Spring Boot+Jpa多数据源配置的完整步骤

湛蓝之海

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关于
有时候，随着业务的发展，项目关联的数据来源会变得越来越复杂，使用的数据库会比较分散，这个时候就会采用多数据源的方式来获取数据。另外，多数据源也有其他好处，例如分布式数据库的读写分离，集成多种数据库等等。
下面分享我在实际项目中配置多数据源的案例。话不多说了，来一起看看详细的介绍吧
步骤
1.application.yml文件中，配置数据库源。这里primary是主库，secondary是从库。

server:
 port: 8089
 
# 多数据源配置
#primary
spring:
 primary:
 datasource:
  url: jdbc:mysql://127.0.0.1:3306/database1?autoreconnect=true&useunicode=true&characterencoding=utf-8&usessl=false&uselegacydatetimecode=false&servertimezone=asia/shanghai
  username: root
  password: ******
  driver-class-name: com.mysql.jdbc.driver
 
 #secondary
 secondary:
 datasource:
  url: jdbc:mysql://127.0.0.1:3306/database1?autoreconnect=true&useunicode=true&characterencoding=utf-8&usessl=false&uselegacydatetimecode=false&servertimezone=asia/shanghai
  username: root
  password: ******
  driver-class-name: com.mysql.jdbc.driver
 
 jpa:
 hibernate:
  primary-dialect: org.hibernate.dialect.mysql5dialect
  secondary-dialect: org.hibernate.dialect.mysql5dialect
 open-in-view: true
 show-sql: true

2.创建一个spring配置类，其中spring.primary.datasource的路径参考yml文件的配置。

@configuration
public class datasourceconfig {
 
 @bean(name = "primarydatasource")
 @qualifier("primarydatasource")
 @configurationproperties(prefix="spring.primary.datasource")
 public datasource primarydatasource() {
  return datasourcebuilder.create().build();
 }
 
 @bean(name = "secondarydatasource")
 @qualifier("secondarydatasource")
 @primary
 @configurationproperties(prefix="spring.secondary.datasource")
 public datasource secondarydatasource() {
  return datasourcebuilder.create().build();
 }
 
}

3.分别创建主库、从库的配置类。
注意：entity包和dao包的配置，以及@primary注解指定主库。
主库配置类：

@configuration
@enabletransactionmanagement
@enablejparepositories(
  entitymanagerfactoryref = "entitymanagerfactoryprimary",
  transactionmanagerref = "transactionmanagerprimary",
  basepackages = {"com.infinitus.yunxiao_data.dao.primary"}) //设置repository所在位置
public class primaryconfig {
 @autowired
 private jpaproperties jpaproperties;
 
 @autowired
 @qualifier("primarydatasource")
 private datasource primarydatasource;
 
 @primary
 @bean(name = "entitymanagerprimary")
 public entitymanager entitymanager(entitymanagerfactorybuilder builder) {
  return entitymanagerfactoryprimary(builder).getobject().createentitymanager();
 }
 
 @primary
 @bean(name = "entitymanagerfactoryprimary")
 public localcontainerentitymanagerfactorybean entitymanagerfactoryprimary(entitymanagerfactorybuilder builder) {
  return builder
  .datasource(primarydatasource)
  .properties(getvendorproperties(primarydatasource))
  .packages("com.infinitus.yunxiao_data.entity.primary") //设置实体类所在位置
  .persistenceunit("primarypersistenceunit")
  .build();
 }
 
 
 private map getvendorproperties(datasource datasource) {
  return jpaproperties.gethibernateproperties(datasource);
 }
 
 @primary
 @bean(name = "transactionmanagerprimary")
 public platformtransactionmanager transactionmanagerprimary(entitymanagerfactorybuilder builder) {
  return new jpatransactionmanager(entitymanagerfactoryprimary(builder).getobject());
 }
}

从库的配置类：

@configuration
@enabletransactionmanagement
@enablejparepositories(
  entitymanagerfactoryref = "entitymanagerfactorysecondary",
  transactionmanagerref = "transactionmanagersecondary",
  basepackages = {"com.infinitus.yunxiao_data.dao.secondary"}) //设置repository所在位置
public class secondaryconfig {
 @autowired
 private jpaproperties jpaproperties;
 
 @autowired
 @qualifier("secondarydatasource")
 private datasource secondarydatasource;
 
 @bean(name = "entitymanagersecondary")
 public entitymanager entitymanager(entitymanagerfactorybuilder builder) {
  return entitymanagerfactorysecondary(builder).getobject().createentitymanager();
 }
 
 @bean(name = "entitymanagerfactorysecondary")
 public localcontainerentitymanagerfactorybean entitymanagerfactorysecondary(entitymanagerfactorybuilder builder) {
  return builder
  .datasource(secondarydatasource)
  .properties(getvendorproperties(secondarydatasource))
  .packages("com.infinitus.yunxiao_data.entity.secondary") //设置实体类所在位置
  .persistenceunit("primarypersistenceunit")
  .build();
 }
 
 
 private map getvendorproperties(datasource datasource) {
  return jpaproperties.gethibernateproperties(datasource);
 }
 
 @bean(name = "transactionmanagersecondary")
 platformtransactionmanager transactionmanagersecondary(entitymanagerfactorybuilder builder) {
  return new jpatransactionmanager(entitymanagerfactorysecondary(builder).getobject());
 }
 
}

4.分别创建主、从库dao类。
主dao：

@repository
public interface primaryrepository extends jparepository<primaryentity, long> {
 
 @query(value = "select p from primaryentity p")
 list<primaryentity> querylist();
 
}

从dao：

@repository
public interface secondaryrepository extends jparepository<secondaryentity, long> {
 
 @query(value = "select p from secondaryentity p")
 list<secondaryentity> querylist();
 
}

5.分别创建主、从库entity类。
主entity：

@entity
@table(name = "holiday_scheme")
@entitylisteners(auditingentitylistener.class)
public class primaryentity extends abstractpersistable<long> {
 @column(name = "date")
 public string date;
 @column(name = "hour")
 public string hour;
 @column(name = "holiday")
 public string holiday;
 @column(name = "holiday_explain")
 public string holiday_explain;
 
 public string getdate() {
  return date;
 }
 
 public void setdate(string date) {
  this.date = date;
 }
 
 public string gethour() {
  return hour;
 }
 
 public void sethour(string hour) {
  this.hour = hour;
 }
 
 public string getholiday() {
  return holiday;
 }
 
 public void setholiday(string holiday) {
  this.holiday = holiday;
 }
 
 public string getholiday_explain() {
  return holiday_explain;
 }
 
 public void setholiday_explain(string holiday_explain) {
  this.holiday_explain = holiday_explain;
 }
 
 @override
 public string tostring() {
  return "primaryentity{" +
  "date='" + date + '\'' +
  ", hour='" + hour + '\'' +
  ", holiday='" + holiday + '\'' +
  ", holiday_explain='" + holiday_explain + '\'' +
  '}';
 }
}

从entity：

@entity
@table(name = "active_dashboards")
@entitylisteners(auditingentitylistener.class)
public class secondaryentity extends abstractpersistable<long> {
 
 @column(name = "dashboard_id")
 public string dashboard_id;
 @column(name = "user_id")
 public string user_id;
 @column(name = "order_index")
 public string order_index;
 
 public string getdashboard_id() {
  return dashboard_id;
 }
 
 public void setdashboard_id(string dashboard_id) {
  this.dashboard_id = dashboard_id;
 }
 
 public string getuser_id() {
  return user_id;
 }
 
 public void setuser_id(string user_id) {
  this.user_id = user_id;
 }
 
 public string getorder_index() {
  return order_index;
 }
 
 public void setorder_index(string order_index) {
  this.order_index = order_index;
 }
 
 @override
 public string tostring() {
  return "secondaryentity{" +
  "dashboard_id='" + dashboard_id + '\'' +
  ", user_id='" + user_id + '\'' +
  ", order_index='" + order_index + '\'' +
  '}';
 }
}

6.controller请求获取不同数据库的数据。

@restcontroller
@requestmapping("/database")
public class mailcontroller {
 private final logger logger = loggerfactory.getlogger(this.getclass());
 
 @autowired
 primaryrepository primaryrepository;
 @autowired
 secondaryrepository secondaryrepository;
 
 @requestmapping("/primary")
 @responsebody
 public string primary() {
  return primaryrepository.querylist().tostring();
 }
 
 @requestmapping("/secondary")
 @responsebody
 public string secondary() {
  return secondaryrepository.querylist().tostring();
 }
 
}

注意
下面提两个在配置多数据源时遇到的坑点，一不注意就掉坑了。
1.application类不需要配置@enablejparepositories注解，会报如下错误。

a component required a bean named 'entitymanagerfactory' that could not be f

2.注意检查dao类，获取数据的方法上格式是否正确，有没有某个字段是表中不存在的，避免启动异常。如下，secondaryentity表中是不存在job_name字段的，所以注释掉才能启动成功等。

//@query(value = "select p from secondaryentity p where p.job_name = ?1")
//list<secondaryentity> queryodcrecord(string job_name);

总结
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对CodeAE代码之家的支持。
原文链接：https://huangweicai.github.io/2019/01/08/SpringBoot+Jpa多数据源配置/