SpringBoot 08: SpringBoot综合使用 MyBatis, Dubbo, Redis

业务背景

Student表

CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) COLLATE utf8_bin DEFAULT NULL,
  `phone` varchar(11) COLLATE utf8_bin DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

两个业务功能

针对上述student表, 综合应用springboot, mybatis, dubbo, redis实现如下两个业务功能

1. 注册学生

• 要求:

• 注册接口定义为：int saveStudent(Student student)

• 利用传入的学生的手机号注册，手机号必须唯一

• 如果已经存在了手机号， 注册失败， 返回2

• 如果手机号为空，注册失败，返回-1

• 注册成功，返回0

2. 查询学生

• 要求：
• 查询接口定义为：Student queryStudent(Integer id)
• 根据id查询目标学生
• 先到redis查询学生，如果redis没有，从数据库查询
• 如果数据库有，把查询到的学生放入到redis，返回该学生，后续再次查询这个学生应该从redis就能获取到
• 如果数据库也没有目标学生，返回空

其他要求

• 关于Dubbo
  • 要求使用dubbo框架，addStudent, queryStudent是由服务提供者实现的
  • 消费者可以是一个Controller，调用提供者的两个方法， 实现学生的注册和查询
• 关于前端页面
  • 页面使用html, ajax, jquery
  • 通过postman发送post请求，来注册学生
  • 通过html页面上的form表单，提供文本框输入id, 进行查询
  • html, jquery.js都放到springboot项目的resources/static目录中

编程实现

项目结构

• 分布式总体项目结构

• 公共接口项目结构

• 服务提供者项目结构

• 消费者项目结构

dubbo的公共接口项目

注意该项目为普通的maven项目即可

实体类

package com.example.demo.model;

import java.io.Serializable;

public class Student implements Serializable {
    private static final long serialVersionUID = -3272421320600950226L;
    private Integer id;
    private String name;
    private String phone;
    private Integer age;

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", phone='" + phone + '\'' +
                ", age=" + age +
                '}';
    }

    //防止缓存穿透，可以获取默认学生(学生信息故意设置不合法，后期在redis中一眼就能看出来是异常数据)，填充到redis中
    public static Student getDefaultStudent(){
        Student student = new Student();
        student.setId(-1);
        student.setName("-");
        student.setPhone("-");
        student.setAge(0);
        return student;
    }

    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 getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Student(Integer id, String name, String phone, Integer age) {
        this.id = id;
        this.name = name;
        this.phone = phone;
        this.age = age;
    }

    public Student() {
    }
}

提供的服务接口定义

package com.example.demo.service;

import com.example.demo.model.Student;

public interface StudentService {
    //保存学生信息
    int saveStudent(Student student);

    //根据id，查询学生信息
    Student queryStudent(Integer id);
}

dubbo的服务提供者项目

注意：该项目为springboot项目，且在起步依赖里要勾选web(web依赖可以不选), redis, mysql, mybatis的起步依赖

项目配置

• 额外在pom.xml里手动加入对公共接口项目以及dubbo和zookeeper的依赖

        
        <dependency>
            <groupId>com.example.demogroupId>
            <artifactId>demo-apiartifactId>
            <version>1.0.0version>
        dependency>

        
        <dependency>
            <groupId>org.apache.dubbogroupId>
            <artifactId>dubbo-spring-boot-starterartifactId>
            <version>2.7.8version>
        dependency>


        
        <dependency>
            <groupId>org.apache.dubbogroupId>
            <artifactId>dubbo-dependencies-zookeeperartifactId>
            <version>2.7.8version>
            <type>pomtype>
            <exclusions>
                
                <exclusion>
                    <artifactId>slf4j-log4j12artifactId>
                    <groupId>org.slf4jgroupId>
                exclusion>
            exclusions>
        dependency>

• 配置application.properties文件

########################### 配置dubbo
#配置提供的服务名称
dubbo.application.name=student-service-provider

#配置需要扫描的包
dubbo.scan.base-packages=com.example.demo.service

#配置注册中心
dubbo.registry.address=zookeeper://127.0.0.1:2181

########################### 配置redis
#redis服务的ip
spring.redis.host=127.0.0.1

#redis服务的端口
spring.redis.port=6379

########################### mybatis配置
#mybatis中mapper文件编译到的资源路径
mybatis.mapper-locations=classpath:mapper/*.xml

#mybatis日志输出
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

############################ 数据源配置
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://数据库服务器ip:3306/数据库名?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8
spring.datasource.username=XXX
spring.datasource.password=YYY

dao层

• dao接口

package com.example.demo.dao;

import com.example.demo.model.Student;
import org.apache.ibatis.annotations.Param;

public interface StudentDao {
    //以手机号作为查询条件，判断学生是否存在
    Student queryStudentByPhone(@Param("phone") String phone);

    //保存新创建的学生信息
    int saveStudent(Student student);

    //根据学生id，查询学生信息
    Student queryStudentById(@Param("id") Integer id);
}

• dao接口对应的xml文件, 位于resources/mapper目录下，这里将dao接口和dao.xml文件分开管理

mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.demo.dao.StudentDao">
    
    <select id="queryStudentByPhone" parameterType="string" resultType="com.example.demo.model.Student">
        select id, name, age, phone from student where phone = #{phone}
    select>

    
    <insert id="saveStudent" parameterType="com.example.demo.model.Student">
        insert into student(name, age, phone) values(#{name}, #{age}, #{phone})
    insert>

    
    <select id="queryStudentById" parameterType="int" resultType="com.example.demo.model.Student">
        select id, name, age, phone from student where id = #{id}
    select>

mapper>

• 实现公共接口工程里对外提供的服务

package com.example.demo.service.impl;

import com.example.demo.dao.StudentDao;
import com.example.demo.model.Student;
import com.example.demo.service.StudentService;
import org.apache.dubbo.config.annotation.DubboService;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import javax.annotation.Resource;

@DubboService(interfaceClass = StudentService.class, version = "1.0.0", timeout = 5000)
public class StudentServiceImpl implements StudentService {

    @Resource
    private StudentDao studentDao;

    @Resource
    private RedisTemplate redisTemplate;

    //保存新创建的学生
    @Override
    public int saveStudent(Student student) {
        int saveResult = 0;//表示保存学生信息的结果：1/添加成功 -1:手机号为空 2:手机号码重复
        if(student.getPhone() == null){
            saveResult = -1;
        }else{
            Student queryStudentResult = studentDao.queryStudentByPhone(student.getPhone());
            if(queryStudentResult != null){
                saveResult = 2;
            }else{
                //该学生尚未存在，保存到数据库中
                saveResult = studentDao.saveStudent(student);
            }
        }
        return saveResult;
    }

    @Override
    public Student queryStudent(Integer id) {
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(new Jackson2JsonRedisSerializer(Student.class));
        final String STUDENT_USER_KEY = "STUDENT:";
        String key = STUDENT_USER_KEY + id;
        //先尝试从缓存获取:按照key的格式来查
        Student student = (Student) redisTemplate.opsForValue().get(key);
        System.out.println("------- 从redis中查询数据 ----------> : " + student);
        if(student == null){
            //缓存中没有,需要到数据库查询：按照id格式来查询
            student = studentDao.queryStudentById(id);
            System.out.println("------- 从数据库中查询数据 ---------> : " + student);
            if(student != null){
                //数据库中有该数据,存一份数据到redis中：按照key的格式来存
                redisTemplate.opsForValue().set(key, student);
            }else{
                //防止缓存穿透：对既未在缓存又未在数据库中的数据，设置默认值
                redisTemplate.opsForValue().set(key, Student.getDefaultStudent());
            }
        }
        return student;
    }
}

• springboot主启动类上添加支持dubbo的注解并添加对dao接口扫描的注解

package com.example;

import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@EnableDubbo
@MapperScan(basePackages = "com.example.demo.dao")
public class StudentserviceProviderApplication {

    public static void main(String[] args) {
        SpringApplication.run(StudentserviceProviderApplication.class, args);
    }
}

dubbo消费者项目

该项目为springboot项目，启动项依赖只要勾选web依赖

pom.xml中的额外依赖均与服务提供者相同

项目配置

• 配置application.properties

#springboot服务的基本配置
server.port=9090
server.servlet.context-path=/demo

#springboot中使用dubbo的配置
#消费者名称
dubbo.application.name=student-service-consumer

#配置需要扫描的包
dubbo.scan.base-packages=com.example.demo.controller

#配置注册中心
dubbo.registry.address=zookeeper://127.0.0.1:2181

• 同样在springboot的启动类上添加支持dubbo的注解

package com.example;

import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@EnableDubbo
public class StudentConsumerApplication {

    public static void main(String[] args) {
        SpringApplication.run(StudentConsumerApplication.class, args);
    }
}

controller层

• 消费者与前端交互的controller层, 采用RESTful接口风格

package com.example.demo.controller;

import com.example.demo.model.Student;
import com.example.demo.service.StudentService;
import org.apache.dubbo.config.annotation.DubboReference;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class StudentController {

    @DubboReference(interfaceClass = StudentService.class, version = "1.0.0")
    private StudentService studentService;

    @PostMapping("/student/add")
    public String addStudent(Student student){
        int saveStudentResult = studentService.saveStudent(student);
        String msg = "";
        if(saveStudentResult == 1){
            msg = "添加学生: " + student.getName() + " 成功";
        }else if(saveStudentResult == -1){
            msg = "手机号不能为空";
        }else if(saveStudentResult == 2){
            msg = "手机号: " + student.getPhone() + " 重复，请更换手机号后重试";
        }
        return msg;
    }

    @PostMapping("/student/query")
    public String queryStudent(Integer id){
        String msg = "";
        Student student = null;
        if(id != null && id > 0){
            student = studentService.queryStudent(id);
            if(student != null){
                msg = "查询到的学生信息: " + student.toString();
            }else{
                msg = "未查询到相关信息";
            }
        }else{
            msg = "输入的id范围不正确";
        }
        return msg;
    }
}

前端页面

前端html页面和js文件位于resources/static目录下

• 可以借助postman便捷的发送post请求来添加学生

• 查询学生的请求可以借助如下query.html页面，通过ajax来发送查询请求

html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>query.htmltitle>
    <script src="../js/jquery-1.11.1-min.js">script>
    <script type="text/javascript">
        $(function (){
            $("#stuBtn").click(function (){
                var id = $("#stuId").val();
                $.ajax({
                    url: "/demo/student/query",
                    data:{"id":id},
                    type:"post",
                    dataType:"text",
                    success:function (data){
                        alert(data);
                    }
                })
            });
        });
    script>
head>
<body>
<input type="text" id="stuId"><br>
<input type="button" id="stuBtn" value="查询">
body>
html>