JAVA MyBatis Introduction Learning Process Record
- 2021-10-13 07:16:30
- OfStack
Directory 1. Mybatis1, mybatis-config. xml2, Mapper. xml3, db. properties4, MybatisUtils tool class 5, multi-pair 1AND multi-pair 1: 6, use annotation development 7, custom cache: ehcache8, mybatis other tools 2. MAVEN resource export error resolution 3. Common dependency import 4. LOG4J1, log4j. properties configuration file 2, log4j configuration in mybatis-config. xml 3, easy-to-use plug-ins: 1, lombok summary
1. Mybatis
1. 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>
<!-- External introduction db-->
<properties resource="db.properties"/>
<settings>
<!-- Configure Log File -->
<!-- <setting name="logImpl" value="STDOUT_LOGGING"/>-->
<setting name="logImpl" value="log4j"/>
<!-- Open A_NAME==>aName-->
<setting name="mapUnderscoreToCamelCase" valie="true"
</settings>
<!-- Reduced type -->
<typeAliases> <typeAlias type="com.wang.pojo.User" alias="User"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/wang/dao/UserMapper.xml"/>
</mappers>
</configuration>
2. Mapper. 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="com.wang.dao.UserDao">
<select id="getUserList" resultType="User">
select * from mybatis.user
</select>
</mapper>
3. db. properties
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis
username=root
password=123456
4. MybatisUtils tool class
package com.wang.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;
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
InputStream inputStream = null;
try {
String resource = "mybatis-config.xml";
inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getsqlsession() {
return sqlSessionFactory.openSession();
}
}
5. Many-to-1AND Many-to-1:
Configured in Mapper. xml
association Object Many-to-One
collection Set 1-to-many
From interpreting with parameters:
javaType java Type ofType Generic Constraint Types
6. Use annotations to develop
You can use annotations in the interface for development, omitting Mapper. xml
@Select("select * from mybatis.User")
List<User> getUserList();
In mybatis-config.xml Configuration in
<mappers>
<mapper class="com.wang.Dao.UserMapper"
</mappers>
7. Custom cache: ehcache
8. Other tools of mybatis
mybatis Hepler: https://pagehelper.github.io/
2. MAVEN resource export error resolution
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
3. Commonly used dependency imports
<!-- Import dependencies -->
<dependencies>
<!-- mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.49</version>
</dependency>
<!-- mybatis-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<!-- junit-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
</dependency>
<!-- lombok-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.20</version>
</dependency>
<!-- servlet and jsp-->
<dependency>
<groupId>org.mortbay.jetty</groupId>
<artifactId>servlet-api-2.5</artifactId>
<version>6.1.7</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
</dependency>
<!-- standard-->
<dependency>
<groupId>org.apache.karaf.assemblies.features</groupId>
<artifactId>standard</artifactId>
<version>2.4.4</version>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<!-- jstl-->
<dependency>
<groupId>javax.servlet.jsp.jstl</groupId>
<artifactId>jstl-api</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.glassfish.web</groupId>
<artifactId>jstl-impl</artifactId>
<version>1.2</version>
</dependency>
<!-- fastjson-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.76</version>
</dependency>
<!--Log4j-->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
4. LOG4J
1. log4j. properties configuration file
<!-- Import dependencies -->
<dependencies>
<!-- mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.49</version>
</dependency>
<!-- mybatis-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<!-- junit-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
</dependency>
<!-- lombok-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.20</version>
</dependency>
<!-- servlet and jsp-->
<dependency>
<groupId>org.mortbay.jetty</groupId>
<artifactId>servlet-api-2.5</artifactId>
<version>6.1.7</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
</dependency>
<!-- standard-->
<dependency>
<groupId>org.apache.karaf.assemblies.features</groupId>
<artifactId>standard</artifactId>
<version>2.4.4</version>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<!-- jstl-->
<dependency>
<groupId>javax.servlet.jsp.jstl</groupId>
<artifactId>jstl-api</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.glassfish.web</groupId>
<artifactId>jstl-impl</artifactId>
<version>1.2</version>
</dependency>
<!-- fastjson-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.76</version>
</dependency>
<!--Log4j-->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
2. Configuration of log4j in mybatis-config. xml
<settings>
<setting name="logImpl" value="LOG4J"/>
</settings>
3. Use scenarios
Introducing into a concrete class
<?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="com.wang.dao.UserDao">
<select id="getUserList" resultType="User">
select * from mybatis.user
</select>
</mapper>
0
Easy plug-ins:
1. lombok
Commonly used notes:
@ Data Auto Generate geter seter @ AllArgsConstructor Generates Parameterized Constructors @ NoArgsConstructor Generates Parameterless Constructors= "logImpl" value= "LOG4J"/ >
<?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="com.wang.dao.UserDao">
<select id="getUserList" resultType="User">
select * from mybatis.user
</select>
</mapper>
1
Commonly used notes:
@ Data Auto Generate geter seter @ AllArgsConstructor Generates Parameterized Constructors @ NoArgsConstructor Generates Parameterless Constructors
Summarize
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