文章目錄

• • 目錄結構
  • 添加MyBatis的坐標及其他依賴
  • 準備數據庫環境
  • 編寫User實體類（提前安裝lombok插件并導入依賴）
  • 編寫核心文件SqlMapConfig.xml
  • 編寫映射文件UserMapper.xml
  • 運行截圖
  • CRUD操作

目錄結構

添加MyBatis的坐標及其他依賴

<dependencies><!-- https://mvnrepository.com/artifact/org.mybatis/mybatis --><!-- mybatis坐標 --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.5</version></dependency><!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --><!-- mysql驅動坐標 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.21</version></dependency><!-- https://mvnrepository.com/artifact/junit/junit --><!-- 單元測試坐標 --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.13.1</version><scope>test</scope></dependency><!-- https://mvnrepository.com/artifact/org.projectlombok/lombok --><!-- lombok坐標 --><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.14</version><scope>provided</scope></dependency><!-- https://mvnrepository.com/artifact/log4j/log4j --><!-- 日志坐標 --><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.17</version></dependency></dependencies>

準備數據庫環境

create database mybatis; use mybatis;CREATE TABLE `user` ( `id` int(11) NOT NULL AUTO_INCREMENT, `username` varchar(32) NOT NULL COMMENT '用戶名稱', `sex` char(1) DEFAULT NULL COMMENT '性別', `address` varchar(256) DEFAULT NULL COMMENT '地址', PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; insert into `user` (`id`, `username`, `sex`, `address`) values(NULL,'我愛羅','男','砂隱村'); insert into `user` (`id`, `username`, `sex`, `address`) values(NULL,'由木人','女','云隱村'); insert into `user` (`id`, `username`, `sex`, `address`) values(NULL,'矢倉','男','霧隱村'); insert into `user` (`id`, `username`, `sex`, `address`) values(NULL,'老紫','男','巖隱村');

編寫User實體類（提前安裝lombok插件并導入依賴）

import lombok.Data;@Data public class User {private Integer id; //定義類型為Integer，在初始化的時候會設置為null；而設置類型為int的話，數據初始化為0，可能會具有實際意義，產生二義性private String username;private String sex;private String address; }

編寫核心文件SqlMapConfig.xml

在官網中就可以看到核心文件，復制過來即可使用

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration><!--配置數據庫運?環境--><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://127.0.0.1:3306/mybatis?characterEncoding=utf8&amp;useSSL=false&amp;serverTimezone=UTC&amp;rewriteBatchedStatements=true"/><property name="username" value="root"/><property name="password" value="root"/></dataSource></environment></environments><!--配置關聯的SQL語句的映射?件--><mappers><mapper resource="UserMapper.xml"/></mappers> </configuration>

編寫映射文件UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="userMapper"><!--查詢所有?戶--><select id="findAll" resultType="com.byc.pojo.User">select * from user</select> </mapper>

編寫測試類

import com.byc.pojo.User; 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 org.junit.Test;import java.io.IOException; import java.io.InputStream; import java.util.List;public class UserTest {@Testpublic void findAll() throws IOException {//加載核?配置?件 SqlMapConfig.xmlInputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");//構造SQLSessionFactory對象SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//構造SQLSession對象SqlSession sqlSession = sqlSessionFactory.openSession();//執?查詢語句List<User> userList = sqlSession.selectList("userMapper.findAll");for (User user : userList) {System.out.println("user = " + user);}//釋放資源sqlSession.close();} }

運行截圖

CRUD操作

插入

<insert id="insert" parameterType="com.byc.pojo.User">insert into user values (#{id},#{username},#{sex},#{address})</insert> import com.byc.pojo.User; 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 org.junit.Test;import java.io.IOException; import java.io.InputStream;public class UserTest {@Testpublic void insert() throws IOException {//加載核?配置?件 SqlMapConfig.xmlInputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");//構造SQLSessionFactory對象SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//構造SQLSession對象SqlSession sqlSession = sqlSessionFactory.openSession();//執行插入語句User user = new User();user.setUsername("鳴人");user.setSex("男");user.setAddress("木葉村");int line = sqlSession.insert("userMapper.insert", user);System.out.println("line = "+line);sqlSession.commit();//釋放資源sqlSession.close();} }

和上面不一樣的是mybatis提交數據的時候默認設置的是手動提交，所以在資源釋放之前需要增添資源提交的代碼sqlSession.commit();

由于在數據庫表結構中，設置用戶id是主鍵自增型，所以需要獲取并在程序中使用
2. 刪除

<delete id="delete" parameterType="java.lang.Integer">delete from user where id=#{id}</delete> import com.byc.pojo.User; 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 org.junit.Test;import java.io.IOException; import java.io.InputStream; import java.util.List;public class UserTest {@Testpublic void delete() throws IOException {//加載核心配置?件 SqlMapConfig.xmlInputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");//構造SQLSessionFactory對象SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//構造SQLSession對象SqlSession sqlSession = sqlSessionFactory.openSession();sqlSession.delete("userMapper.delete",2);sqlSession.commit();//釋放資源sqlSession.close();} }

3. 更新

<update id="update" parameterType="com.byc.pojo.User">update user set username=#{username},sex=#{sex},address=#{address} where id=#{id}</update> import com.byc.pojo.User; 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 org.junit.Test;import java.io.IOException; import java.io.InputStream; import java.util.List;public class UserTest {@Testpublic void update() throws IOException {//加載核?配置?件 SqlMapConfig.xmlInputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");//構造SQLSessionFactory對象SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//構造SQLSession對象SqlSession sqlSession = sqlSessionFactory.openSession();//執?更新語句User user = new User();user.setId(7);user.setUsername("jack");user.setSex("男");user.setAddress("?本");sqlSession.update("userMapper.update",user);sqlSession.commit();//釋放資源sqlSession.close();} }

查詢
1）通過用戶ID

<select id="findById" parameterType="integer" resultType="com.byc.pojo.User">select * from user where id=#{id}</select> import com.byc.pojo.User; 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 org.junit.Test;import java.io.IOException; import java.io.InputStream; import java.util.List;public class UserTest {@Testpublic void findById() throws IOException {//加載核?配置?件 SqlMapConfig.xmlInputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");//構造SQLSessionFactory對象SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//構造SQLSession對象SqlSession sqlSession = sqlSessionFactory.openSession(); /* //執?查詢語句List<User> userList = sqlSession.selectList("userMapper.findAll");for (User user : userList) {System.out.println("user = " + user);}*/ // //執行插入語句 // User user = new User(); // user.setUsername("鳴人"); // user.setSex("男"); // user.setAddress("木葉村"); // int line = sqlSession.insert("userMapper.insert", user); // System.out.println("line = "+line); // sqlSession.commit(); // System.out.println("id = "+user.getId()); // sqlSession.delete("userMapper.delete",2); // sqlSession.commit(); // //執?更新語句 User user = new User(); user.setId(7); user.setUsername("jack"); user.setSex("男"); user.setAddress("?本"); sqlSession.update("userMapper.update",user); sqlSession.commit();//執?查詢語句User user = sqlSession.selectOne("userMapper.findById", 8);System.out.println("user = " + user);//釋放資源sqlSession.close();} }

創作挑戰賽新人創作獎勵來咯，堅持創作打卡瓜分現金大獎

總結

以上是生活随笔為你收集整理的Mybatis开发CRUD的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。