Google Guice Annotation Binding

    Google Guice提供Annotation Binding，可以使用注解来对依赖进行绑定并同时进行赋值。

 

    一。@DriverClassName

 

package com.template.guice;

import com.google.inject.BindingAnnotation;

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

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Created by IntelliJ IDEA.
 * User: Zhong Gang
 * Date: 11-8-6
 * Time: 下午3:23
 */
@BindingAnnotation
@Target({ METHOD, CONSTRUCTOR, FIELD })
@Retention(RUNTIME)
public @interface DriverClassName {
}

 

    二。@Username

 

package com.template.guice;

import com.google.inject.BindingAnnotation;

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

import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Created by IntelliJ IDEA.
 * User: Zhong Gang
 * Date: 11-8-6
 * Time: 下午3:23
 */
@BindingAnnotation
@Target({ METHOD, CONSTRUCTOR, FIELD })
@Retention(RUNTIME)
public @interface Username {
}

 

    三。@Url

 

package com.template.guice;

import com.google.inject.BindingAnnotation;

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

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Created by IntelliJ IDEA.
 * User: Zhong Gang
 * Date: 11-8-6
 * Time: 下午3:23
 */
@BindingAnnotation
@Target({ METHOD, CONSTRUCTOR, FIELD })
@Retention(RUNTIME)
public @interface Url {
}

 

    四。@Password

 

package com.template.guice;

import com.google.inject.BindingAnnotation;

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

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Created by IntelliJ IDEA.
 * User: Zhong Gang
 * Date: 11-8-6
 * Time: 下午3:23
 */
@BindingAnnotation
@Target({ METHOD, CONSTRUCTOR, FIELD })
@Retention(RUNTIME)
public @interface Password {
}

 

    五。DBConnection

 

package com.template.guice;

import com.google.inject.Inject;
import com.google.inject.Singleton;

/**
 * Created by IntelliJ IDEA.
 * User: Zhong Gang
 * Date: 11-8-6
 * Time: 下午3:28
 */
@Singleton
public class Connection {

    @Inject
    @DriverClassName
    private String driverClassName;

    @Inject
    @Url
    private String url;

    @Inject
    @Username
    private String username;

    @Inject
    @Password
    private String password;

    public String driverClassName() {
        return driverClassName;
    }

    public String url() {
        return url;
    }

    public String username() {
        return username;
    }

    public String password() {
        return password;
    }
}

 

    六。ConnectionModule

 

package com.template.guice;

import com.google.inject.Binder;
import com.google.inject.Module;

/**
 * Created by IntelliJ IDEA.
 * User: Zhong Gang
 * Date: 11-8-6
 * Time: 下午3:32
 */
public class ConnectionModule implements Module {

    @Override
    public void configure(Binder binder) {

        binder.bind(String.class).annotatedWith(DriverClassName.class).toInstance("com.mysql.jdbc.Driver");
        binder.bind(String.class).annotatedWith(Url.class).toInstance("jdbc:mysql://localhost:3306/demo");
        binder.bind(String.class).annotatedWith(Username.class).toInstance("root");
        binder.bind(String.class).annotatedWith(Password.class).toInstance("root");

    }
}

 

    七。Main

 

package com.template.guice;

import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Module;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Created by IntelliJ IDEA.
 * User: Zhong Gang
 * Date: 11-8-6
 * Time: 下午3:36
 */
public class Main {

    public static final Logger logger = LoggerFactory.getLogger(Main.class);

    public static void main(String[] args) {
        Module module = new ConnectionModule();
        Injector injector = Guice.createInjector(module);
        Connection instance1 = injector.getInstance(Connection.class);
        Connection instance2 = injector.getInstance(Connection.class);

        logger.info("instance1 is " + instance1);
        logger.info("instance2 is " + instance2);
        logger.info("instance1's hashcode is " + instance1.hashCode());
        logger.info("instance2's hashcode is " + instance2.hashCode());
        logger.info("driverClassName is " + instance1.driverClassName());
        logger.info("url is " + instance1.url());
        logger.info("username is " + instance1.username());
        logger.info("password is " + instance1.password());
    }
}

 

    八。运行结果