是挺简单的，就是要记的规则多了， 技术学多了，脑袋里面全是规则。。。。