Spring simple analog integrated Mybatis

Overall package structure

 

 

 

We need a preferred interface class, the equivalent Mapper

package com.fh.mybatis.dao;

import com.fh.mybatis.config.Select;

public interface CardDao {

    @Select("select * from demo")
    void list(String mess);
}

Then annotation class interface used in class

package com.fh.mybatis.config;

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

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Select {

    String value() default "";
}

After a required class, the proxy object to provide a method and implementation of specific

Because the interface implementation class FactoryBean class, instantiated, it returns the object returned by the method getObject

package com.fh.mybatis.config;

import org.springframework.beans.factory.FactoryBean;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class MyFactoryBean implements FactoryBean, InvocationHandler {

    private Class aClass;

    public MyFactoryBean(Class cla){
        this.aClass = cla;
    }


    @Override
    public Object getObject() {
        Class[] classes = new Class[] {aClass};
        Object object = Proxy.newProxyInstance(this.getClass().getClassLoader(), classes, this);
        return object;
    }

    @Override
    public Class<?> getObjectType() {
        return aClass;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Exception{
        Method list = proxy.getClass().getInterfaces()[0].getMethod(method.getName(), String.class);
        Select select = list.getDeclaredAnnotation(Select.class);
        System.out.println(select.value());
        return null;
    }
}

Then, you need to add an object instance to the Spring container, but the Spring container object is created by BeanDefinition out, so you need to add a class to register BeanDefinitionde

package com.fh.mybatis;

import com.fh.mybatis.config.LubanScan;
import com.fh.mybatis.config.MyFactoryBean;
import com.fh.mybatis.dao.CardDao;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.annotation.MergedAnnotation;
import org.springframework.core.annotation.MergedAnnotations;
import org.springframework.core.type.AnnotationMetadata;

public class MyImportBeanDefinitionRegister implements ImportBeanDefinitionRegistrar {


    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
        MergedAnnotations annotations = importingClassMetadata.getAnnotations();
        MergedAnnotation<LubanScan> lubanScanMergedAnnotation = annotations.get(LubanScan.class);
        String value = lubanScanMergedAnnotation.getString("value");
        System.out.println("----------");
        System.out.println(value);
        BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(CardDao.class);
        GenericBeanDefinition beanDefinition =(GenericBeanDefinition) builder.getBeanDefinition();
        beanDefinition.getConstructorArgumentValues().addGenericArgumentValue("com.fh.mybatis.dao.CardDao");
        beanDefinition.setBeanClass(MyFactoryBean.class);
        registry.registerBeanDefinition("cardDao",beanDefinition);
    }
}

Finally add a comment, to deal with on top of the class

package com.fh.mybatis.config;

import com.fh.mybatis.MyImportBeanDefinitionRegister;
import org.springframework.context.annotation.Import;

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

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Import(MyImportBeanDefinitionRegister.class)
public @interface LubanScan {

    String value() default "";
}

And then test it, add a configuration class

package com.fh.mybatis.config;

import org.springframework.context.annotation.Configuration;

@Configuration
@LubanScan("com.fh")
public class MybatisConfig {
}

Finally Gets an object from the container, and then call the interface method, print sql statement