JAVA动态连接数据库

package com.springcloud.web.config.dataSource;

import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
public class BaseDBConfig {
    private String username;
    private String url;
    private String password;
    private String driverClassName;
}

package com.springcloud.web.config.dataSource;

import lombok.Getter;
import lombok.Setter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@Getter
@Setter
@Configuration
@ConfigurationProperties(prefix = "spring.datasource")
public class DBDefaultConfig extends BaseDBConfig{
}

package com.springcloud.web.config.dataSource;

import lombok.Getter;
import lombok.Setter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@Getter
@Setter
@Configuration
@ConfigurationProperties(prefix = "db.dev")
public class DBDevConfig extends BaseDBConfig {
}

自定义动态数据库
通过继承AbstractRoutingDataSource来实现

package com.springcloud.web.config.dataSource;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class DynamicDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDataSourceContextHolder.getDataSourceKey();
    }
}

package com.springcloud.web.config.dataSource;

public class DynamicDataSourceContextHolder {
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
    public static void setDataSourceKey(String key){
        contextHolder.set(key);
    }
    public static String getDataSourceKey(){
        return contextHolder.get();
    }

    public static void clearDataSourceKey(){
        contextHolder.remove();
    }
}

DynamicDataSourceConfig 这个类很重要，在dataSourceMap()这个方法中初始化了需要使用的数据库集合，通过key值来获取需要使用的数据库

package com.springcloud.web.config.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;

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

@Configuration
public class DynamicDataSourceConfig {

    @Autowired
    DBDefaultConfig dbDefaultConfig;
    @Autowired
    DBDevConfig dbDevConfig;

    private DataSource createDataSource(BaseDBConfig dbConfig){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(dbConfig.getDriverClassName());
        dataSource.setUsername(dbConfig.getUsername());
        dataSource.setPassword(dbConfig.getPassword());
        return dataSource;
    }

	//需要切换的数据库集合,通过key值来获取需要使用的数据库
    public Map<Object,Object> dataSourceMap(){
        Map<Object,Object> sourceMap = new HashMap<>();
        sourceMap.put("dev",createDataSource(dbDevConfig));
        sourceMap.put("default",createDataSource(dbDefaultConfig));
        return sourceMap;
    }

    @Bean("DynamicDataSource")
    public DynamicDataSource dataSource(){
        DynamicDataSource dataSource = new DynamicDataSource();
        //需要设置默认数据库,否则在没有请求时，不知道连接哪个数据库，会报数据库连接错误
        dataSource.setDefaultTargetDataSource(createDataSource(dbDefaultConfig));
        dataSource.setTargetDataSources(dataSourceMap());
        return dataSource;
    }

    @Bean("jdbcTemplate")
    public NamedParameterJdbcTemplate jdbcTemplate(@Qualifier("DynamicDataSource") DynamicDataSource dataSource){
        return new NamedParameterJdbcTemplate(new JdbcTemplate(dataSource));
    }
}

测试数据库连接

package com.springcloud.web.controller;

import com.springcloud.web.config.dataSource.DynamicDataSourceContextHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Map;

@RestController("/api")
public class DataSourceController {

    @Autowired
    UserMapper userMapper;

    @GetMapping("/dataSource")
    public Map<String,Object> testDataSourceType(String key){
        DynamicDataSourceContextHolder.setDataSourceKey(key);
        return userMapper.getUser();
    }
}

在查询数据前需要调用 DynamicDataSourceContextHolder.setDataSourceKey(key)方法切换数据库,可以在拦截器或者过滤器中调用。这里传入参数key值为dev或者default，根据传入的key值不同，拿到对应数据库的user值。我在DynamicDataSourceConfig的dataSourceMap()方法中只设置了这两个key值，如果需要使用其他的数据库，只需要在这个方法中添加即可。