javaweb(不用spring) servlet 整合原生 dubbo api 生产者消费者示例

avatar 2021年08月29日19:11:27 7 2964 views
博主分享免费Java教学视频，B站账号：Java刘哥 ，长期提供技术问题解决、项目定制：本站商品点此

本文介绍在不使用spring的情况下，javaweb整合dubbo的示例。

完整代码：https://github.com/saysky/saysky-dubbo-study-example/tree/master/dubbo-javaweb-example

代码结构如下

下面主要贴一些核心代码，完整代码见github，里面包括javaweb、spring和springboot整合dubbo

一、生产者 API 和 Impl

先看下生产者api模块和生产者代码实现的代码结构

 

1、User类

package com.liuyanzhao.provider.api.entity;

import java.io.Serializable;

/**
 * 用户实体类，用于演示
 * @author 言曌
 * @date 2021/8/29 11:23 上午
 */
public class User implements Serializable {

    private Integer id;
    private String name;
    private String sex;

    public User() {
    }

    public User(Integer id, String name, String sex) {
        this.id = id;
        this.name = name;
        this.sex = sex;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }
}

 

2、UserService

package com.liuyanzhao.provider.api.service;

import com.liuyanzhao.provider.api.entity.User;

import java.sql.SQLException;
import java.util.List;

/**
 * 用户服务接口
 *
 * @author 言曌
 * @date 2021/8/29 11:24 上午
 */

public interface UserService {

    /**
     * 查询所有用户
     *
     * @return
     */
    List<User> findAll() throws Exception;

    /**
     * 根据id查询
     *
     * @return
     */
    User findById(Integer id) throws Exception;
}

 

3、UserServiceImpl

package com.liuyanzhao.provider.impl.service;

import com.liuyanzhao.provider.impl.dao.UserDao;
import com.liuyanzhao.provider.api.entity.User;
import com.liuyanzhao.provider.api.service.UserService;

import java.util.List;

/**
 * 用户服务实现
 *
 * @author 言曌
 * @date 2021/8/29 11:43 上午
 */
public class UserServiceImpl implements UserService {

    private UserDao userDao = new UserDao();

    @Override
    public List<User> findAll() throws Exception {
        return userDao.findAll();
    }

    @Override
    public User findById(Integer id) throws Exception {
        return userDao.findById(id);
    }
}

 

4、UserDao

package com.liuyanzhao.provider.impl.dao;

import com.liuyanzhao.consumer.impl.util.DBUtil;
import com.liuyanzhao.provider.api.entity.User;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * 用户数据访问层，模拟从数据库取数据
 *
 * @author 言曌
 * @date 2021/8/29 11:26 上午
 */

public class UserDao {

    /**
     * 获取所有用户
     *
     * @return
     */
    public List<User> findAll() throws SQLException {
        List<User> userList = new ArrayList<User>();
        DBUtil dbUtil = new DBUtil();
        ResultSet resultSet = dbUtil.query("SELECT * FROM user");
        while (resultSet.next()) {
            Integer id = resultSet.getInt("id");
            String name = resultSet.getString("name");
            String sex = resultSet.getString("sex");
            userList.add(new User(id, name, sex));
        }
        return userList;
    }

    /**
     * 根据用户id查询用户
     *
     * @return
     */
    public User findById(Integer id) throws SQLException {
        DBUtil dbUtil = new DBUtil();
        ResultSet resultSet = dbUtil.query("SELECT * FROM user where id = " + id);
        while (resultSet.next()) {
            String name = resultSet.getString("name");
            String sex = resultSet.getString("sex");
            return new User(id, name, sex);
        }
        return null;
    }


}

 

5、DBUtil

package com.liuyanzhao.provider.impl.util;

import java.sql.*;

/**
 * 数据库查询工具类 for MySQL
 *
 * @author 言曌
 * @date 2021/8/29 11:34 上午
 */
public class DBUtil {
    private Connection conn;
    private Statement stmt;
    private ResultSet rs;

    private final String DRIVER = "com.mysql.cj.jdbc.Driver";
    private final String URL = "jdbc:mysql://127.0.0.1:3306/dubbo_study_example?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC";
    private final String USERNAME = "root";
    private final String PASSWWORD = "123456";


    /**
     * 获得数据库连接
     *
     * @return
     */
    private boolean getConnection() {
        try {
            Class.forName(DRIVER);
            conn = DriverManager.getConnection(URL, USERNAME, PASSWWORD);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 执行SQL
     *
     * @param sql
     * @return
     */
    public ResultSet query(String sql) {
        if (getConnection()) {
            try {
                stmt = (Statement) conn.createStatement();
                rs = stmt.executeQuery(sql);
                return rs;
            } catch (SQLException e) {
                e.printStackTrace();
                return null;
            }
        } else {
            return null;
        }
    }

    /**
     * 执行更新SQL
     *
     * @param sql
     * @return
     */
    public int update(String sql) {
        if (getConnection()) {
            try {
                stmt = conn.createStatement();
                int flag = stmt.executeUpdate(sql);
                return flag;
            } catch (Exception e) {
                e.printStackTrace();
                return -1;
            }
        } else {
            return -1;
        }
    }

    /**
     * 关闭连接
     *
     * @return
     */
    public boolean closeAll() {
        try {
            if (rs != null) {
                rs.close();
            }
            if (stmt != null) {
                stmt.close();
            }
            if (conn != null) {
                conn.close();
            }
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
}

 

用户表

 

关于pom.xml这里就不贴了，impl 需要引入 api

 

二、生产者 Dubbo 整合，服务注册

代码结构如下

 

1、pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>dubbo-javaweb-demo</artifactId>
        <groupId>com.liuyanzhao</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <packaging>war</packaging>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>6</source>
                    <target>6</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <artifactId>dubbo-javaweb-example-provider-web</artifactId>

    <dependencies>
        <!--        impl里面包含了api-->
        <dependency>
            <groupId>com.liuyanzhao</groupId>
            <artifactId>dubbo-javaweb-example-provider-impl</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <!--        servlet-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>3.0-alpha-1</version>
            <scope>provided</scope>
        </dependency>

        <!--        log4j日志-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.16</version>
        </dependency>

        <!--        json转换，用于web模块-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.72</version>
        </dependency>


        <!--  整合dubbo和nacos     -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.7.8</version>
            <!-- 原生API不引用spring-->
            <exclusions>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-context</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
            <version>1.2.1</version>
        </dependency>
        
    </dependencies>

</project>

 

2、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
         http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

    <listener>
        <listener-class>com.liuyanzhao.listener.DubboProviderListener</listener-class>
    </listener>

    <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>classpath:log4j.properties</param-value>
    </context-param>


    <servlet>
        <servlet-name>ProviderServlet</servlet-name>
        <servlet-class>com.liuyanzhao.servlet.ProviderServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ProviderServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

 

3、DubboProviderListener

主要作用是项目启动时调用，将我们的 UserService 和 RoleService 作为 dubbo 服务注册到 Nacos 中

package com.liuyanzhao.listener;

import com.liuyanzhao.consumer.impl.service.RoleServiceImpl;
import com.liuyanzhao.consumer.impl.service.UserServiceImpl;
import com.liuyanzhao.provider.api.service.RoleService;
import com.liuyanzhao.provider.api.service.UserService;
import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.config.ServiceConfig;
import org.apache.dubbo.config.bootstrap.DubboBootstrap;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * @author 言曌
 * @date 2021/8/29 1:42 下午
 */

public class DubboProviderListener implements ServletContextListener {

    /**
     * 项目启动时加载
     *
     * @param sce
     */
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        // 定义服务
        ServiceConfig<UserServiceImpl> userService = new ServiceConfig<UserServiceImpl>();
        userService.setInterface(UserService.class);
        userService.setRef(new UserServiceImpl());
        userService.setGroup("provider");
        userService.setId(UUID.randomUUID().toString());

        ServiceConfig<RoleServiceImpl> roleService = new ServiceConfig<RoleServiceImpl>();
        roleService.setInterface(RoleService.class);
        roleService.setRef(new RoleServiceImpl());
        roleService.setGroup("provider");
        roleService.setId(UUID.randomUUID().toString());


        List<ServiceConfig> services = new ArrayList<ServiceConfig>();
        services.add(roleService);
        services.add(userService);

        DubboBootstrap bootstrap = DubboBootstrap.getInstance();
        // 设置应用名
        bootstrap.application(new ApplicationConfig("provider-demo"))
                // 设置注册中心
                .registry(new RegistryConfig("nacos://127.0.0.1:8848"))
                // 设置需要注册的服务
                .services(services).start();

        System.out.println("========> provider finish register services");
    }


    @Override
    public void contextDestroyed(ServletContextEvent sce) {

    }
}

 

4、配置tomcat启动项目

 

5、然后查看 nacos ，可以看到2个服务

 

三、消费者

消费者这里主要是调用一下生产者的2个服务，代码会简单点

代码结构如下

1、pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>dubbo-javaweb-demo</artifactId>
        <groupId>com.liuyanzhao</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>
    <artifactId>dubbo-javaweb-example-consumer</artifactId>


    <dependencies>
        <!--        servlet-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>3.0-alpha-1</version>
            <scope>provided</scope>
        </dependency>
        <!--        生产者api-->
        <dependency>
            <groupId>com.liuyanzhao</groupId>
            <artifactId>dubbo-javaweb-example-provider-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <!--        dubbo和nacos-->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.7.8</version>
            <!-- 原生API不引用spring-->
            <exclusions>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-context</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
            <version>1.2.1</version>
        </dependency>
    </dependencies>
</project>

 

2、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
         http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

    <listener>
        <listener-class>com.liuyanzhao.listener.DubboConsumerListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>ConsumerServlet</servlet-name>
        <servlet-class>com.liuyanzhao.servlet.ConsumerServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>ConsumerServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

 

3、DubboConsumerListener

项目启动时调用，设置需要发现的服务

package com.liuyanzhao.listener;

import com.liuyanzhao.provider.api.service.RoleService;
import com.liuyanzhao.provider.api.service.UserService;
import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.ReferenceConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.config.bootstrap.DubboBootstrap;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import java.util.ArrayList;
import java.util.List;

/**
 * 消费者发现服务
 *
 * @author 言曌
 * @date 2021/8/29 1:42 下午
 */

public class DubboConsumerListener implements ServletContextListener {

    /**
     * 项目启动时加载
     *
     * @param sce
     */
    public void contextInitialized(ServletContextEvent sce) {
        // 定义reference
        ReferenceConfig<UserService> userReference = new ReferenceConfig();
        userReference.setInterface(UserService.class);
        userReference.setGroup("provider");

        ReferenceConfig<RoleService> roleReference = new ReferenceConfig();
        roleReference.setInterface(RoleService.class);
        roleReference.setGroup("provider");


        List<ReferenceConfig> references = new ArrayList<ReferenceConfig>();
        references.add(userReference);
        references.add(roleReference);

        DubboBootstrap bootstrap = DubboBootstrap.getInstance();
        // 设置应用名
        bootstrap.application(new ApplicationConfig("consumer-demo"))
                // 设置注册中心
                .registry(new RegistryConfig("nacos://127.0.0.1:8848"))
                // 设置需要引用的dubbo服务
                .references(references).start();

        System.out.println("========> consumer finish discover services");
    }


    public void contextDestroyed(ServletContextEvent sce) {

    }
}

 

4、ConsumerServlet

测试Servlet，用来判断是否能调用UserService和RoleService

package com.liuyanzhao.servlet;

import com.alibaba.fastjson.JSON;
import com.liuyanzhao.provider.api.entity.Role;
import com.liuyanzhao.provider.api.entity.User;
import com.liuyanzhao.provider.api.service.RoleService;
import com.liuyanzhao.provider.api.service.UserService;
import org.apache.dubbo.config.ReferenceConfig;
import org.apache.dubbo.config.utils.ReferenceConfigCache;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

/**
 * ConsumerServlet
 *
 * @author 言曌
 * @date 2021/8/29 11:06 上午
 */
public class ConsumerServlet extends HttpServlet {


    /**
     * 响应一句话
     *
     * @param req
     * @param resp
     * @throws ServletException
     * @throws IOException
     */
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        StringBuilder content = new StringBuilder("dubbo-javaweb-example-consumer:\n");
        resp.setContentType("application/json;charset=UTF-8");


        // 调用 UserService
        try {
            ReferenceConfig<UserService> userReference = new ReferenceConfig();
            userReference.setInterface(UserService.class);
            userReference.setGroup("provider");
            UserService userService = ReferenceConfigCache.getCache().get(userReference);
            List<User> userList = userService.findAll();
            content.append(JSON.toJSONString(userList)).append("\n");
        } catch (Exception e) {
            e.printStackTrace();
            resp.getWriter().write("userService连接失败\n" + e.getMessage() + "\n");
        }

        // 调用 RoleService
        try {

            ReferenceConfig<RoleService> roleReference = new ReferenceConfig();
            roleReference.setInterface(RoleService.class);
            roleReference.setGroup("provider");

            RoleService roleService = ReferenceConfigCache.getCache().get(roleReference);
            List<Role> roleList = roleService.findAll();
            content.append(JSON.toJSONString(roleList)).append("\n");
        } catch (Exception e) {
            e.printStackTrace();
            resp.getWriter().write("roleService连接失败\n" + e.getMessage() + "\n");
        }


        resp.getWriter().write(content.toString());
    }


}

 

5、配置tomcat，查看浏览器看效果

成功调用

 

历史上的今天
八月
29日
  • 微信
  • 交流学习，资料分享
  • weinxin
  • 个人淘宝
  • 店铺名：言曌博客咨询部

  • (部分商品未及时上架淘宝)
avatar

发表评论

avatar 登录者：匿名
匿名评论，评论回复后会有邮件通知

  

已通过评论：1   待审核评论数：0
  1. avatar 雷达探币
    回复 2021年11月09日 02:07:04

    每天醒来，敲醒自己的不是钟声，而是梦想