一：示例描述

Springboot+mp+redis

// 学生表  id sname cid   

//班级表  cid cname

缓存注解一般是在service层

1.查询所有的班级  以及班级中的所有的信息 并能缓存 到rdis里面

（不要求分页）

2.Stream流 获取第二页的数据 （ 每页数据有2条）

二：实现

pom.xml依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.12.4</version>
        </dependency>

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.3</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.5.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.velocity</groupId>
            <artifactId>velocity-engine-core</artifactId>
            <version>2.3</version>
        </dependency>

        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
        </dependency>


        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>


        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.6</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>


        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.15</version>
        </dependency>

application.properties

spring.redis.host=192.168.247.36
spring.redis.port=6379
spring.redis.password=chn
spring.redis.database=0



spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql:///od?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=root
#  ??? ??  ????java?util.Date ???????
spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
spring.jackson.time-zone=GMT+8
spring.jackson.serialization.write-date-keys-as-timestamps=false
#logging.level.com.baomidou.ant.test.dao=debug
#mybatis-plus tab_hjhj
mybatis-plus.configuration.map-underscore-to-camel-case=true
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
#mybatis-plus.configuration.log-impl=
mybatis-plus.mapper-locations=classpath:/mapper/*.xml
#????   ???????0  ???1
mybatis-plus.global-config.db-config.logic-not-delete-value=0
mybatis-plus.global-config.db-config.logic-delete-value=1

mybatis-plus自动生成代码类

( entity,service,controller,mapper,controller层代码)

package com.aaa;

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.generator.FastAutoGenerator;
import com.baomidou.mybatisplus.generator.config.OutputFile;
import com.baomidou.mybatisplus.generator.fill.Column;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class MyTest {
    public static void main(String[] args) {
        FastAutoGenerator.create("jdbc:mysql://localhost:3306/od","root","root")
                // 全局配置
                .globalConfig((scanner, builder) -> builder
                        .author("作者名字")
                        .outputDir("E:\\IDEA\\object\\springbootRedis03\\src\\main\\java")
                )
                // 包配置
                .packageConfig(
                        (scanner, builder) ->
                                builder
                                        .parent("com.aaa")
                                        .pathInfo(Collections.singletonMap(OutputFile.xml, "E:\\IDEA\\object\\springbootRedis03\\src\\main\\resources\\mapper")))
                // 策略配置
                .strategyConfig((scanner, builder) -> builder.addInclude(getTables(scanner.apply("请输入表名，多个英文逗号分隔？所有输入 all")))
                        .controllerBuilder().enableRestStyle().enableHyphenStyle()
                        .entityBuilder().enableLombok().addTableFills(
                                new Column("create_time", FieldFill.INSERT)
                        ).build())
                /*
                    模板引擎配置，默认 Velocity 可选模板引擎 Beetl 或 Freemarker
                   .templateEngine(new BeetlTemplateEngine())
                   .templateEngine(new FreemarkerTemplateEngine())
                 */
                .execute();


// 处理 all 情况

    }

    protected static List<String> getTables(String tables) {
        return "all".equals(tables) ? Collections.emptyList() : Arrays.asList(tables.split(","));
    }
}

具体数据库根据实际情况手动选择（我这里是od数据库下 classs表和student表）

redisConfig 序列化处理，缓存

package com.aaa.config;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.cache.CacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
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.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import java.time.Duration;

@Configuration
public class RedisConfig {

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        RedisSerializer<String> redisSerializer = new StringRedisSerializer();
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper om = new ObjectMapper();
        // 指定要序列化的域，field,get和set,以及修饰符范围，ANY是都有包括private和public
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        // 指定序列化输入的类型，类必须是非final修饰的，final修饰的类，比如String,Integer等会跑出异常
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        template.setConnectionFactory(factory);
        //key序列化方式
        template.setKeySerializer(redisSerializer);
        //value序列化
        template.setValueSerializer(jackson2JsonRedisSerializer);
        //value hashmap序列化
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        return template;
    }

    /**
     * 缓存处理
     *
     * @param factory
     * @return
     */
    @Bean
    public CacheManager cacheManager(RedisConnectionFactory factory) {
        RedisSerializer<String> redisSerializer = new StringRedisSerializer();
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
    //解决查询缓存转换异常的问题
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
    // 配置序列化（解决乱码的问题）,过期时间600秒
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofSeconds(600))
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
                .disableCachingNullValues();
        RedisCacheManager cacheManager = RedisCacheManager.builder(factory)
                .cacheDefaults(config)
                .build();
        return cacheManager;
    }


}

@SpringBootApplication
@EnableCaching #开启缓存
public class SpringbootRedis03Application {

public static void main(String[] args) {
SpringApplication.run(SpringbootRedis03Application.class, args);
}

}

entity层

@Data
public class Classs implements Serializable {

    private static final long serialVersionUID = 1L;

    @TableId(value = "cid", type = IdType.AUTO)
    private Integer cid;

    private String cname;

    @TableField(exist = false)
    private List<Student> studentList;

}

@Data
public class Student implements Serializable {

    private static final long serialVersionUID = 1L;

    @TableId(value = "sid", type = IdType.AUTO)
    private Integer sid;

    private String sname;

    private Integer cid;

}

service层

IClasssService.java

public interface IClasssService extends IService<Classs> {



//    @CachePut(value = "aClass",key = "#classs.cid")
    public boolean add(Classs classs);

    @CachePut(value = "dClass",key = "#cid")
    boolean delete(Integer cid);

    @CacheEvict(value = "gClass",key="#root.targetClass")
    boolean update(Classs classs);


    @Cacheable(value = "gClass")
    public List<Classs> getAll();

    @Cacheable(value = "oClass")
    public List<Classs> gets(Integer pageNumber,Integer pageSize);


}

impl

@Service
public class ClasssServiceImpl extends ServiceImpl<ClasssMapper, Classs> implements IClasssService {
    @Autowired
    private RedisTemplate redisTemplate;
    @Autowired
    private ClasssMapper cm;

    @Override
    @Cacheable(value = "gClass")
    public List<Classs> getAll() {
        return cm.getAllc();
    }

    @Override
    public boolean add(Classs classs) {
        return this.save(classs);
    }

    @Override
    public boolean delete(Integer cid) {
        return this.removeById(cid);
    }

    @Override
    public boolean update(Classs classs) {
        return this.updateById(classs);
    }

    @Override
    public List<Classs> gets(Integer pageNumber,Integer pageSize) {
        List<Classs> allc = this.getAll();
        List<Classs> resultList = allc.stream()
                .skip((pageNumber - 1) * pageSize) // 跳过前面的记录数
                .limit(pageSize) // 获取指定数量的记录
                .collect(Collectors.toList()); // 将结果收集到新的 List 中
        return resultList;
    }
}

mapper层

注解形式

@Mapper
public interface ClasssMapper extends BaseMapper<Classs> {

    @Select("select * from Classs")
    @Results({
            @Result(id = true, property = "cid", column = "cid"),
            @Result(property = "studentList", column = "cid",
                    javaType = List.class,
                    many = @Many(select = "com.aaa.mapper.StudentMapper.getStudentByCid"))
    })
    List<Classs> getAllc();
}

xml形式

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.aaa.mapper.ClasssMapper">

<resultMap id="lls" type="com.aaa.entity.Classs" autoMapping="true">
    <id property="cid" column="cid"></id>
    <collection property="studentList" ofType="com.aaa.entity.Student" autoMapping="true">
        <id property="cid" column="cid"></id>
    </collection>
</resultMap>
    <select id="cid" resultMap="lls">
        select * from classs,student where classs.cid=student.cid
    </select>
</mapper>

controller层

@RestController
@RequestMapping("/classs")
public class ClasssController {

    @Autowired
    private IClasssService iClasssService;


    @PostMapping
    public String add(@RequestBody Classs classs) {
        boolean b = iClasssService.add(classs);
        System.out.println(classs);
        if (b) {
            return "ok";
        }
        return "default";
    }


    @DeleteMapping("{cid}")
    public String delete(@PathVariable Integer cid) {
        boolean b = iClasssService.delete(cid);
        if (b){
            return "ok";
        }
        return "default";
    }


    @PutMapping
    public String update(@RequestBody Classs classs){
        boolean b = iClasssService.update(classs);
        if (b){
            return "ok";
        }
        return "default";
    }



    @GetMapping
    public List<Classs> get() {

        return iClasssService.getAll();
    }




    @GetMapping("{pageNumber}/{pageSize}")
    public List<Classs> gets(@PathVariable Integer pageNumber,@PathVariable Integer pageSize) {
        List<Classs> list = iClasssService.gets(pageNumber, pageSize);
        return list;
    }

}

测试