MyBatis是支持普通sql查詢、存儲過程和高級映射的持久層框架。
MyBatis消除了幾乎所有的JDBC代碼和參數的手工設置以及對結果集的檢索封裝。
MyBatis可以使用簡單的XML或註解用於配置和原始映射，將接口和Java的POJO(Plain Old Java Objects 普通的Java對象)映射成數據庫中的記錄。
每一個Mybatis應用程序都以一個sqlSessionFactory對象的實例為核心。
sqlSessionFactory對象的實例可以通過sqlSessionFactoryBuilder對象來獲得。 sqlSessionFactoryBuilder對象可以通過xml配置文件，或從以往使用管理中準備好的Configuration類實例中來構建sqlSessionFactory對象。
DataSource dataSource = BlogDataSourceFactory.getBlogDataSource();TransactionFactory transactionFactory = new JdbcTransactionFactory();//環境Environment environment = new Environment("development", transactionFactory, dataSource);Configuration configuration = new Configuration(environment);//映射器類configuration.addMapper(BlogMapper.class);SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);注意這種情況下配置是添加映射器類。映射器類是Java類，這些類包含SQL映射語句的註解從而避免了xml文件的依賴，但是xml映射仍然在大多數高級映射(比如：嵌套join映射)時需要。
出於這樣的原因，如果存在xml配置文件的話，MyBatis將會自動查找和加載一個對等的XML文件(這種情況下，基於類路徑下的BlogMapper.class類的類名，那麼BlogMapper.xml將會被加載即class 與XML在同一個文件目錄下。如果非，則需要手動配置加載xml)。
<?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="com.web.mapper.userMapper"> <!-- 可以解決model屬性名與數據表中column列名不一致問題jdbcType一定要大寫--> <resultMap type="User" id="UserMap"> <id property="id" column="id" javaType="int" jdbcType="INTEGER"/> <result property="name" column="username" javaType="string" jdbcType="VARCHAR"/> <result property="age" column="age" javaType="int" jdbcType="INTEGER"/> </resultMap> <!-- 注意這裡的result，如果column == property 則可以直接返回Java object。 如果屬性名與列名不一致，解決方法如下： 1. 使用resultMap; 2.返回hashmap ; 3.查詢語句使用別名--> <select id="getUser" parameterType="int" resultMap="UserMap"> select * from t_user where id=#{id} </select> <delete id="deleteUser" parameterType="int" > delete from t_user where id=#{id} </delete> <update id="updateUser" parameterType="User" > update t_user set username=#{name},age=#{age} where id=#{id} </update> <insert id="insertUser" parameterType="User" > insert into t_user(username,age) values(#{name},#{age}) </insert> <!-- model's attr(name) different from column(username), so the result use UserMap --> <select id="getUsers" resultMap="UserMap"> select * from t_user </select></mapper>註冊到mybatis.xml [當與spring結合時，將不需要這個配置文件]
mybatis的配置文件
<?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="jdbc.properties"/> <!-- 配置實體類的別名--> <typeAliases> <!-- <typeAlias type="com.web.model.User" alias="User"/> --> <package name="com.web.model"/> </typeAliases><!-- development : 開發模式work : 工作模式--> <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/web/mapper/userMapper.xml"/> <mapper resource="com/web/mapper/orderMapper.xml"/> <mapper/> </mappers></configuration>這裡使用xml文件獲取sqlSessionFactory和sqlSession。
public static SqlSessionFactory getFactory(){/* flow the src dir*/String resource = "mybatis.xml";/*MybatisUtils.class.getResourceAsStream(resource)----- it's wrong !!!! * please distinguish the two up and down * */InputStream inputStream = MybatisUtils.class.getClassLoader().getResourceAsStream(resource);SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream);return factory;}SqlSession session = factory.openSession(true);//默認手動提交；/* 兩種解決方式： 1.factory.opensession(true); 2.session.commit(); *//*use sql xml not annotation*/@Test public void testAdd(){SqlSession session = MybatisUtils.getFactory().openSession();String statement = "com.web.mapper.userMapper.insertUser";/*return the effect rows*/int insert= session.insert(statement, new User("tom5", 15));/*default is not auto commit*/session.commit(true);session.close();System.out.println("effect rows.."+insert);}@Test public void testSelect(){/*set auto commit ,which equals to the above*/SqlSession session = MybatisUtils.getFactory().openSession(true);String statement = "com.web.mapper.userMapper.getUser";/*return the effect rows*/User user = session.selectOne(statement, 3);System.out.println("effect rows.."+user);}@Test public void testUpdate(){SqlSession session = MybatisUtils.getFactory().openSession(true);String statement = "com.web.mapper.userMapper.updateUser";/*return the effect rows*/int update= session.update(statement, new User(3,"tom4", 13));System.out.println("effect rows.."+update);}@Test public void testDelete(){SqlSession session = MybatisUtils.getFactory().openSession();String statement = "com.web.mapper.userMapper.deleteUser";/*return the effect rows*/int delete= session.delete(statement, 6);/* commit by yourself*/session.commit();System.out.println("effect rows.."+delete);session.close();}@Test public void testGetUsers(){SqlSession session = MybatisUtils.getFactory().openSession();String statement = "com.web.mapper.userMapper.getUsers";/*return the List<User>*/List<User> users= session.selectList(statement);session.commit();System.out.println("effect rows.."+users);session.close();}parameterType 和resultType 為hashmap ：
<select id="getUserForMap" parameterType="hashmap" resultType="hashmap"> select * from c_user where id=#{id}; </select> @Test public void getUserForMap(){SqlSession session = MybatisUtils.getFactory().openSession();String statement = "com.web.mapper.userMapper.getUserForMap";HashMap<String, Object> map = new HashMap<String, Object>();map.put("id", 1);/*return the effect rows*/Object selectOne = session.selectOne(statement, map);/*default is not auto commit*/session.commit(true);session.close();System.out.println("effect rows.."+selectOne+" ,class :"+selectOne.getClass());} effect rows..{id=1, age=12, name=luli} ,class :class java.util.HashMap綜上可知：mybatis 會根據參數類型和結果類型，自動進行解析封裝。
<select id="getListPage" parameterType="hashmap" resultMap="siteExtendDaoMap"> select id,site_id,site_name,site_number,province,city,area,address,internal_number,longitude,latitude from tb_site --使用動態sql <trim prefix="where" prefixOverrides="AND |OR "> <if test="checkState!= null and checkState!=''"> and check_state = #{checkState,jdbcType=INTEGER} </if> <if test="siteId!= null and siteId!=''"> and site_id like concat('%',#{siteId},'%') </if> <if test="siteName!= null and siteName!=''"> and site_name like concat('%',#{siteName},'%') </if> <if test="siteNumber!= null and siteNumber!=''"> and site_number like concat('%', #{siteNumber},'%') </if> <if test="province!= null and province!=''"> and province = #{province} </if> <if test="city!= null and city!=''"> and city = #{city} </if> <if test="area!= null and area!=''"> and area = #{area} </if> </trim> --添加排序<if test="sortname!= null and sortname!='' and sortorder!= null and sortorder!=''"> order by ${sortname} ${sortorder} </if> --添加分頁limit ${(page-1)*pagesize},${pagesize} </select>如果參數為pojo,mybatis會自動從對象裡面獲取id ;
<delete id="delete" parameterType="User"> delete from tb_user where id = #{id} </delete> <delete id="deleteById" parameterType="long"> delete from tb_user where id = #{id} </delete> <delete id="deleteByIds"> delete from tb_user where id in --使用foreach <foreach collection="list" item="id" open="(" separator=","close=")"> #{id} </foreach> </delete>通常與getListPage聯合使用。
<select id="getRows" parameterType="hashmap" resultType="long"> select count(*) from tb_sys_role <if test="keySysRole!= null"> <trim prefix="WHERE" prefixOverrides="AND |OR "> <if test="keySysRole.id!= null"> and id = #{keySysRole.id} </if> <if test="keySysRole.name!= null and keySysRole.name!=''"> and name = #{keySysRole.name} </if> <if test="keySysRole.available!= null and keySysRole.available!=''"> and available = #{keySysRole.available} </if> </trim> </if> </select>以上就是本文關於mybatis使用xml進行增刪改查代碼解析的全部內容，希望對大家有所幫助。感興趣的朋友可以繼續參閱本站其他相關專題，如有不足之處，歡迎留言指出。感謝朋友們對本站的支持！