动态数据源

package com.backstage.lddome.config;

import com.backstage.lddome.datasource.DynamicDataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import sun.security.krb5.Config;

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

/**
 * 多数据源配置类
 * Created by pure on 2018-05-06.
 */
@Configuration
public class DataSourceConfig {
    //数据源1
    @Bean(name = "datasource1")
    @ConfigurationProperties(prefix = "spring.datasource.db1") // application.properteis中对应属性的前缀
    public DataSource dataSource1() {
        return DataSourceBuilder.create().build();
    }

    //数据源2
    @Bean(name = "datasource2")
    @ConfigurationProperties(prefix = "spring.datasource.db2") // application.properteis中对应属性的前缀
    public DataSource dataSource2() {
        return DataSourceBuilder.create().build();
    }

    /**
     * 动态数据源: 通过AOP在不同数据源之间动态切换
     *
     * @return
     */
    @Primary
    @Bean(name = "dynamicDataSource")
    public DataSource dynamicDataSource() {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        // 默认数据源
        dynamicDataSource.setDefaultTargetDataSource(dataSource1());
        // 配置多数据源
        Map<Object, Object> dsMap = new HashMap();
        dsMap.put("datasource1", dataSource1());
        dsMap.put("datasource2", dataSource2());

        dynamicDataSource.setTargetDataSources(dsMap);
        return dynamicDataSource;
    }

    /**
     * 配置@Transactional注解事物
     *
     * @return
     */
    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dynamicDataSource());
    }
}  

package com.backstage.lddome.aspect;

import com.backstage.lddome.datasource.DS;
import com.backstage.lddome.datasource.DataSourceContextHolder;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

import java.io.*;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLConnection;

/**
 * 自定义注解 + AOP的方式实现数据源动态切换。
 * Created by pure on 2018-05-06.
 */
@Aspect
@Component
public class DynamicDataSourceAspect {

    @Before("@annotation(ds)")
    public void beforeSwitchDS(JoinPoint point, DS ds) {
        //获得当前访问的class
        Class<?> className = point.getTarget().getClass();
        //获得访问的方法名
        String methodName = point.getSignature().getName();
        //得到方法的参数的类型
        Class[] argClass = ((MethodSignature) point.getSignature()).getParameterTypes();
        String dataSource = DataSourceContextHolder.DEFAULT_DS;
        try {
            // 得到访问的方法对象
            Method method = className.getMethod(methodName, argClass);
            // 判断是否存在@DS注解
            if (method.isAnnotationPresent(DS.class)) {
                DS annotation = method.getAnnotation(DS.class);
                // 取出注解中的数据源名
                dataSource = annotation.value();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 切换数据源
        DataSourceContextHolder.setDB(dataSource);
    }

    @After("@annotation(ds)")
    public void afterSwitchDS(JoinPoint point, DS ds) {
        DataSourceContextHolder.clearDB();
    }


    public static void main(String[] args) {

        String path = "f:\\haha";
        try {
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            URL url = new URL("http://imgs.jinxiaoersh.com/1576219511646f0d52580401241b5aed3ccaae3e72880.png");
            URLConnection urlConnection = url.openConnection();
            InputStream inputStream = urlConnection.getInputStream();


            String file = url.getFile();
            System.out.println(file);
//            FileInputStream fileInputStream = new FileInputStream(url);
            int len = -1;
            //循环读取
            byte[] b = new byte[1024];
            while ((len = inputStream.read(b)) != -1) {
                    byteArrayOutputStream.write(b, 0, len);
                }
            //返回byteArrayOutputStream数组
            byte[] bytes = byteArrayOutputStream.toByteArray();
            new DataOutputStream(new FileOutputStream(path)).write(bytes);
        } catch (Exception e) {
            System.out.println(e);
        }


    }
}

package com.backstage.lddome.datasource;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * 自定义注解
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface DS {
    String value() default "datasource1";
}

package com.backstage.lddome.datasource;

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

/**
 * Created by pure on 2018-05-06.
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        System.out.println("数据源为" + DataSourceContextHolder.getDB());
        return DataSourceContextHolder.getDB();
    }
}

package com.backstage.lddome.datasource;

import java.io.*;

/**
 * Created by pure on 2018-05-06.
 */
public class DataSourceContextHolder {
    /**
     * 默认数据源
     */
    public static final String DEFAULT_DS = "datasource1";
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

    // 设置数据源名
    public static void setDB(String dbType) {
        contextHolder.set(dbType);
    }

    // 获取数据源名
    public static String getDB() {
        return (contextHolder.get());
    }

    // 清除数据源名
    public static void clearDB() {
        contextHolder.remove();
    }


    public static Object copy(Object orig) throws IOException, ClassNotFoundException {
        Object obj = null;
            // Write the object out to a byte array
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream out = new ObjectOutputStream(bos);
            out.writeObject(orig);
            out.flush();
            out.close();

            // Make an input stream from the byte array and read
            // a copy of the object back in.
            ObjectInputStream in = new ObjectInputStream(
                    new ByteArrayInputStream(bos.toByteArray()));
            obj = in.readObject();

        return obj;
    }
}