SpringMVC主从数据库切换

配置文件中添加数据库配置信息

    
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        
    
    
    
        .......
     
    
    
    
        
            
        
        
    
    
    
        
        .....
        
            
                
                    
                        
                            dialect=mysql
                            reasonable=true
                        
                    
                
            
         
    
    

自定义注解

可以添加在方法上指定是走主库还是从库，不添加则根据方法名选择

/**
 * 
 * @author Honva
 * @Description 数据库切换标记注解
 */
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
    public String value();
}

数据库适配类

/**
 * 
 * @author Honva
 * @Description 数据源
 */
public class DbContextHolder {
    public static final String WRITE = "write";
    public static final String READ = "read";
    private  static ThreadLocal dataSource = new ThreadLocal();
    
    public static void set(String name){
        dataSource.set(name);
    }
    public static String get(){
        return dataSource.get();
    }
    public static void remove(){
        dataSource.remove();
    }
}

自定义切面

自定义切面入口，在执行方法前先判断方法名，再选择主从库

/**
 * @author Honva
 * @Description 数据库切换切面
 */
@Aspect
@Component
public class DbAspect {
    private String PRE_PAGING = "paging";
    private String PRE_GET = "get";
    private String PRE_FIND = "find";

    @Before("execution(* cn.manager.mapper..*.*(..))")
    public void dbAspect(JoinPoint point) throws Exception {
        MethodSignature s = (MethodSignature) point.getSignature();
        Method method = s.getMethod();
        String methodName = method.getName();
        DataSource dataSource = method.getAnnotation(DataSource.class);
        if (dataSource != null) {
            DbContextHolder.set(dataSource.value());
        } else if (methodName.startsWith(PRE_PAGING) || methodName.startsWith(PRE_GET)
                || methodName.startsWith(PRE_FIND)) {
            DbContextHolder.set(DbContextHolder.READ);
        } else {
            DbContextHolder.set(DbContextHolder.WRITE);
        }
    }
}

动态数据库切换类（重点类）

/**
 * 
 * @author Honva
 * @Description 动态数据源切换
 */
public class DynamicDataSource extends AbstractRoutingDataSource{
    
    @Override
    protected Object determineCurrentLookupKey() {
        String key = DbContextHolder.get();
        try {
            if(key==null || key.equals(DbContextHolder.WRITE)){
                return null;
            }
            if(key.equals(DbContextHolder.READ)){
                try {
                    Field field = this.getClass().getSuperclass().getDeclaredField("targetDataSources");    field.setAccessible(true);
                    @SuppressWarnings("unchecked")
                    Map targetDataSources = (Map) field.get(this);
                    if(targetDataSources.isEmpty()){
                        return DbContextHolder.WRITE;
                    }
                    List