1.新建项目，添加mybatis和mysql的jar包
2.在mysql中新建表user[id,name,age]
CREATE TABLE `users` (`id` int(11) NOT NULL auto_increment,`NAME` varchar(50) default NULL,`age` int(11) default NULL,PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8
3.新建User类，与db的表对应
public class User {public User() {}public User(int id, String name, int age) {super();this.id = id;this.name = name;this.age = age;}private int id;private String name;private int age;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}@Overridepublic String toString() {return "User [id=" + id + ", name=" + name + ", age=" + age + "]";}}
4.在src目录下面新建mybatis的配置文件conf.xml
<?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><!-- development：开发模式work：工作模式--><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://localhost:3306/mybatis?autoReconnect=true&useUnicode=true&characterEncoding=utf8" /><property name="username" value="root" /><property name="password" value="root" /></dataSource></environment></environments></configuration>
5.新建userMapper.xml，添加数据库操作语句
<?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"> <!-- 为了使用mapper的标签，在此要在Window-Preference-Xml Catalog中配置mybatis-3-mapper.dtd，key=-//mybatis.org//DTD Mapper 3.0//EN--> <mapper namespace="com.mlxs.mybatis.test.userMapper"><select id="getUser" parameterType="int" resultType="com.mlxs.mybatis.test1.User">select * from users where id=#{id}</select><!-- 添加，参数是一个user对象 --><insert id="addUser" parameterType="com.mlxs.mybatis.test1.User">insert into users(name,age) values(#{name},#{age})</insert><!-- 更新，参数是一个user对象 --><insert id="updateUser" parameterType="com.mlxs.mybatis.test1.User">update users set name=#{name}, age=#{age} where id=#{id}</insert><!-- 添加，参数是一个user对象 --><insert id="deleteUser" parameterType="int">delete from users where id=#{id}</insert><!-- 返回一个list，resultType="包名+类名"：必须在类中有个无参的构造函数，不然会报错：java.lang.NoSuchMethodException: com.mlxs.mybatis.test1.User.<init>() Caused by: java.lang.NoSuchMethodException: com.mlxs.mybatis.test1.User.<init>()at java.lang.Class.getConstructor0(Class.java:2706)at java.lang.Class.getDeclaredConstructor(Class.java:1985)at org.apache.ibatis.reflection.factory.DefaultObjectFactory.instantiateClass(DefaultObjectFactory.java:57) --><select id="selectAllUsers" resultType="com.mlxs.mybatis.test1.User">select * from users</select> </mapper>
将mapper配置文件添加到mybatis的配置文件conf.xml的mappers标签中：
<!-- 在conf.xml文件中注册Mapper.xml文件和Mapper类 --><mappers><mapper resource="com/mlxs/mybatis/test1/userMapper.xml" /></mappers>
6.添加测试类，获取一个user的信息
import java.io.IOException; import java.io.InputStream; import java.io.Reader;import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder;public class _Test1SelectOne {public static void main(String[] args) throws IOException {//加载mybatis的xml文件（同时加载加载关联的映射文件）//1.使用类加载器加载mybatis的配置文件 // InputStream config = _Test1SelectOne.class.getClassLoader().getResourceAsStream("conf.xml");//2.使用mybatis的Resources类加载Reader config = Resources.getResourceAsReader("conf.xml");//创建sqlSessionFactorySqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(config);//创建sqlSession，执行mapper.xml中的sql语句SqlSession sqlSession = sessionFactory.openSession();//执行映射文件中的sql(namespace + select的id)String sql = "com.mlxs.mybatis.test.userMapper.getUser";User user = sqlSession.selectOne(sql, "1");//查询id=1//关闭session sqlSession.close();System.out.println(user);} }
7.结果
User [id=1, name=Tom, age=12]
8.测试 增删改查，导入junit包，添加测试类
import java.util.List;import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.junit.Test;import com.mlxs.mybatis.util.MyBatisUtil;public class _Test2UserCrud {@Testpublic void addUser(){SqlSessionFactory sessionFactory = MyBatisUtil.getSessionFactory();SqlSession sqlSession = sessionFactory.openSession();String statement = "com.mlxs.mybatis.test.userMapper.addUser";int count = sqlSession.insert(statement, new User(0, "add1", 10));sqlSession.commit();sqlSession.close();System.out.println("add count:"+count);}@Testpublic void updateUser(){SqlSessionFactory sessionFactory = MyBatisUtil.getSessionFactory();SqlSession sqlSession = sessionFactory.openSession();String statement = "com.mlxs.mybatis.test.userMapper.updateUser";int count = sqlSession.update(statement, new User(3, "update2", 100));sqlSession.commit();sqlSession.close();System.out.println("update count:"+count);}@Testpublic void delUser(){SqlSessionFactory sessionFactory = MyBatisUtil.getSessionFactory();boolean autoCommit = true;//自动提交，不需手动commitSqlSession sqlSession = sessionFactory.openSession(autoCommit);String statement = "com.mlxs.mybatis.test.userMapper.deleteUser";int count = sqlSession.delete(statement, 4);sqlSession.close();System.out.println("del count:"+count);}@Testpublic void selectAll(){SqlSessionFactory sessionFactory = MyBatisUtil.getSessionFactory();boolean autoCommit = true;//自动提交，不需手动commitSqlSession sqlSession = sessionFactory.openSession(autoCommit);String statement = "com.mlxs.mybatis.test.userMapper.selectAllUsers";List<User> userList = sqlSession.selectList(statement);sqlSession.close();System.out.println(userList);} }
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