Mybatis配置并实现（XML方式）
Mybatis配置并实现（XML方式）
-
idea中创建一个maven项目
-
在pom文件中导入下面的依赖
<!--mybatis核心包--> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.6</version> </dependency> <!--mysql数据库驱动包--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.18</version> </dependency> <!--log4j日志包--> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> -
创建一个java源文件夹和resources资源文件夹并准备好mybatis配置文件mybaits.xml和数据库文件db.properties
mybaits.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>
<!--数据库参数文件-->
<properties resource="db.properties"></properties>
<!--别名的配置，可以不用-->
<typeAliases>
<package name="cn.cqy.domain"></package>
</typeAliases>
<!--配置环境，可以多个，这里要设置一个默认使用的环境-->
<environments default="dev">
<!--配置环境名，唯一一个id名称-->
<environment id="dev">
<!--事务管理 type:JDBC(支持事务)/MANAGED(什么都不做)-->
<transactionManager type="JDBC"></transactionManager>
<!--数据源, 连接池 type(POOLED):MyBatis自带的连接池-->
<dataSource type="POOLED">
<property name="driver" value="${driverClassName}"></property>
<property name="url" value="${url}"></property>
<property name="username" value="${username}"></property>
<property name="password" value="${password}"></property>
</dataSource>
</environment>
</environments>
<!--这个mappers代表的是相应的ORM映射文件 这里先准备好了-->
<mappers>
<mapper resource="cn/cqy/mapper/StudentMapper.xml"></mapper>
</mappers>
</configuration>
db.properties
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/prc?userUnicode=true&characterEncoding=utf8&serverTimezone=UTC
username=root
password=root
-
数据库准备，略。
-
准备相应的对象
创建一个Student对象，和数据库的表对应
public class Student { private String s_id; private String s_name; private String s_birth; private String s_sex; public Student() {} //getter,setter 方法省略 ｝ -
mapper的准备 ，创建一个mapper文件夹，并在内创建一个StudentMapper接口
public interface StudentMapper { //查找学生表全部信息 public List<Student> selectAll(); //根据姓名查找学生 public Student selectByName(String name); //插入一条学生信息 public void insertOne(Student stu); //根据姓名删除一条学生信息 public void deleteByName(String name); //根据姓名修改一条学生信息 public void updateByName(Student stu); } -
在resoures资源文件夹下创建和mapper文件夹路径相同的文件夹
然后创建映射文件StudentMapper.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"> <!--命名空间 必须和所对应接口的全限定名一致--> <mapper namespace="cn.cqy.mapper.StudentMapper"> <!--定义sql的标签的id，需要和对应接口的方法名一致 resultType的类型在没有配置别名的情况下，应该是POJO类的全限定名 如cn.cqy.domain.Student--> <select id="selectAll" resultType="Student"> SELECT s_id,s_name,s_birth,s_sex FROM student </select> <!--参数类型为自定类型没有别名，输入类型全限定名，为Java类型时输入其对应映射名 如 long:大Long _long:小long (具体的对应请参见文档)--> <select id="selectByName" resultType="Student" parameterType="String"> SELECT s_id,s_name,s_birth,s_sex FROM student WHERE s_name = #{name} </select> <insert id="insertOne" parameterType="Student"> INSERT INTO student (s_id,s_name,s_birth,s_sex) VALUES (#{s_id},#{s_name},#{s_birth},#{s_sex}) </insert> <delete id="deleteByName" parameterType="String"> DELETE FROM student where s_name = #{s_name} </delete> <update id="updateByName" parameterType="Student" > UPDATE student SET s_birth = #{s_birth},s_sex = #{s_sex} WHERE s_name = #{s_name} </update> </mapper> -
抽取出一个MybatisUtil工具类
public class MybatisUtil { private static SqlSessionFactory sqlSessionFactory; //静态代码块：在使用的时候先执行，并且执行一次 static { try { InputStream is = Resources.getResourceAsStream("mybatis.xml"); SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); //创建一个工厂实例（加载了我们的配置文件） sqlSessionFactory = builder.build(is); } catch (IOException e) { e.printStackTrace(); } } /** *拿到了一个SqlSession对象 */ public static SqlSession getSqlSession() { return sqlSessionFactory.openSession(); } public static void closeSqlSession(SqlSession sqlSession) { if (sqlSession != null) { sqlSession.close(); } } } -
编写测试类
public class SqlTest { @Test public void testSelectAll() { //通过工具类获得SqlSession对象 SqlSession sqlSession = MybatisUtil.getSqlSession(); //获取到绑定到SqlSession的POJO类对应的映射 StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class); //通过映射调用查询方法 List<Student> students = studentMapper.selectAll(); //关闭SqlSession sqlSession.close(); for (Student student : students) { System.out.println(student); } } @Test public void testSelectByName() { SqlSession sqlSession = MybatisUtil.getSqlSession(); StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class); Student stu = studentMapper.selectByName("吴兰"); sqlSession.close(); System.out.println(stu); } @Test public void testInsertOne() { SqlSession sqlSession = MybatisUtil.getSqlSession(); StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class); Student stu = new Student(); stu.setS_id("09"); stu.setS_name("李水"); stu.setS_birth("1988-08-22"); stu.setS_sex("男"); studentMapper.insertOne(stu); //增、删、改需要提交事务，否则不会修改 sqlSession.commit(); sqlSession.close(); } @Test public void testDeleteByName() { SqlSession sqlSession = MybatisUtil.getSqlSession(); StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class); studentMapper.deleteByName("李水"); sqlSession.commit(); sqlSession.close(); } @Test public void testUpdateByName() { SqlSession sqlSession = MybatisUtil.getSqlSession(); StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class); Student stu = new Student(); stu.setS_name("李水"); stu.setS_birth("1999-01-22"); stu.setS_sex("女"); studentMapper.updateByName(stu); sqlSession.commit(); sqlSession.close(); } } -
测试查询结果
