SpringBoot入门练习

古城微笑少年丶 2022-12-08 04:16 168阅读 0赞

#### 一、创建项目出现的问题 ####

问题1、application.yml文件无法识别
    	*解决方法：File->Settions->Plugins目录下
    	选中YAML，重启IDEA
    问题2、application.yml文件图标错误
    	*解决方法：File->Settings->File Types下
    	删除*.yml

#### 二、创建一个SpringBoot的项目 ####

1.  New Project
2.  选择Spring Initializr
3.  选择Web下的Web，然后Flish
4.  导入依赖

<parent>
     	<groupId>org.springframework.boot</groupId>
     	<artifactId>spring-boot-starter-parent</artifactId>
     	<version>2.1.5.RELEASE</version>
     </parent>
    
     <dependencies>
     	
     	<dependency>
     		<groupId>org.springframework.boot</groupId>
     		<artifactId>spring-boot-starter-web</artifactId>
     	</dependency>
     	
     	<dependency>
     		<groupId>org.springframework.boot</groupId>
     		<artifactId>spring-boot-devtools</artifactId>
     	</dependency>
     </dependencies>

**IDEA设置，完成热部署**

在Settings中找到Compiler，选中Build Project automatically  
按Ctrl+Shift+Alt+/:选中compiler.automake.allow.when.app.running

底层分析：

spring-boot-starter-parent：springboot起步依赖
    	在spring-boot-starter-parent中
    	resources资源引入：
    		${basedir}/src/main/resources下的
    			application*.yml
    			application*.yaml
    			application*.properties文件
    	在spring-boot-dependencies中
    		自动根据spring-boot-starter-parent的版本匹配相应的版本，进行了版本控制的作用
    	自动配置分析：
    	@SpringBootApplication
    		标志该类是一个配置类：@Configration

#### 三、SpringBoot整合Mybatis ####

第1步：导依赖：

<dependency>
    	<groupId>org.mybatis.spring.boot</groupId>
    	<artifactId>mybatis-spring-boot-starter</artifactId>
    	<version>2.0.1</version>
    </dependency>
    
    
    <dependency>
    	<groupId>mysql</groupId>
    	<artifactId>mysql-connector-java</artifactId>
    	<version>5.1.6</version>
    </dependency>

第2步：yml配置文件  
\#数据库配置spring:  
\#配置Mybatis配置信息  
\#spring集成Mybatis环境  
\#pojo别名扫描包

spring:
    datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 123456
    
    mybatis:
    	type-aliases-package: com.zero.domain
    	mapper-locations: classpath:mapper/*Mapper.xml

第3步：创建实体

package com.zero.domain;
    
    public class User {
    	private Integer id;
    	private String name;
    	private String pass;
    
    	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 getPass() {
        	return pass;
    	}
    
    	public void setPass(String pass) {
        	this.pass = pass;
    	}
    
    	@Override
    	public String toString() {
        	return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pass='" + pass + '\'' +
                '}';
    		}
    	}

第4步：创建接口

package com.zero.mapper;
    
    import com.zero.domain.User;
    import org.apache.ibatis.annotations.Mapper;
    
    import java.util.List;
    
    @Mapper
    public interface UserMapper {
    
    	public List<User> queryUserList();
    
    }

第5步：创建映射文件

<?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.zero.mapper.UserMapper">
    	<select id="queryUserList" resultType="user">
        	SELECT * FROM demo
    	</select>
    </mapper>

第6步：测试

package com.zero.controller;
    
    import com.zero.domain.User;
    import com.zero.mapper.UserMapper;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.List;
    
    //以json格式或字符串格式回写
    @RestController
    public class democontroller {
    
    	@Autowired
    	private UserMapper userMapper;
    
    	@RequestMapping("/quick")
    	public List<User> queryUserList(){
        	List<User> users = userMapper.queryUserList();
    
        	return users;
    
    	}
    }

#### 四、SpringBoot整合Spring Data JPA ####

第1步：导入依赖

<dependency>
    	<groupId>org.springframework.boot</groupId>
    	<artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    
    <dependency>
    	<groupId>mysql</groupId>
    	<artifactId>mysql-connector-java</artifactId>
    	<version>5.1.6</version>
    </dependency>
    
    <dependency>
    	<groupId>javax.xml.bind</groupId>
    	<artifactId>jaxb-api</artifactId>
    	<version>2.3.0</version>
    </dependency>

第2步：创建实体，使用注解进行配置

package com.zero.domain;
    
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    
    @Entity
    public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String name;
    private String pass;
    
    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 getPass() {
        return pass;
    }
    
    public void setPass(String pass) {
        this.pass = pass;
    }
    
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pass='" + pass + '\'' +
                '}';
    }
    }

第3步：创建接口

package com.zero.reposytory;
    
    import com.zero.domain.User;
    import org.springframework.data.jpa.repository.JpaRepository;
    import java.util.List;
    
    public interface UserReposytory extends JpaRepository<User,Integer> {
    
    	public List<User> findAll();
    
    }

第4步：创建yml配置

spring:
    	datasource:
    		driver-class-name: com.mysql.jdbc.Driver
    		url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    		username: root
    		password: 123456
    #JPA Configuration
    	jpa:
    		database: MySQL
    		show-sql: true
    		generate-ddl: true
    		hibernate:
      			ddl-auto: update

第5步：测试

package com.zero;
    
    import com.zero.domain.User;
    import com.zero.reposytory.UserReposytory;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.test.context.junit4.SpringRunner;
    import java.util.List;
    
    
    @RunWith(SpringRunner.class)
    @SpringBootTest(classes = Demo614Application.class)
    public class JpaTest {
    	@Autowired
    	private UserReposytory userReposytory;
    
    	@Test
    	public void test(){
        	List<User> all = userReposytory.findAll();
        	System.out.println(all);
    	}
    }

#### 五、Redis缓存 ####

第1步：配置yml文件信息

#redis
    redis:
    	host: 127.0.0.1
    	port: 6379

第2步：测试

package com.zero;
    
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.zero.domain.User;
    import com.zero.reposytory.UserReposytory;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.data.redis.core.RedisTemplate;
    import org.springframework.test.context.junit4.SpringRunner;
    
    import java.util.List;
    
    @RunWith(SpringRunner.class)
    @SpringBootTest(classes = Demo614Application.class)
    public class RedisTest {
    
    	@Autowired
    	private RedisTemplate<String,String> redisTemplate;
    
    	@Autowired
    	private UserReposytory userReposytory;
    
    	@Test
    	public void test() throws JsonProcessingException {
        	//1.从Redis中获取数据,json字符串
        	String s = redisTemplate.boundValueOps("user.findall").get();
        	//2.判断Redis中是否存在想要的数据
        	if(null==s){
            	//3.1:不存在，从数据库中查询
            	List<User> all = userReposytory.findAll();
            	//3.2:将查询出的数据存储到Redis中
            	//通过web先将集合换换成json的字符串，使用Jackson进行转换
            	ObjectMapper ob = new ObjectMapper();
            	s = ob.writeValueAsString(all);
            	redisTemplate.boundValueOps("user.findall").set(s);
            	System.out.println("从数据库中获取数据");
        	}else {
            	System.out.println("从Redis缓存中获取数据");
        	}
    
        	//4.将数据打印在控制台
        	System.out.println(s);
    	}
    }