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SpringBoot与Spring中数据缓存Cache超详细讲解

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目录 一、Spring缓存支持 1、@Cacheable 2、@CacheEvict 3、@CachePut 4、Caching 5、CacheConfig 二、Spring Boot缓存支持 一、Spring缓存支持 Spring框架定义了org.springframework.cache CacheManager和org.springframewor
目录
  • 一、Spring缓存支持
    • 1、@Cacheable
    • 2、@CacheEvict
    • 3、@CachePut
    • 4、Caching
    • 5、CacheConfig
  • 二、Spring Boot缓存支持

    一、Spring缓存支持

    Spring框架定义了org.springframework.cache CacheManager和org.springframework.cache.Cache接口来统一不同的缓存技术

    CacheManager常用方法如下

    1、@Cacheable

    该注解可以标记在一个方法上,也可以标记在一个类上,当标记在一个方法上时表示该方法是支持缓存的,当标记在一个类上时则表示该类所有的方法都是支持缓存的。对于一个支持缓存的方法,在方法执行前,Spring先检查缓存中是否存在方法返回的数据,如果存在则直接返回缓存数据,如果不存在,则调用方法并将方法返回值存入缓存

    2、@CacheEvict

    该注解用来标注在需要清楚缓存元素的方法或类上,当标记在一个类上时,表示其中所有方法的执行都会触发缓存的清除操作

    3、@CachePut

    该注解也可以声明一个方法支持缓存功能

    4、Caching

    该注解可以在一个方法或类上同时指定多个Spring Cache相关的注解

    5、CacheConfig

    该注解作用在类上可以设置当前缓存的一些公共设置

    二、Spring Boot缓存支持

    1:创建基于spring-voot-starter-cache 和spring-boot-starter-data-jpa依赖的Spring BootWeb应用

    2:配置application.properties文件 代码如下

    server.servlet.context-path=/ch6_10
    ###
    ##数据源信息配置
    ###
    #数据库地址
    spring.datasource.url=jdbc:mysql://localhost:3306/springbootjpa?characterEncoding=utf8
    #数据库用户名
    spring.datasource.username=root
    #数据库密码
    spring.datasource.password=root
    #数据库驱动
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver
    ####
    #JPA持久化配置
    ####
    #指定数据库类型
    spring.jpa.database=MYSQL
    #指定是否在日志中显示SQL语句
    spring.jpa.show-sql=true
    #指定自动创建、更新数据库表等配置,update表示如果数据库中存在持久化类对应的表就不创建,不存在就创建对应的表
    spring.jpa.hibernate.ddl-auto=update
    #让控制器输出的JSON字符串格式更美观
    spring.jackson.serialization.indent-output=true 

    3:修改pom.xml文件 添加mysql依赖

    <?xml version="1.0" encoding="UTF-8"?>
    -<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0">
    <modelVersion>4.0.0</modelVersion>
    -<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.8.RELEASE</version>
    <relativePath/>
    <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ch</groupId>
    <artifactId>ch6_10</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ch6_10</name>
    <description>Demo project for Spring Boot</description>
    -<properties>
    <java.version>11</java.version>
    </properties>
    -<dependencies>
    -<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
    </dependency>
    -<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    -<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- 添加MySQL依赖 -->
    -<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.45</version>
    <!-- MySQL8.x时,请使用8.x的连接器 -->
    </dependency>
    -<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
    </dependency>
    </dependencies>
    -<build>
    -<plugins>
    -<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    </plugin>
    </plugins>
    </build>
    </project>

    4:创建持久化实体类

    代码如下

    package com.ch.ch6_10.entity;
    import java.io.Serializable;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.Table;
    import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
    @Entity
    @Table(name = "student_table")
    @JsonIgnoreProperties(value = {"hibernateLazyInitializer"})
    public class Student implements Serializable{
    	private static final long serialVersionUID = 1L;
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	private int id;//主键
    	private String sno;
    	private String sname;
    	private String ssex;
    	public Student() {
    		super();
    	}
    	public Student(int id, String sno, String sname, String ssex) {
    		super();
    		this.id = id;
    		this.sno = sno;
    		this.sname = sname;
    		this.ssex = ssex;
    	}
    	public int getId() {
    		return id;
    	}
    	public void setId(int id) {
    		this.id = id;
    	}
    	public String getSno() {
    		return sno;
    	}
    	public void setSno(String sno) {
    		this.sno = sno;
    	}
    	public String getSname() {
    		return sname;
    	}
    	public void setSname(String sname) {
    		this.sname = sname;
    	}
    	public String getSsex() {
    		return ssex;
    	}
    	public void setSsex(String ssex) {
    		this.ssex = ssex;
    	}  
    }

    5:创建数据访问接口

    package com.ch.ch6_10.repository;
    import org.springframework.data.jpa.repository.JpaRepository;
    import com.ch.ch6_10.entity.Student;
    public interface StudentRepository extends JpaRepository<Student, Integer>{
    }

    6:创建业务层 包括一个接口和一个实现类

    接口代码如下

    package com.ch.ch6_10.service;
    import com.ch.ch6_10.entity.Student;
    public interface StudentService {
    	public Student saveStudent(Student student);
    	public void deleteCache(Student student);
    	public Student selectOneStudent(Integer id);
    }

    实现类代码如下

    package com.ch.ch6_10.service;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.cache.annotation.CacheEvict;
    import org.springframework.cache.annotation.CachePut;
    import org.springframework.cache.annotation.Cacheable;
    import org.springframework.stereotype.Service;
    import com.ch.ch6_10.entity.Student;
    import com.ch.ch6_10.repository.StudentRepository;
    @Service
    public class StudentServiceImpl implements StudentService{
    	@Autowired
    	private StudentRepository studentRepository;
    	@Override
    	@CachePut(value = "student", key="#student.id")
    	public Student saveStudent(Student student) {
    		Student s = studentRepository.save(student);
    		System.out.println("为key=" + student.getId() + "数据做了缓存");
    		return s;
    	}
    	@Override
    	@CacheEvict(value = "student", key="#student.id")
    	public void deleteCache(Student student) {
    		System.out.println("删除了key=" + student.getId() + "的数据缓存");
    	}
    	@Override
    	@Cacheable(value = "student")
    	public Student selectOneStudent(Integer id) {
    		Student s = studentRepository.getOne(id);
    		System.out.println("为key=" + id + "数据做了缓存");
    		return s;
    	}
    }

    7:创建控制器层

    package com.ch.ch6_10.controller;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import com.ch.ch6_10.entity.Student;
    import com.ch.ch6_10.service.StudentService;
    @RestController
    public class TestCacheController {
    	@Autowired
    	private StudentService studentService;
    	@RequestMapping("/savePut")
    	public Student save(Student student) {
    		return studentService.saveStudent(student);
    	}
    	@RequestMapping("/selectAble")
    	public Student select(Integer id) {
    		return studentService.selectOneStudent(id);
    	}
    	@RequestMapping("/deleteEvict")
    	public String deleteCache(Student student) {
    		studentService.deleteCache(student);
    		return "ok";
    	}
    }

    8:在主类中开启缓存支持

    package com.ch.ch6_10;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cache.annotation.EnableCaching;
    @EnableCaching
    @SpringBootApplication
    public class Ch610Application {
    	public static void main(String[] args) {
    		SpringApplication.run(Ch610Application.class, args);
    	}
    }

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