Mybatis配置並實現（XML方式）
阿新 • • 發佈：2020-09-15
Mybatis配置並實現（XML方式）
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idea中建立一個maven專案
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在pom檔案中匯入下面的依賴
<!--mybatis核心包--> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.6</version> </dependency> <!--mysql資料庫驅動包--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.18</version> </dependency> <!--log4j日誌包--> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> -
建立一個java原始檔夾和resources資原始檔夾並準備好mybatis配置檔案mybaits.xml和資料庫檔案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> <!--資料庫引數檔案--> <properties resource="db.properties"></properties> <!--別名的配置，可以不用--> <typeAliases> <package name="cn.cqy.domain"></package> </typeAliases> <!--配置環境，可以多個，這裡要設定一個預設使用的環境--> <environments default="dev"> <!--配置環境名，唯一一個id名稱--> <environment id="dev"> <!--事務管理 type:JDBC(支援事務)/MANAGED(什麼都不做)--> <transactionManager type="JDBC"></transactionManager> <!--資料來源, 連線池 type(POOLED):MyBatis自帶的連線池--> <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> <!--這個mappers代表的是相應的ORM對映檔案 這裡先準備好了--> <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
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資料庫準備，略。
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準備相應的物件
建立一個Student物件，和資料庫的表對應
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的準備 ，建立一個mapper資料夾，並在內建立一個StudentMapper介面
public interface StudentMapper { //查詢學生表全部資訊 public List<Student> selectAll(); //根據姓名查詢學生 public Student selectByName(String name); //插入一條學生資訊 public void insertOne(Student stu); //根據姓名刪除一條學生資訊 public void deleteByName(String name); //根據姓名修改一條學生資訊 public void updateByName(Student stu); } -
在resoures資原始檔夾下建立和mapper資料夾路徑相同的資料夾
然後建立對映檔案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"> <!--名稱空間 必須和所對應介面的全限定名一致--> <mapper namespace="cn.cqy.mapper.StudentMapper"> <!--定義sql的標籤的id，需要和對應介面的方法名一致 resultType的型別在沒有配置別名的情況下，應該是POJO類的全限定名 如cn.cqy.domain.Student--> <select id="selectAll" resultType="Student"> SELECT s_id,s_name,s_birth,s_sex FROM student </select> <!--引數型別為自定型別沒有別名，輸入型別全限定名，為Java型別時輸入其對應對映名 如 long:大Long _long:小long (具體的對應請參見文件)--> <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> -
抽取出一個MybatisUtil工具類
public class MybatisUtil { private static SqlSessionFactory sqlSessionFactory; //靜態程式碼塊：在使用的時候先執行，並且執行一次 static { try { InputStream is = Resources.getResourceAsStream("mybatis.xml"); SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); //建立一個工廠例項（載入了我們的配置檔案） sqlSessionFactory = builder.build(is); } catch (IOException e) { e.printStackTrace(); } } /** *拿到了一個SqlSession物件 */ public static SqlSession getSqlSession() { return sqlSessionFactory.openSession(); } public static void closeSqlSession(SqlSession sqlSession) { if (sqlSession != null) { sqlSession.close(); } } } -
編寫測試類
public class SqlTest { @Test public void testSelectAll() { //通過工具類獲得SqlSession物件 SqlSession sqlSession = MybatisUtil.getSqlSession(); //獲取到繫結到SqlSession的POJO類對應的對映 StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class); //通過對映呼叫查詢方法 List<Student> students = studentMapper.selectAll(); //關閉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("吳蘭"); 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、刪、改需要提交事務，否則不會修改 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(); } } -
測試查詢結果