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。
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@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
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