SpringBoot集成Mybatis動態多數據源後，MybatisPlus的IPage失效的問題解決方案

時間 2020-01-08

標籤 springboot 集成 mybatis 動態數據 mybatisplus ipage 失效問題解決方案欄目 Spring 简体版

原文原文鏈接

背景

以前作數據抽取的時候，搭了一個mybatis動態數據源切換的架子。方便他們寫抽取的代碼。今天同事問我，架子裏面的mybatisplus的IPage失效了是什麼問題。想了一下，應該是寫動態數據源的時候，我自定義的mybatis的配置覆蓋了已有的配置。因而我讓他先把我寫的配置進行刪除，看是否正常。獲得回覆，刪除後正常。那麼到此問題緣由找到，接下來的解決方法，只要在配置中增長分頁器便可。mysql

解決方案

創建一個分頁器的bean配置

@Bean
public PaginationInterceptor paginationInterceptor() {
    return new PaginationInterceptor();
}

咱們隨便自定義一個類便可，這裏主要是將這個類做爲一個bean交給spring容器管理。spring

在sqlSessionFactory中注入

@Bean(name="sessionFactory")
    public SqlSessionFactory sessionFactory(
            @Qualifier("bigDataDataSource") DataSource bigDataDataSource,
            @Qualifier("branchDataSource") DataSource branchDataSource,
            @Qualifier("basicDataSource") DataSource basicDataSource,
            org.apache.ibatis.session.Configuration config) throws Exception{
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        //構造方法，解決動態數據源循環依賴問題。
        MybatisConfiguration configuration = new MybatisConfiguration();
        configuration.addInterceptor(new PaginationInterceptor());
        sessionFactoryBean.setConfiguration(configuration);
        sessionFactoryBean.setConfiguration(config);
        sessionFactoryBean.setDataSource(this.DataSource(bigDataDataSource,branchDataSource, basicDataSource));
        return sessionFactoryBean.getObject();
    }

文中總結

至此，咱們的mybatisplus的分頁插件就好使了。下面給你們提供MyBatis多數據源的解決方案。sql

動態數據源解決方案

數據庫配置文件

咱們項目使用的是yml形式的配置文件，採用的是hikari的數據庫鏈接池。第一步咱們天然是配置多個數據庫源頭。
咱們找到spring的datasource，在下方配置三個數據源。數據庫

spring:
  application:
    name: dynamicDatasource
  datasource:
    test1:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/test1?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
    test2:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/test2?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
    test3:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/test3?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
    hikari:
      leak-detection-threshold: 2000

定義數據源實體類

咱們能夠創建個datasourceBean文件夾專門管理數據源的實體類。
咱們這裏要創建三個實體類。分別對應test1，test2，test3apache

@Configuration
public class Test1DataSourceBean {

    @Value("${spring.datasource.test1.driver-class-name}")
    private String test1Driver;

    @Value("${spring.datasource.test1.url}")
    private String test1Url;

    @Value("${spring.datasource.test1.username}")
    private String test1Username;

    @Value("${spring.datasource.test1.password}")
    private String test1Password;

    @Bean(name="test1DataSource")
    public DataSource test1DataSource() throws Exception{
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setDriverClassName(test1Driver);
        dataSource.setJdbcUrl(test1Url);
        dataSource.setUsername(test1Username);
        dataSource.setPassword(test1Password);
        return dataSource;
    }
}

@Configuration
public class Test2DataSourceBean {

    @Value("${spring.datasource.test2.driver-class-name}")
    private String test2Driver;

    @Value("${spring.datasource.test2.url}")
    private String test2Url;

    @Value("${spring.datasource.test2.username}")
    private String test2Username;

    @Value("${spring.datasource.test2.password}")
    private String test2Password;

    @Bean(name="test2DataSource")
    public DataSource test2DataSource() throws Exception{
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setDriverClassName(test2Driver);
        dataSource.setJdbcUrl(test2Url);
        dataSource.setUsername(test2Username);
        dataSource.setPassword(test2Password);
        return dataSource;
    }
}

@Configuration
public class Test3DataSourceBean {

    @Value("${spring.datasource.test3.driver-class-name}")
    private String test3Driver;

    @Value("${spring.datasource.test3.url}")
    private String test3Url;

    @Value("${spring.datasource.test3.username}")
    private String test3Username;

    @Value("${spring.datasource.test3.password}")
    private String test3Password;

    @Bean(name="test3DataSource")
    public DataSource test3DataSource() throws Exception{
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setDriverClassName(test3Driver);
        dataSource.setJdbcUrl(test3Url);
        dataSource.setUsername(test3Username);
        dataSource.setPassword(test3Password);
        return dataSource;
    }
}

定義一個枚舉類管理數據源

public enum DatabaseType {

    test1("test1", "test1"),
    test2("test2", "test2"),
    test3("test3","test3");

    private String name;
    private String value;

    DatabaseType(String name, String value){
        this.name = name;
        this.value = value;
    }

    public String getName(){
        return name;
    }

    public String getValue(){
        return value;
    }
}

定義一個線程安全的數據源容器

public class DatabaseContextHolder {

    private static final ThreadLocal<DatabaseType> contextHolder = new ThreadLocal<>();

    public static void setDatabaseType(DatabaseType type){
        contextHolder.set(type);
    }

    public static DatabaseType getDatabaseType(){
        return contextHolder.get();
    }
}

定義動態數據源

public class DynamicDataSource extends AbstractRoutingDataSource{

    protected Object determineCurrentLookupKey() {
        return DatabaseContextHolder.getDatabaseType();
    }
}

mybatis配置類

網上的不少文章配置出來都會產生數據源循環依賴的問題，這裏解決了這個問題。安全

@Configuration
@MapperScan(basePackages="cn.test.jichi", sqlSessionFactoryRef="sessionFactory")
public class MybatisConfig {

    /**
     *  @Description:設置動態數據源
     */
    @Bean(name="dynamicDataSource")
    @Primary
    public DynamicDataSource DataSource(
            @Qualifier("test1DataSource") DataSource test1DataSource,
            @Qualifier("test2DataSource") DataSource test2DataSource,
            @Qualifier("test3DataSource") DataSource test3DataSource){
        Map<Object, Object> targetDataSource = new HashMap<>();
        targetDataSource.put(DatabaseType.test1, test1DataSource);
        targetDataSource.put(DatabaseType.test2, test2DataSource);
        targetDataSource.put(DatabaseType.test3, test3DataSource);
        DynamicDataSource dataSource = new DynamicDataSource();
        dataSource.setTargetDataSources(targetDataSource);
        dataSource.setDefaultTargetDataSource(test1DataSource);
        return dataSource;
    }

    /**
     *  @Description:根據動態數據源建立sessionFactory
     */
    @Bean(name="sessionFactory")
    public SqlSessionFactory sessionFactory(
            @Qualifier("test1DataSource") DataSource test1DataSource,
            @Qualifier("test2DataSource") DataSource test2DataSource,
            @Qualifier("test3DataSource") DataSource test3DataSource) throws Exception{
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        //構造方法，解決動態數據源循環依賴問題。
        sessionFactoryBean.setDataSource(this.DataSource(test1DataSource,test2DataSource, test3DataSource));
        return sessionFactoryBean.getObject();
    }
}

提供一個示例

public void testDymnaicDatasource(){
        //不切換數據源默認是本身的。
        System.out.println("-----默認數據源");
        DemoEntity totalCount = demoMapper.getTotalCount();
        String nameCount1 = totalCount.getNameCount();
        String ageCount2 = totalCount.getAgeCount();
        System.out.println("nameCount:"+nameCount1);
        System.out.println("ageCount:"+ageCount2);
        //數據源切換爲branch
        System.out.println("-----數據源爲test2");
        DynamicDataSourceUtils.chooseBranchDataSource();
        Integer nameCount = demoMapper.getNameCount();
        Integer ageCount = demoMapper.getAgeCount();
        System.out.println("nameCount:"+nameCount);
        System.out.println("ageCount:"+ageCount);
        //數據源爲basic
        System.out.println("-----數據源爲test3");
        DynamicDataSourceUtils.chooseBasicDataSource();
        Integer ageCount1 = demoMapper.getAgeCount();
        System.out.println("ageCount:"+ageCount1);

    }