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idea新建Maven项目Mybatis-study 将项目里的src文件夹删掉 依次将此项目作为父项目
在Mybatis-study中新建模块mybatis-01
在mybatis的pom文件中可以看到其父项目为ybatis-study
<parent>
<artifactId>MyBatis-study</artifactId>
<groupId>org.example</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
在Mybatis-study的pom.xml中引入如下jar包
<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis --> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.5.9</version> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.29</version> </dependency> </dependencies>将IDEA和MySQL数据库建立连接：
根据实际情况填写user和password 填写之后点击Test Connection
测试成功之后点击Schemas选择你要链接的数据库
新建mybatis-config.xml配置文件 引入数据库资源
<?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> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.cj.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/smbms?useSSL=true&characterEncoding=UTF-8"/> <property name="username" value="root"/> <property name="password" value="root"/> </dataSource> </environment> </environments> <mappers> <mapper resource="com/kero/dao/UserMapper.xml" /> </mappers></configuration>创建实体类User 注意:实体类中成员变量名要和数据库表中字段名完全一致
package com.kero.pojo;public class User { private int id; private String name; private String password; public User() { } public User(int id, String name, String password) { this.id = id; this.name = name; this.password = password; } 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 getpassword() { return password; } public void setpassword(String pwd) { this.password = pwd; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", pwd='" + password + '\'' + '}'; }}编写工具类Utils
package com.kero.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;//sqlSessionFactorypublic class MyBatisUtils { private static SqlSessionFactory sqlSessionFactory; static { try { //使用Mybatis第一步 获取sqlSessionFactory对象 String resource = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } catch (IOException e) { throw new RuntimeException(e); } } public static SqlSession getSqlSession(){ return sqlSessionFactory.openSession(); }}定义接口
package com.kero.dao;import com.kero.pojo.User;import java.util.List;public interface UserMapper { //查询全部用户 List<User> getUserList(); //根据ID查询用户 User getUserByID(int id); //insert一个用户 int addUser(User user); //修改一个用户 int updateUser(User user); //删除一个用户 int deleteUser(int id);}定义Mapper文件 这里的Mapper文件相当于原来传统方式中接口的实现类
<?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"><!--namespace会绑定一个对应的Mapper接口--><mapper namespace="com.kero.dao.UserMapper"> <select id="getUserList" resultType="com.kero.pojo.User"> select * from smbms.user </select> <select id="getUserByID" parameterType="int" resultType="com.kero.pojo.User"> select * from smbms.user where id = #{id} </select> <insert id="addUser" parameterType="com.kero.pojo.User"> insert into smbms.user (id, name, password) VALUES (#{id},#{name},#{password}) </insert> <update id="updateUser" parameterType="com.kero.pojo.User"> update smbms.user set name=#{name},password=#{password} where id = #{id} </update> <delete id="deleteUser" parameterType="int"> delete from smbms.user where id = #{id} </delete></mapper>编写测试类
import com.kero.dao.UserMapper;import com.kero.pojo.User;import com.kero.utils.MyBatisUtils;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.List;public class test { @Test public void test(){ SqlSession session = MyBatisUtils.getSqlSession(); UserMapper mapper = session.getMapper(UserMapper.class); List<User> userList = mapper.getUserList(); for (User l:userList) { System.out.println(l.toString()); } session.close(); } @Test public void testgetUserByID(){ SqlSession session = MyBatisUtils.getSqlSession(); UserMapper mapper = session.getMapper(UserMapper.class); User userByID = mapper.getUserByID(1); System.out.println(userByID); session.close(); } //增删改需要提交事务 @Test public void testaddUser(){ SqlSession session = MyBatisUtils.getSqlSession(); UserMapper mapper = session.getMapper(UserMapper.class); int zhhgf = mapper.addUser(new User(10, "zhhgf", "1k23jbjk")); System.out.println(zhhgf); session.commit(); //提交事务 session.close(); } @Test public void testupdateUser(){ SqlSession session = MyBatisUtils.getSqlSession(); UserMapper mapper = session.getMapper(UserMapper.class); int i = mapper.updateUser(new User(8,"asdfsdf","234sdfs")); session.commit(); //提交事务 session.close(); } @Test public void testdeleteUser(){ SqlSession session = MyBatisUtils.getSqlSession(); UserMapper mapper = session.getMapper(UserMapper.class); int i = mapper.deleteUser(8); session.commit(); //提交事务 session.close(); }}测试查询功能 : 输出结果与数据库表中数据
User{id=1, name='Sugawara Ryota', pwd='8X8Jq7HVNs'}
User{id=2, name='Shawn Mills', pwd='R78IHGDSXr'}
User{id=3, name='Matsuda Hina', pwd='mUi3CVA7mc'}
User{id=4, name='Cynthia Hawkins', pwd='NO1EwWbOs9'}
User{id=5, name='Rachel Bennett', pwd='YefuPVxzb9'}
tips:
如果一切配置正常但出现java.lang.ExceptionInInitializerError
Caused by org.apache.ibatis.execeptions.PersistenceExecepyion错误
是因为:maven由于它的约定大于配置 我们写的配置文件可能会出现无法被导出或者生效的问题解决方案 在pom.xml文件中添加如下代码
<build> <resources> <resource> <directory>src/main/resources</directory> <includes> <include>***.xml</include> </includes> <filtering>true</filtering> </resource> <resource> <directory>src/main/java</directory> <includes> <include>***.xml</include> </includes> <filtering>true</filtering> </resource> </resources></build>关于“Mybatis怎么实现一个增删改查程序”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识，可以关注编程网行业资讯频道，小编每天都会为大家更新不同的知识点。
