简单的Mybatis程序
1.新建一个普通Maven项目,导入 mybatis、mysql、junit(用于测试)3个依赖
Mybatis
<dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>${mybatis-version}</version> </dependency>
Mysql
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>${mysql-version}</version> </dependency>
Junit
<dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>${junit-version}</version> </dependency>
2.编写一个mybatis工具类MybatisUtils,方便后续使用
package com.zy.utils; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import java.io.IOException; import java.io.InputStream; public class MybatisUtils { private static SqlSessionFactory sqlSessionFactory; static { try { String resource="mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } catch (IOException e) { e.printStackTrace(); } } public static SqlSession getSqlSessionFactory(){ return sqlSessionFactory.openSession(); } }
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <!--configuration核心配置文件--> <configuration> <typeAliases> <package name="com.zy.pojo"/> </typeAliases> <!--配置环境--> <environments default="mysql"> <environment id="mysql"> <!--JDBC事务管理--> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/testmybatis?useSSL=false&useUnicode=true&characterEncoding=UTF-8"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> </dataSource> </environment> </environments> <mappers> <mapper resource="mapper/UserMapper.xml"></mapper> </mappers> </configuration>
4.引入MySQL数据库 testmybatis,新建实体类 User
package com.zy.pojo; //实体类 public class User { private int id; private String name; private String pwd; 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 String getPwd() { return pwd; } public void setPwd(String pwd) { this.pwd = pwd; } public User() { } public User(int id, String name, String pwd) { this.id = id; this.name = name; this.pwd = pwd; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", pwd='" + pwd + '\'' + '}'; } }
5.UserMapper接口及其XML文件
UserMapper.java:
package com.zy.dao; import com.zy.pojo.User; import java.util.List; public interface UserMapper { List<User> getUserList(); }
UserMapper.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.zy.dao.UserMapper"> <select id="getUserList" resultType="com.zy.pojo.User"> select * from testmybatis.user </select> </mapper>
6.使用junit进行测试
package com.zy.dao; import com.zy.pojo.User; import com.zy.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.List; public class UserMapperTest { //获取sqkSession对象 SqlSession sqlSession = MybatisUtils.getSqlSessionFactory(); try { UserMapper mapper = sqlSession.getMapper(UserMapper.class); List<User> userList = mapper.getUserList(); for (User user : userList) { System.out.println(user); } } catch (Exception e) { e.printStackTrace(); } finally { //无论成功与否,都必须关闭 sqlSession.close(); } }
效果截图
7、简单的CRUD
UserMapper.java
List<User> getUserList(); int insertUser(User user); int updateUser(User user); int deleteUserById(int id);
其中 增改删 使用的是int类型,也可以使用void
但是为了方便判断操作是否成功(1成功,0失败),我更倾向于int
UserMapper.xml
<!--查--> <select id="getUserList" resultType="com.zy.pojo.User"> select * from testmybatis.user </select> <!--增--> <insert id="insertUser" parameterType="com.zy.pojo.User"> insert into testmybatis.user(id,name,pwd) values (#{id},#{name},#{pwd}) </insert> <!--改--> <update id="updateUser" parameterType="com.zy.pojo.User"> update testmybatis.user set name=#{name},pwd=#{pwd} where id=#{id} </update> <!--删--> <delete id="deleteUserById" parameterType="int"> delete from testmybatis.user where id=#{id} </delete>
最后使用测试类逐一测试即可