目录
- 1.什么是springboot自动装配?
- 2.springboot注解:
- 3.springboot整合myBATisplus实现增删改查
1.什么是springboot自动装配?
自动装配是springboot的核心,一般提到自动装配就会和springboot联系在一起。实际上 Spring Framework 早就实现了这个功能。Spring Boot 只是在其基础上,通过 SPI 的方式,做了进一步优化。
SpringBoot 定义了一javascript套接口规范,这套规范规定:SpringBoot 在启动时会扫描外部引用 jar 包中的META-INF/spring.factories文件,将文件中配置的类型信息加载到 Spring 容器(此处涉及到 JVM 类加载机制与 Spring 的容器知识),并执行类中定义的各种操作。对于外部 jar 来说,只需要按照 SpringBoot 定义的标准,就能将自己的功能装置进 SpringBoot
2.springboot注解:
@EnableAutoConfiguration:扫包范围默认当前类。
@ComponentScan(" “) 扫包范围默认当前类所在的整个包下面所有类。扫包范围大于@EnableAutoConfiguration,@ComponentScan(” ")依赖于@EnableAutoConfiguration启动程序。@EnableAutoConfiguration@ComponentScan("第三方包 ")app.run()@SpringBootApplication 扫包范围同级包和当前包。@SpringBootApplication 底层等同于@EnableAutoConfiguration+@ComponentScan。不扫描第三方包3.springboot整合mybatisplus实现增删改查
1.首先导入相关依赖
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.5.1</version> </dependency> <dependency> <groupId>com.spring4all</groupId> <artifactId>swagger-spring-boot-starter</artifactId> <version>1.9.1.RELEASE</version> </dependency> <dependency> <groupId>com.github.xiaoymin</groupId> <artifactId>swagger-bootstrap-ui</artifactId> <version>1.7.8</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-Java</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> </dependencies>
2.创建数据表并添加数据
DROP TABLE IF EXISTS `category`; CREATE TABLE `category` ( `cid` varchar(32) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NOT NULL, `cname` varchar(50) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NULL DEFAULT NULL, PRIMARY KEY (`cid`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8mb3 COLLATE = utf8mb3_general_ci ROW_FORMAT = DYNAMIC; -- ---------------------------- -- Records of category -- ---------------------------- INSERT INTO `category` VALUES ('c001', '家电'); INSERT INTO `category` VALUES ('c002', '鞋服'); INSERT INTO `category` VALUES ('c003', '化妆品'); INSERT INTO `ca开发者_Js入门tegory` VALUES ('c004', '汽车'); -- ---------------------------- -- Table structure for products -- ---------------------------- DROP TABLE IF EXISTS `products`; CREATE TABLE `products` ( `pid` varchar(32) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NOT NULL, `pname` varchar(50) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NULL DEFAULT NULL, `price` int NULL DEFAULT NULL, `flag` varchar(2) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NULL DEFAULT NULL, `category_id` varchar(32) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NULL DEFAULT NULL, PRIMARY KEY (`pid`) USING BTREE, INDEX `category_id`(`category_id`) USING BTREE, CONSTRAINT `products_ibfk_1` FOREIGN KEY (`category_id`) REFERENCES `category` (`cid`) ON DELETE RESTRICT ON UPDATE RESTRICT ) ENGINE = InnoDB CHARACTER SET = utf8mb3 COLLATE = utf8mb3_general_ci ROW_FORMAT = DYNAMIC; -- ---------------------------- -- Records of products -- ---------------------------- INSERT INTO `products` VALUES ('p001', '小\r\n米电视 机', 5000, '1', 'c001'); INSERT INTO `products` VALUES ('p002', '格\r\n力空调', 3000, '1', 'c001'); INSERT INTO `products` VALUES ('p003', '美\r\n的冰箱', 4500, '1', 'c001'); INSERT INTO `products` VALUES ('p004', '篮\r\n球鞋', 800, '1', 'c002'); INSERT INTO `products` VALUES ('p005', '运\r\n动裤', 200, '1', 'c002'); INSERT INTO `products` VALUES ('p006', 'T\r\n恤', 300, '1', 'c002'); INSERT INTO `products` VALUES ('p009', '篮球', 188, '1', 'c002');
3.在项目中创建如下目录
4.在resources下创建application.propertis并配置数据源
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver spring.datasource.username=root spring.datasource.password=123456 spring.datasource.url=jdbc:mysql:///springboot #日志 mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl mybatis.mapper-locations=classpath:mapper/*.XML
5.在pojo下创建实体类
package com.azy.pojo; import java.io.Serializable; import com.baomidou.mybatisplus.annotation.IdType; import com.baomidou.mybatisplus.annotation.TableField; import com.baomidou.mybatisplus.annotation.TableId; import com.baomidou.mybatisplus.annotation.TableName; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; /** * products * @author */ @Data @AllArgsConstructor @NoArgsConstructor @TableName(value = "products") public cpythonlass Products implements Serializable { @TableId(type = IdType.AUTO) private String pid; public Products(String pid, String pname, Integer price) { this.pid = pid; this.pname = pname; this.price = price; } private String pname; private Integer price; private String flag; private String category_id; @TableField(exist = false) private Category category; private static final long serialVersionUID = 1L; }
6.在dao层下创建ProductDao这个接口,由于mybatisplus封装了单表的增删改查,所有只需继承BaseMapper这个接口就ok
package com.azy.dao; import com.azy.pojo.Products; import com.baomidou.mybatisplus.core.conditions.Wrapper; import com.baomidou.mybatisplus.core.mapper.BaseMapper; import com.baomidou.mybatisplus.core.metadata.IPage; import org.apache.ibatis.annotations.Param; /** * @ fileName:ProductsDao * @ description: * @ author:Azy * @ createTime:2023/4/11 18:57 * @ version:1.0.0 */ public interface ProductsDao extends BaseMapper<Products> { IPage<Products> findPage(IPage<Products> iPage, @Param("ew") Wrapper<Products> wrapper); }
7.在resources下面的mapper下创建ProductsDao.xml
<?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.azy.dao.ProductsDao"> <resultMap id="ProductsMap" type="com.azy.pojo.Products" autoMapping="true"> <id property="pid" column="pid" jdbcType="VARCHAR"/> <result property="pname" column="pname" jdbcType="VARCHAR"/> <result property="price" column="price" jdbcType="INTEGER"/> <result property="flag" column="flag" jdbcType="VARCHAR"/> <result property="category_id" column="category_id" jdbcType="VARCHAR"/> <association property="category" javaType="com.azy.pojo.Category" autoMapping="true"> <id column="cid" property="cid" jdbcType="VARCHAR"/> <result property="cname" column="cname" jdbcType="VARCHAR"/> </association> </resultMap> <select id="findPage" resultType="com.azy.pojo.Products" resultMap="ProductsMap"> select * from products p join category c on p.category_id=c.cid <if test="ew!=null"> <where> ${ew.sqlSegment} </where> </if> </select> </mapper>
8.在test包下的测试类中测试
package com.azy; import com.azy.dao.ProductsDao; import com.azy.dao.UserDao; import com.azy.pojo.Products; import com.azy.pojo.User; import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import org.junit.jupiter.ap编程i.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import javax.annotation.Resource; import java.util.List; @SpringBootTest class DemoApplicationTests { @Resource private UserDao userDao; @Test void contextLoads() { QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.likeRight("name","_z"); wrapper.or(); wrapper.between("age",10,20); wrapper.orderByDesc("age"); wrapper.select("name","age"); List<User> users = userDao.selectList(wrapper); users.forEach(System.out::println); } @Test public void delete(){ System.out.println(userDao.deleteById(5)); } @Test public void insert(){ User user = new User(); user.setAge(18); user.setName("cxk"); user.setEmail("123@qq.com"); System.out.println(userDao.insert(user)); } @Test public void update(){ User user = new User(); user.setAge(19); user.setName("azy"); user.setEmail("321@qq.com"); user.setId(6L); System.out.println(userDao.updateById(user)); } @Test public void selectById(){ System.out.println(userDao.selectById(4)); } @Test public void testPage(){ Page<User> page = new Page<>(1, 3);//current:当前第几页 size:每页显示条数 userDao.selectPage(page,null);//把查询分页的结构封装到page对象中 System.out.println("当前页的记录"+page.getRecords());//获取当前页的记录 System.out.println("获取总页数"+page.getPages());//获取当前页的总页数 System.out.println("获取总条数"+page.getTotal());//获取当前页的记录 } // ============================================================== @Resource private ProductsDao productsDao; @Test public void testQueryProductById(){ System.out.println(productsDao.selectById("p008")); } @Test public void testDelete(){ System.out.println(productsDao.deleteById("p008")); } @Test public void testInsert(){ Products products = new Products(); products.setPname("滑板鞋"); products.setFlag("2"); products.setPrice(8888); products.setCategory_id("c002"); products.setPid("p009"); System.out.println(produ编程客栈ctsDao.insert(products)); } @Test public void testUpdate(){ Products products = new Products(); products.setPname("篮球"); products.setFlag("1"); 编程客栈 products.setPrice(188); products.setCategory_id("c002"); products.setPid("p009"); System.out.println(productsDao.updateById(products)); } @Test public void testProductsPage(){ Page<Products> page = new Page<>(1, 3);//current:当前第几页 size:每页显示条数 productsDao.selectPage(page,null);//把查询分页的结构封装到page对象中 System.out.println("当前页的记录"+page.getRecords());//获取当前页的记录 System.out.println("获取总页数"+page.getPages());//获取当前页的总页数 System.out.println("获取总条数"+page.getTotal());//获取当前页的记录 } @Test public void testProductsPage2(){ Page<Products> page=new Page<>(1,3); QueryWrapper<Products> wrapper=new QueryWrapper<>(); wrapper.gt("price",1000); productsDao.findPage(page,wrapper); System.out.println("当前页的记录"+page.getRecords());//获取当前页的记录 System.out.println("获取总页数"+page.getPages());//获取当前页的记录 System.out.println("获取总条数"+page.getTotal());//获取当前页的记录 } }
9.最后运行测试类
测试完成
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