标签：exist char ble 数据库表 map thread doc star 理解
MyBatis中文官网：
http://www.mybatis.cn/
我使用的工具是idea，jdk是1.8
1.创建一个maven项目 mbs_maven
2.引入mybatis的jar包
1 <dependency> 2 <groupId>mysql</groupId> 3 <artifactId>mysql-connector-java</artifactId> 4 <version>5.1.46</version> 5 </dependency> 6 7 <dependency> 8 <groupId>org.mybatis</groupId> 9 <artifactId>mybatis</artifactId> 10 <version>3.5.1</version> 11 </dependency>
3.引入log的jar包，mybatis是需要依赖log ，引入junit测试和lobok代码简化工具
1 <dependency> 2 <groupId>org.projectlombok</groupId> 3 <artifactId>lombok</artifactId> 4 <version>1.18.10</version> 5 </dependency> 6 7 <!-- log start --> 8 <dependency> 9 <groupId>org.slf4j</groupId> 10 <artifactId>slf4j-api</artifactId> 11 <version>${slf4j-api.version}</version> 12 </dependency> 13 <dependency> 14 <groupId>ch.qos.logback</groupId> 15 <artifactId>logback-core</artifactId> 16 <version>${logback.version}</version> 17 </dependency> 18 <dependency> 19 <groupId>ch.qos.logback</groupId> 20 <artifactId>logback-access</artifactId> 21 <version>${logback.version}</version> 22 </dependency> 23 <dependency> 24 <groupId>ch.qos.logback</groupId> 25 <artifactId>logback-classic</artifactId> 26 <version>${logback.version}</version> 27 </dependency> 28 <!-- log end --> 29 30 <dependency> 31 <groupId>junit</groupId> 32 <artifactId>junit</artifactId> 33 <version>4.12</version> 34 </dependency>
1 <properties> 2 <slf4j-api.version>1.7.25</slf4j-api.version> 3 <logback.version>1.1.7</logback.version> 4 </properties>
4.创建logback.xml
<?xml version="1.0" encoding="UTF-8"?> <configuration> <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> <!-- encoder 默认配置为PatternLayoutEncoder --> <encoder> <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n </pattern> </encoder> </appender> <logger name="dao" level="DEBUG"/> <!--自己的dao层--> <logger name="cm.mbs.dao" level="INFO"/> <root level="INFO"> <appender-ref ref="STDOUT"/> </root> </configuration>
5.创建mybatis-config.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> <!--使用logback的配置--> <settings> <setting name="logPrefix" value="dao." /> </settings> <!--<settings>--> <!--<!– 指定使用LOG4J输出日志 –>--> <!--<setting name="logImpl" value="LOG4J"/>--> <!--</settings>--> <typeAliases> <!-- 配置包的别名，通常在使用类时需要使用类的全限定名称，使用该配置后只要直接使用类名即可 --> <package name="cm.mbs.entity"/> </typeAliases> <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/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true" /> <property name="username" value="root" /> <property name="password" value="root" /> </dataSource> </environment> </environments> <mappers> <!-- 在src/main/resources目录下创建mapper目录 --> <mapper resource="mapper/UserMapper.xml" /> </mappers> </configuration>
6.创建数据库表
SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; -- ---------------------------- -- Table structure for tb_user -- ---------------------------- DROP TABLE IF EXISTS `tb_user`; CREATE TABLE `tb_user` ( `id` int(32) NOT NULL AUTO_INCREMENT, `user_name` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `password` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `name` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `age` int(10) DEFAULT NULL, `sex` int(2) DEFAULT NULL, `birthday` date DEFAULT NULL, `created` datetime(0) DEFAULT NULL, `updated` datetime(0) DEFAULT NULL, PRIMARY KEY (`id`) USING BTREE ) ENGINE = InnoDB AUTO_INCREMENT = 4 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic; -- ---------------------------- -- Records of tb_user -- ---------------------------- INSERT INTO `tb_user` VALUES (1, ‘zs‘, ‘123456‘, ‘张三‘, 22, 1, ‘1990-09-02‘, ‘2019-10-22 11:07:19‘, ‘2019-10-22 11:07:19‘); INSERT INTO `tb_user` VALUES (2, ‘ls‘, ‘123456‘, ‘李四‘, 23, 1, ‘1993-09-05‘, ‘2019-10-22 11:07:19‘, ‘2019-10-22 11:07:19‘); INSERT INTO `tb_user` VALUES (3, ‘ww‘, ‘123456‘, ‘王五‘, 24, 1, ‘1990-09-09‘, ‘2019-10-22 12:32:04‘, ‘2019-10-22 12:32:04‘); SET FOREIGN_KEY_CHECKS = 1;
7.创建实体类
@Data //这个是lombok的注解，为每一个私有属性创建get set方法 @NoArgsConstructor //lombok 无参构造器 public class User { private Long id; private String userName; private String password; }
8.创建dao
public interface UserMapper { List<User> selectAll(); }
9.创建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="cm.mbs.dao.UserMapper"> <select id="selectAll" resultType="User"> select Id,UserName,Password from t_user </select> </mapper>
10.编写测试类
public class UserMapperTest { private static SqlSessionFactory sqlSessionFactory; @BeforeClass public static void init() { InputStream is = null; try { String resource = "mybatis-config.xml"; is = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(is); } catch (Exception e) { e.printStackTrace(); } finally { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } } @Test public void testSelectAll() { try (SqlSession sqlSession = sqlSessionFactory.openSession()) { List<User> list = sqlSession.selectList("selectAll"); for (User user : list) { System.out.println(user.getUserName() + " " + user.getPassword()); } } } }
11.mybatis的启动理解
1. 构建sqlSessionFactory (UserMapperTest.java)
// 指定全局配置文件 String resource = "mybatis-config.xml"; // 读取配置文件 InputStream is = Resources.getResourceAsStream(resource); // 构建sqlSessionFactory SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
2. 打开sqlSession对话，并执行sql (UserMapperTest.java)
// 获取sqlSession SqlSession sqlSession = sqlSessionFactory.openSession()； // 操作CRUD，指定statement，规则：命名空间+“.”+statementId List<User> list = sqlSession.selectList("selectAll"); // 这个地方也可以使用 getMapper来获取mapper对象例如 UserMapper mapper = sqlSession.getMapper(UserMapper.class); // 执行查询方法 List<User> users = mapper.selectAll();
标签：exist char ble 数据库表 map thread doc star 理解
原文地址：https://www.cnblogs.com/L-o-g-i-c/p/11724844.html
