从零开始学springboot-jpa-atomikos多数据源

前言

前章我们已经能够流畅的写出一个基于springboot2.1.3的多数据源的案例了，而且我们选择很多，可以通过jpa搭建，也可以通过jdbc。有了多数据源，必然会碰到多数据源事务处理的问题，也就是分布式事务，所以，这节，我们就通过jpa多数据源+atomikos的方式来实现分布式事务的处理案例。

Atomikos介绍

Atomikos 是一个为Java平台提供增值服务的并且开源类事务管理器。我们通过它来管理事务。springboot本身对其有很好的支持，依赖为spring-boot-starter-jta-atomikos。

创建空项目

1.png

添加依赖

 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jta-atomikos</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

2.png

添加配置

application.yml：

spring:
  datasource:
    master:
      username: root
      password: 123456
      url: jdbc:mysql://192.168.145.131:3306/test
      driver-class-name: com.mysql.cj.jdbc.Driver
    slave:
      username: root
      password: 123456
      url: jdbc:mysql://192.168.145.131:3306/test2
      driver-class-name: com.mysql.cj.jdbc.Driver
  jta:
    atomikos:
      datasource:
        max-pool-size: 20
        borrow-connection-timeout: 60
      connectionfactory:
        max-pool-size: 20
        borrow-connection-timeout: 60
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true

hibernate.properties(和application.yml同目录):

##坑，springboot2.1.3已经不支持网上的那些控制jpa建innodb表的配置了，必须创建这个文件配置。
hibernate.dialect.storage_engine=innodb

建库

创建test、test2库即可，本次我们通过jpa自动建表，运行代码时会动创建student和teacher表
也可手动创建
test：

CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `age` int(11) NOT NULL,
  `grade` int(11) NOT NULL,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

test2:

CREATE TABLE `teacher` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `age` int(11) NOT NULL,
  `course` int(11) NOT NULL,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

完善

目录结构

3.png

根据目录结构，请自行创建package和class。

config/AtomikosJtaPlatform

package com.mrcoder.sbjpamultidbatomikos.config;

import org.hibernate.engine.transaction.jta.platform.internal.AbstractJtaPlatform;

import javax.transaction.TransactionManager;
import javax.transaction.UserTransaction;

public class AtomikosJtaPlatform extends AbstractJtaPlatform {

    private static final long serialVersionUID = 1L;

    static TransactionManager transactionManager;
    static UserTransaction transaction;

    @Override
    protected TransactionManager locateTransactionManager() {
        return transactionManager;
    }

    @Override
    protected UserTransaction locateUserTransaction() {
        return transaction;
    }
}

config/DataSourceConfig

package com.mrcoder.sbjpamultidbatomikos.config;

import com.atomikos.icatch.jta.UserTransactionImp;
import com.atomikos.icatch.jta.UserTransactionManager;
import org.hibernate.dialect.MySQL5Dialect;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.jta.JtaTransactionManager;
import javax.transaction.TransactionManager;
import javax.transaction.UserTransaction;

@Configuration
@ComponentScan
@EnableTransactionManagement
public class DataSourceConfig {

    @Bean
    public PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }


    //设置JPA特性
    @Bean
    public JpaVendorAdapter jpaVendorAdapter() {
        HibernateJpaVendorAdapter hibernateJpaVendorAdapter = new HibernateJpaVendorAdapter();
        //显示sql
        hibernateJpaVendorAdapter.setShowSql(true);
        //自动生成/更新表
        hibernateJpaVendorAdapter.setGenerateDdl(true);
        //设置数据库类型
        hibernateJpaVendorAdapter.setDatabase(Database.MYSQL);
        return hibernateJpaVendorAdapter;
    }

    @Bean(name = "userTransaction")
    public UserTransaction userTransaction() throws Throwable {
        UserTransactionImp userTransactionImp = new UserTransactionImp();
        userTransactionImp.setTransactionTimeout(10000);
        return userTransactionImp;
    }

    @Bean(name = "atomikosTransactionManager", initMethod = "init", destroyMethod = "close")
    public TransactionManager atomikosTransactionManager() throws Throwable {
        UserTransactionManager userTransactionManager = new UserTransactionManager();
        userTransactionManager.setForceShutdown(false);
        AtomikosJtaPlatform.transactionManager = userTransactionManager;
        return userTransactionManager;
    }

    @Bean(name = "transactionManager")
    @DependsOn({"userTransaction", "atomikosTransactionManager"})
    public PlatformTransactionManager transactionManager() throws Throwable {
        UserTransaction userTransaction = userTransaction();
        AtomikosJtaPlatform.transaction = userTransaction;
        TransactionManager atomikosTransactionManager = atomikosTransactionManager();
        return new JtaTransactionManager(userTransaction, atomikosTransactionManager);
    }

}

config/MasterConfig

package com.mrcoder.sbjpamultidbatomikos.config;

import com.mysql.cj.jdbc.MysqlXADataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jta.atomikos.AtomikosDataSourceBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;

import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.HashMap;

@Configuration
@DependsOn("transactionManager")
@EnableJpaRepositories(basePackages = "com.mrcoder.sbjpamultidbatomikos.entity.master", entityManagerFactoryRef = "masterEntityManager", transactionManagerRef = "transactionManager")
public class MasterConfig {
    @Autowired
    private JpaVendorAdapter jpaVendorAdapter;

    //master库
    @Primary
    @Bean(name = "masterDataSourceProperties")
    @Qualifier("masterDataSourceProperties")
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSourceProperties masterDataSourceProperties() {
        return new DataSourceProperties();
    }


    @Primary
    @Bean(name = "masterDataSource", initMethod = "init", destroyMethod = "close")
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource masterDataSource() throws SQLException {
        MysqlXADataSource mysqlXaDataSource = new MysqlXADataSource();
        mysqlXaDataSource.setUrl(masterDataSourceProperties().getUrl());
        mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
        mysqlXaDataSource.setPassword(masterDataSourceProperties().getPassword());
        mysqlXaDataSource.setUser(masterDataSourceProperties().getUsername());
        AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
        xaDataSource.setXaDataSource(mysqlXaDataSource);
        xaDataSource.setUniqueResourceName("xads1");
        xaDataSource.setBorrowConnectionTimeout(60);
        xaDataSource.setMaxPoolSize(20);
        return xaDataSource;

    }

    @Primary
    @Bean(name = "masterEntityManager")
    @DependsOn("transactionManager")
    public LocalContainerEntityManagerFactoryBean masterEntityManager() throws Throwable {

        HashMap<String, Object> properties = new HashMap<String, Object>();
        properties.put("hibernate.transaction.jta.platform", AtomikosJtaPlatform.class.getName());
        properties.put("javax.persistence.transactionType", "JTA");
        LocalContainerEntityManagerFactoryBean entityManager = new LocalContainerEntityManagerFactoryBean();
        entityManager.setJtaDataSource(masterDataSource());
        entityManager.setJpaVendorAdapter(jpaVendorAdapter);
        entityManager.setPackagesToScan("com.mrcoder.sbjpamultidbatomikos.entity.master");
        entityManager.setPersistenceUnitName("masterPersistenceUnit");
        entityManager.setJpaPropertyMap(properties);
        return entityManager;
    }
}

config/SlaveConfig

package com.mrcoder.sbjpamultidbatomikos.config;

import com.mysql.cj.jdbc.MysqlXADataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jta.atomikos.AtomikosDataSourceBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;

import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.HashMap;

@Configuration
@DependsOn("transactionManager")
@EnableJpaRepositories(basePackages = "com.mrcoder.sbjpamultidbatomikos.entity.slave", entityManagerFactoryRef = "slaveEntityManager", transactionManagerRef = "transactionManager")
public class SlaveConfig {
    @Autowired
    private JpaVendorAdapter jpaVendorAdapter;

    @Bean(name = "slaveDataSourceProperties")
    @Qualifier("slaveDataSourceProperties")
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSourceProperties slaveDataSourceProperties() {
        return new DataSourceProperties();
    }


    @Bean(name = "slaveDataSource", initMethod = "init", destroyMethod = "close")
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSource slaveDataSource() throws SQLException {
        MysqlXADataSource mysqlXaDataSource = new MysqlXADataSource();
        mysqlXaDataSource.setUrl(slaveDataSourceProperties().getUrl());
        mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
        mysqlXaDataSource.setPassword(slaveDataSourceProperties().getPassword());
        mysqlXaDataSource.setUser(slaveDataSourceProperties().getUsername());
        AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
        xaDataSource.setXaDataSource(mysqlXaDataSource);
        xaDataSource.setUniqueResourceName("xads2");
        xaDataSource.setBorrowConnectionTimeout(60);
        xaDataSource.setMaxPoolSize(20);
        return xaDataSource;
    }

    @Bean(name = "slaveEntityManager")
    @DependsOn("transactionManager")
    public LocalContainerEntityManagerFactoryBean slaveEntityManager() throws Throwable {
        HashMap<String, Object> properties = new HashMap<String, Object>();
        properties.put("hibernate.transaction.jta.platform", AtomikosJtaPlatform.class.getName());
        properties.put("javax.persistence.transactionType", "JTA");
        LocalContainerEntityManagerFactoryBean entityManager = new LocalContainerEntityManagerFactoryBean();
        entityManager.setJtaDataSource(slaveDataSource());
        entityManager.setJpaVendorAdapter(jpaVendorAdapter);
        entityManager.setPackagesToScan("com.mrcoder.sbjpamultidbatomikos.entity.slave");
        entityManager.setPersistenceUnitName("slavePersistenceUnit");
        entityManager.setJpaPropertyMap(properties);
        return entityManager;
    }
}

entity/master/Student

package com.mrcoder.sbjpamultidbatomikos.entity.master;

import javax.persistence.*;

@Entity(name = "student")
public class Student {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private int id;

    private String name;

    private int age;

    private int grade;

    public Student() {
    }

    public Student(String name, int age, int grade) {
        this.name = name;
        this.age = age;
        this.grade = grade;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", grade=" + grade +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public int getGrade() {
        return grade;
    }

    public void setGrade(int grade) {
        this.grade = grade;
    }
}

entity/master/StudentDao

package com.mrcoder.sbjpamultidbatomikos.entity.master;
import org.springframework.data.jpa.repository.JpaRepository;

public interface StudentDao extends JpaRepository<Student, Integer> {


}

entity/slave/Teacher

package com.mrcoder.sbjpamultidbatomikos.entity.slave;

import javax.persistence.*;

@Entity(name = "teacher")
public class Teacher {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private int id;
    private String name;
    private int age;
    private int course;

    public Teacher() {
    }

    public Teacher(String name, int age, int course) {
        this.name = name;
        this.age = age;
        this.course = course;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", course='" + course + '\'' +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public int getCourse() {
        return course;
    }

    public void setCourse(int course) {
        this.course = course;
    }
}

entity/slave/TeacherDao

package com.mrcoder.sbjpamultidbatomikos.entity.slave;
import org.springframework.data.jpa.repository.JpaRepository;

public interface TeacherDao extends JpaRepository<Teacher,Integer> {

}

service/CurdService

package com.mrcoder.sbjpamultidbatomikos.service;

import com.mrcoder.sbjpamultidbatomikos.entity.master.Student;
import com.mrcoder.sbjpamultidbatomikos.entity.master.StudentDao;
import com.mrcoder.sbjpamultidbatomikos.entity.slave.Teacher;
import com.mrcoder.sbjpamultidbatomikos.entity.slave.TeacherDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class CurdService {

    @Autowired
    private StudentDao studentDao;

    @Autowired
    private TeacherDao teacherDao;

    @Transactional
    public void add(int code) {
        Student s1 = new Student();
        s1.setAge(10);
        s1.setGrade(10);
        s1.setName("s1");
        studentDao.save(s1);

        Teacher t1 = new Teacher();
        t1.setAge(10);
        t1.setName("t1");
        t1.setCourse(10);
        teacherDao.save(t1);

        int result = 1/code;
    }
}

controller/JpaAtomikosController

package com.mrcoder.sbjpamultidbatomikos.controller;


import com.mrcoder.sbjpamultidbatomikos.entity.master.StudentDao;
import com.mrcoder.sbjpamultidbatomikos.service.CurdService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class JpaAtomikosController {

    @Autowired
    private CurdService curdService;

    @Autowired
    private StudentDao studentDao;

    @RequestMapping("/add")
    public void add() {
        curdService.add(1);
    }

    @RequestMapping("/test")
    public void test() {
        curdService.add(0);
    }

    @RequestMapping("/list")
    public void list() {
        System.out.println(studentDao.findAll());

    }
}

运行

http://localhost:8080/add 会在test库的student和test2库的teacher表中各新增一条记录

http://localhost:8080/test 人为的制造1/0的异常，异常触发事务，会发现两张表都不会新增记录。

项目地址

https://github.com/MrCoderStack/SpringBootDemo/tree/master/sb-jpa-multidb-atomikos

https://gitee.com/MrCoderStack/SpringBootDemo/tree/master/sb-jpa-multidb-atomikos

注意点

请一定注意，两张表为innodb引擎，若出现分布式事务无法触发，请优先查看表引擎。

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