mybatis-配置檔案
阿新 • • 發佈：2021-11-11
目錄
標籤順序
configuration (properties?, settings?, typeAliases?, typeHandlers?, objectFactory?, objectWrapperFactory?, reflectorFactory?, plugins?, environments?, databaseIdProvider?, mappers?)
環境
/* Navicat Premium Data Transfer Source Server : school Source Server Type : MySQL Source Server Version : 80022 Source Host : localhost:3306 Source Schema : school Target Server Type : MySQL Target Server Version : 80022 File Encoding : 65001 Date: 10/11/2021 15:02:04 */ SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; -- ---------------------------- -- Table structure for grade -- ---------------------------- DROP TABLE IF EXISTS `grade`; CREATE TABLE `grade` ( `gradeId` int(0) NOT NULL AUTO_INCREMENT, `gradeName` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, PRIMARY KEY (`gradeId`) USING BTREE ) ENGINE = InnoDB AUTO_INCREMENT = 3 CHARACTER SET = utf8 COLLATE = utf8_bin ROW_FORMAT = Dynamic; -- ---------------------------- -- Records of grade -- ---------------------------- INSERT INTO `grade` VALUES (1, 'S1'); INSERT INTO `grade` VALUES (2, 'Y1'); SET FOREIGN_KEY_CHECKS = 1;
package com.fly.entity; /** * @author 26414 */ public class Grade { private Integer gradeId; private String gradeName; @Override public String toString() { return "Grade{" + "gradeId=" + gradeId + ", gradeName='" + gradeName + '\'' + '}'; } public Integer getGradeId() { return gradeId; } public void setGradeId(Integer gradeId) { this.gradeId = gradeId; } public String getGradeName() { return gradeName; } public void setGradeName(String gradeName) { this.gradeName = gradeName; } }
<?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/school?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8&allowPublicKeyRetrieval=true"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<!--這裡填sql對映檔案的位置-->
<mapper resource="mapper/GradeMapper.xml"/>
</mappers>
</configuration>
package com.fly.dao;
import com.fly.entity.Grade;
/**
* @author 26414
*/
public interface GradeMapper {
/**
* 根據id查詢年級
* @param gradeId 年級id
* @return gradeId對應的年級
*/
Grade getGradeById(Integer gradeId);
}
properties
在類路徑下建立dbconfig.properties檔案
db.driver=com.mysql.cj.jdbc.Driver
db.url=jdbc:mysql://localhost:3306/school?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8&allowPublicKeyRetrieval=true
db.username=root
db.password=123456
#這裡不能有空格
測試
@Test
public void test2() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
//通過反射得到代理物件
GradeMapper mapper = sqlSession.getMapper(GradeMapper.class);
Grade grade = mapper.getGradeById(1);
System.out.println("mapper = " + mapper);
System.out.println("grade = " + grade);
sqlSession.close();
}
由於mybatis和spring整合後，資料庫的配置都交給spring管理，這個標籤瞭解即可
settings
typeAliases
給單個Java 型別設定別名
<!-- mybatis-config.xml -->
<typeAliases>
<!--預設是類名首字母小寫，不區分大小寫-->
<typeAlias type="com.fly.entity.Grade"/>
</typeAliases>
測試
@Test
public void test2() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
//通過反射得到代理物件
GradeMapper mapper = sqlSession.getMapper(GradeMapper.class);
Grade grade = mapper.getGradeById(1);
System.out.println("mapper = " + mapper);
System.out.println("grade = " + grade);
sqlSession.close();
}
也可以使用alias屬性自定義別名
<!-- mybatis-config.xml -->
<typeAliases>
<typeAlias type="com.fly.entity.Grade" alias="gra"/>
</typeAliases>
執行test2方法測試
給整個包下的類設定別名
<!-- mybatis-config.xml -->
<typeAliases>
<!--不區分大小寫-->
<package name="com.fly.entity"/>
</typeAliases>
對映檔案不用改，執行test2
@Alias
假如entity包下面有Grade類，entity包的子包也有Grade類，給entity包起別名就會報錯，可以用@Alias單獨設定別名
已經有的別名
environments
transactionManager
dataSource
databaseIdProvider
mappers
class屬性
<mappers>
<!--這裡填sql對映檔案的位置-->
<!--
resource:引用類路徑下的對映檔案
url：引用網路路徑或者磁碟路徑的檔案
-->
<!-- <mapper resource="mapper/GradeMapper.xml"/>-->
<!--
介面和對映檔案必須在同一個包下面，並且名字相同
-->
<mapper class="com.fly.dao.GradeMapper"/>
</mappers>
執行test2方法測試
或者將sql語句寫在方法上面
package com.fly.dao;
import com.fly.entity.Grade;
import org.apache.ibatis.annotations.Select;
/**
* @author 26414
*/
public interface GradeMapper2 {
/**
* 根據id查詢年級
* @param gradeId 年級id
* @return gradeId對應的年級
*/
@Select("select * from grade where gradeId = #{gradeId}")
Grade getGradeById(Integer gradeId);
}
<mappers>
<!--mybatis-config.xml-->
<mapper class="com.fly.dao.GradeMapper2"/>
</mappers>
測試
@Test
public void test3() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
//通過反射得到代理物件
GradeMapper2 mapper = sqlSession.getMapper(GradeMapper2.class);
Grade grade = mapper.getGradeById(1);
System.out.println("mapper = " + mapper);
System.out.println("grade = " + grade);
sqlSession.close();
}