Mybatis小试CRUD

louyaoluan

　　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 configurationPUBLIC "-//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 mapperContactMapper mapper = session.getMapper(ContactMapper.class);return mapper;}private void closeSession(){if(session!=null){session.close();}}//query allpublic List<Contact> query(){ContactMapper mapper = getContactMapper();List<Contact> list = mapper.selectList();return list;}//query by namepublic List<Contact> query(String name) {ContactMapper mapper = getContactMapper();List<Contact> list = mapper.selectByName(name);return list;}//find one by idpublic Contact find(int id){ContactMapper mapper = getContactMapper();return mapper.findContact(id);}//update contactpublic int update(Contact contact){ContactMapper mapper = getContactMapper();transaction = DBUtil.getTransaction(session); //transactio beginint rows = mapper.updateContact(contact);try {transaction.commit(); //commit} catch (SQLException e) {e.printStackTrace();}finally{closeSession();}return rows; //return effected rows}//insert contact to dbpublic 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 idpublic 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 {@Testpublic 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());}}@Testpublic 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());}}@Testpublic 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());}@Testpublic 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);}@Testpublic 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);}@Testpublic 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。。。。