【Mybatis】mybatis-spring源码编译

　　本章介绍Mybatis与Spring整合的mybatis-spring.jar的编译，阅读本章前，现看

　　【Spring】Spring源码编译 和 【Mybatis】MyBatis源码编译

环境准备

• Maven：3.6.3
• Jdk：1.8.0_181
• idea

1、下载mybatis-spring源码

　　官网地址：https://github.com/mybatis/spring

　　选择需要的版本下载，本例下载的是 mybatis-spring-2.0.1，下载完后解压。打开pom.xml，查看mybatis的依赖的父工程版本

　　

2、下载载mybatis-parent源码

　　选择mybatis对应的mybatis-parent版本，本例版本是 mybatis-parent-31

　　官网地址：https://github.com/mybatis/parent

　　

3、源码导入Idea

　　在Idea中新建一个空项目，将 mybatis-spring 、 mybatis-parent 都放到空项目下，并导入模块

　　本例直接放在上一章（【Mybatis】MyBatis源码编译） mybatis 源码目录中

　　

4、编译mybatis-parent源码，编译mybatis源码

1、编译mybatis-parent项目

　　切换mybatis-parent项目： 

　　命令：mvn clean install

2、编译mybatis-spring项目

　　切换mybatis-spring项目（可以修改一下版本号，修改成自己特有的版本，方便区分）： 

　　修改mybatis-spring版本（2.0.1-MY）。避免与官网依赖相同版本

　　命令：mvn install -Dmaven.test.skip=true

5、测试使用源码

运行mybatis-spring项中的测试类

　　org.mybatis.spring.SqlSessionFactoryBeanTest.java#testDefaults()

　　

　　运行成功，说明已经编译好了

6、Demo使用源码

1、安装 mybatis源码 和 mybatis-spring 源码

　　将项目中 mybatis源码（使用自己的版本号: 3.5.1-MY） 和 mybatis-spring 源码（使用自己的版本号: 2.0.1-MY），

　　安装的maven仓库中，这样其他项目引用你编译的源码就能看到其中的注释

　　　　使用Maven插件：maven-source-plugin

<!-- 生成sources源码包的插件 -->
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-source-plugin</artifactId>
    <version>3.2.1</version>
    <configuration>
        <attach>true</attach>
    </configuration>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>jar-no-fork</goal>
            </goals>
        </execution>
    </executions>
</plugin>

　　使用命令：mvn install

　　

2、在Spring源码目录中新建测试项目

　　项目参考：【Spring】Spring源码编译

　　

　　1、spring-my-mybatis.gradle，gradle配置文件如下：引入自己编译的 mybatis源码 和 mybatis-spring 源码

description = "Spring MY MYBATIS"

apply plugin: "kotlin"

dependencies {
    compile "mysql:mysql-connector-java:8.0.12"
    compile "com.alibaba:druid:1.1.8"

    compile "org.mybatis:mybatis:3.5.1-MY"
    compile "org.mybatis:mybatis-spring:2.0.1-MY"


    compile "ognl:ognl:3.2.15"
    compile "org.javassist:javassist:3.27.0-GA"

    compile(project(":spring-core"))
    optional(project(":spring-aop"))
    optional(project(":spring-beans"))
    optional(project(":spring-context"))
    optional(project(":spring-jdbc"))
    optional(project(":spring-orm"))
    optional(project(":spring-tx"))
}

　　2、项目配置类 SpringMyBatisConfig.java

package com.test.spring.mybatis.config;

import com.alibaba.druid.pool.DruidDataSource;
import com.test.spring.mybatis.entity.Employee;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.TransactionManager;

import javax.sql.DataSource;
import java.io.IOException;

@Configuration
// 扫描Service，注入Spring
@ComponentScan("com.test.spring.mybatis.service")
// 扫描Mapper
@MapperScan("com.test.spring.mybatis.mapper")
public class SpringMyBatisConfig {

    // 数据源
    @Bean("dataSource")
    public DataSource dataSource(){
        System.out.println("初始化数据源 DruidDataSource ");

        String url="jdbc:mysql://127.0.0.1:3306/test_mybatis?allowPublicKeyRetrieval=true&useSSL=true";
        String username = "root";
        String password = "123456";
        String driverClassName = "com.mysql.cj.jdbc.Driver";

        DruidDataSource druidDataSource = new DruidDataSource();
        druidDataSource.setUsername(username);
        druidDataSource.setPassword(password);
        druidDataSource.setUrl(url);
        druidDataSource.setDriverClassName(driverClassName);

        return druidDataSource;
    }

    // 事物管理器
    @Bean
    public TransactionManager transactionManager(){
        return new DataSourceTransactionManager(dataSource());
    }

    // SqlSeesion工厂Bean
    @Bean
    public SqlSessionFactoryBean sqlSessionFactory() throws IOException {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource());
        // 设置 MyBatis 配置文件路径
        factoryBean.setConfigLocation(new ClassPathResource("mybatis/mybatis-config.xml"));
        // 设置 SQL 映射文件路径
        factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/*.xml"));
        // 这是类型别名
        factoryBean.setTypeAliases(new Class[]{Employee.class});
        return factoryBean;
    }
}

　　3、实体类 Employee.java

package com.test.spring.mybatis.entity;

import java.io.Serializable;

public class Employee implements Serializable {

    private Integer id;
    private String lastName;
    private String gender;
    private String email;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    @Override
    public String toString() {
        return "Employee [id=" + id + ", lastName=" + lastName + ", gender=" + gender + ", email=" + email + "]";
    }


}

　　4、Mapper类 EmployeeMapper.java

package com.test.spring.mybatis.mapper;

import com.test.spring.mybatis.entity.Employee;
import org.apache.ibatis.annotations.Param;

public interface EmployeeMapper {
    
    public Employee getEmployeeById(@Param("id") Integer id);

}

　　5、服务类 EmployeeService.java

package com.test.spring.mybatis.service;

import com.test.spring.mybatis.entity.Employee;
import com.test.spring.mybatis.mapper.EmployeeMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class EmployeeService {

    @Autowired
    EmployeeMapper employeeMapper;

    public Employee getEmployeeById(Integer id) {
        return employeeMapper.getEmployeeById(id);
    }
}

　　6、mybatis全局配置文件 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>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
</configuration>

　　

　　7、Mapper配置文件 EmployeeMapper　

<?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.test.spring.mybatis.mapper.EmployeeMapper">

    <select id="getEmployeeById"
            resultType="com.test.spring.mybatis.entity.Employee">
        select id, last_name lastName, gender, email from employee
        <where>
            <if test="1 > 0">
                AND id = #{id}
            </if>
        </where>
    </select>
</mapper>

　　8、主启动类 SpringMyBatisMainTest.java

package com.test.spring.mybatis;

import com.test.spring.mybatis.config.SpringMyBatisConfig;
import com.test.spring.mybatis.entity.Employee;
import com.test.spring.mybatis.service.EmployeeService;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class SpringMyBatisMainTest {

    public static void main(String[] args) {
        AnnotationConfigApplicationContext context =
                new AnnotationConfigApplicationContext(SpringMyBatisConfig.class);

        EmployeeService employeeService = context.getBean(EmployeeService.class);

        Employee employee = employeeService.getEmployeeById(1);

        System.out.println(employee);

    }
}

3、测试运行主启动类

　　

　　运行成功，这样即可在项目中看到自己编译的带注释的 mybatis源码 和 mybatis-spring 源码

可能出现的问题

　　问题一：Javassist 依赖问题

警告: Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in com.test.spring.mybatis.config.SpringMyBatisConfig: Invocation of init method failed; nested exception is java.lang.IllegalStateException: Cannot enable lazy loading because Javassist is not available. Add Javassist to your classpath.
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in com.test.spring.mybatis.config.SpringMyBatisConfig: Invocation of init method failed; nested exception is java.lang.IllegalStateException: Cannot enable lazy loading because Javassist is not available. Add Javassist to your classpath.　　

　　解决：添加依赖javassist，同时将ognl依赖也添加好，即可解决

    compile "ognl:ognl:3.2.15"
    compile "org.javassist:javassist:3.27.0-GA"