Springboot+MyBatis+Redis极简restful风格后台搭建

前置知识：JavaWeb、Mysql、Springboot等入门知识

一、配置环境

1.mysql环境

此部分请跳到：
https://blog.csdn.net/bobo553443/article/details/81383194

2.Redis环境

此部分请跳到：https://blog.csdn.net/GDUT_xin/article/details/108986323

二、项目搭建

1.创建项目

创建一个普通的 Springboot 项目

此部分请跳到：
https://blog.csdn.net/qq_34491508/article/details/91369794

2.配置依赖

spring-boot-starter-web包中含有spring-boot-starter，要将spring-boot-starter去掉，以免包冲突！

       
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>
 
        <dependency>
            <groupId>org.mybatis.spring.bootgroupId>
            <artifactId>mybatis-spring-boot-starterartifactId>
            <version>2.1.3version>
        dependency>
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
        dependency>
        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-data-redisartifactId>
        dependency>

3.主配置文件

根据自身情况配置！

#restful端口
server.port=8080
#数据源
spring.datasource.driver-class-name = com.mysql.cj.jdbc.Driver
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.url = jdbc:mysql://localhost:3306/*?serverTimezone=UTC
#redis
spring.redis.host=localhost
spring.redis.port=6379
#缓存
spring.cache.type=redis
spring.cache.cache-names=redisCache

4. Redis配置类

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import java.net.UnknownHostException;
/**
 * 自定义序列化，防止乱码
 */
@Configuration
@EnableCaching
public class RedisConfig {

	@Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory)
            throws UnknownHostException {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        //String的序列化器
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        template.setKeySerializer(stringRedisSerializer);
        template.setHashKeySerializer(stringRedisSerializer);
      	template.setValueSerializer(stringRedisSerializer);
        template.setHashValueSerializer(stringRedisSerializer);
        return template;
    }
}

5.允许跨域

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
/**
 * 允许跨域
 */
@Configuration
public class CrossConfig implements WebMvcConfigurer {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("*")
                .allowedMethods("GET","HEAD","POST","PUT","DELETE","OPTIONS")
                .allowCredentials(true)
                .maxAge(3600)
                .allowedHeaders("*");
    }
}

6.POJO类

要在数据库中添加对应的表以供测试！

import org.springframework.stereotype.Component;
import org.springframework.validation.annotation.Validated;
import java.io.Serializable;

@Component
public class User implements Serializable {

    private Integer id;
	private String password;

    public Integer getId() {
        return id;
    }

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

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                '}';
    }

    public User() {
    }
}

7.Dao层

@Mapper//sql映射类
public interface UserDao {

	/*
		mybatis的sql映射方法
		@Param是给参数给定义一个参数名			
		#{}是springEL，根据参数名取值
	*/
	    @Select("select * from user where id = #{id} and password = #{password}")
	User getUserByIdAndPassword(@Param("id") int id, @Param("password") String password);

	    @Select("select * from user where id = #{id}")
    User getUserById(@Param("id")int id);
   
}

8.Service层

接口

import com.xmvp.pojo.User;
import java.util.List;

public interface UserService {
   
    User login(int id, String password);

    User getUserById(int id);
    
}

实现类

import com.xmvp.dao.UserDao;
import com.xmvp.pojo.User;
import com.xmvp.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {


    private final UserDao userDao;

    public UserServiceImpl(UserDao userDao) {
        this.userDao = userDao;
    }


    @Override
    public User login(int id, String password) {
        return userDao.getUserByIdAndPassword(id,password);
    }

    @Override
    public User getUserById(int id) {
        return userDao.getUserById(id);
    }

}

9.Controller层

import com.xmvp.pojo.User;
import com.xmvp.service.UserService;
import org.springframework.cache.annotation.CachePut;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

/**
 * @RestController 默认包含以下注解
 * @Controller 控制层组件
 * @ResponseBody 直接返回给页面JSON
 */
@RestController
public class UserController {

    private final UserService userService;

    public UserController(UserService userService) {
        this.userService = userService;
    }

    /*
    	restful风格，按资源路径规范取资源
    	{}是接受相应位置的值来赋值
    	@PathVariable 是将{}中的同名变量拿来作方法的输入值
    	因为输入相同id和密码的概率小，无需缓存
    */
    @RequestMapping(value ="/user/{id}/{password}",method = RequestMethod.GET)
    public User login(@PathVariable int id,@PathVariable String password){
        User user = userService.login(id,password);
        return user;
    }

    /**
     * 查询某个id的次数可能会很多，@Cacheable 加入缓存机制
     * #result可以取得方法的返回值，#id取得参数id的值，value是redis的key的前缀
     * condition如果表达式结果为true则会执行缓存的相关操作
     */
    @RequestMapping(value = "/user/id/{id}",method = RequestMethod.GET)
    @CachePut(value = "redisCache",condition = "#result != 'null'",key = "'user_'+#id")
    public User getUserById(@PathVariable int id){
        return userService.getUserById(id);
    }
}

10.启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

@SpringBootApplication
/**
 * 允许缓存（这里用redis）
 */
@EnableCaching
public class SpringbootDemoApplication {

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

}

三、运行测试

1.接口调用

启动 main 方法后，开启浏览器，根据 Controller 层中@RequestMapping注解中的restful风格的资源路径规范输入！

输入示例：

查询：localhost:8080/user/id/10000
登录：localhost:8080/user/10000/10000

得到JSON字符串即为搭建后台成功！把接口交给前端程序员就可以了！

2.测试类

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;

@SpringBootTest
public class RedisTest {
    
    @Autowired
    /*
        指定别名
        会使用我们RedisConfig定义的RedisTemplate类
     */
    @Qualifier(value = "redisTemplate")
    private RedisTemplate redisTemplate;
    
    @Test
    void test(){
        /*
            还记得@Cacheable(value = "redisCache",condition = "#result != 'null'",key = "'user_'+#id")吗？
            key是  [redis库名]::[key]
         */
        System.out.println(redisTemplate.opsForValue().get("redisCache::user_10000"));
    }
}

运行得到的是String序列化后的结果

3.观测redis后台：

后台 redis-cli 输入与输出示例：

127.0.0.1:6379> keys *
1) "redisCache::user_10000"
127.0.0.1:6379> get redisCache::user_10000
"\xac\xed\x00\x05sr\x00\x12com.xmvp.pojo.User\x1dL\xfa\xd9\xdd\xb58m\x02\x00\x04L\x00\x05emailt\x00\x12Ljava/lang/String;L\x00\x02idt\x00\x13Ljava/lang/Integer;L\x00\x04nameq\x00~\x00\x01L\x00\bpasswordq\x00~\x00\x01xpt\x00\[email protected]\x00\x11java.lang.Integer\x12\xe2\xa0\xa4\xf7\x81\x878\x02\x00\x01I\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00'\x10t\x00\x05admint\x00\x0510000"

可以看到对象以String方式存储着

127.0.0.1:6379> info
#...
# Clients
connected_clients:2
client_recent_max_input_buffer:2
client_recent_max_output_buffer:0
blocked_clients:0

可以看到有两个连接，一个是目前的控制台，一个是Springboot。