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项目准备
1.JDK1.8 安装配置 2.Maven 3.6安装配置 3.IDEA 2019安装 4.Navicat 12安装 5.MariaDB 安装 支撑MySQL 数据库首先搭建一个
然后在src/main/java 中分别添加不同的层级目录,在这个小demo中,测试的用例:User Worker项目所需要的maven 依赖,pom,.xml文件
4.0.0 org.springframework.boot spring-boot-starter-parent 2.1.6.RELEASE com.circle demo 1.0.0 dtdream Demo project for Spring Boot 1.8 org.springframework.boot spring-boot-starter-web org.projectlombok lombok 1.16.20 provided org.springframework.boot spring-boot-starter-test test mysql mysql-connector-java 5.1.40 org.springframework.boot spring-boot-starter-data-jpa org.mybatis.spring.boot mybatis-spring-boot-starter 1.3.1 org.flywaydb flyway-core org.springframework.boot spring-boot-starter-jdbc org.springframework.boot spring-boot-devtools true org.springframework.boot spring-boot-maven-plugin maven-compiler-plugin 3.7.0 org.flywaydb flyway-maven-plugin 5.2.4 org.springframework springloaded 1.2.6.RELEASE true
编写两个类 User 和 Worker
import lombok.Data;@Datapublic class User { private String name; private Integer id; private Integer age; private String password; private String email; public User(String name) { this.name = name; } public User() { super(); } public User(String name, Integer id, Integer age, String password, String email) { this.name = name; this.id = id; this.age = age; this.password = password; this.email = email; } @Override public String toString() { return "Student{" + "name='" + name + '\'' + ", id='" + id + '\'' + ", age=" + age + '}'; }}
import lombok.Data;@Datapublic class Worker { private Integer id; private String name; private String password; private String email; public Worker(String name) { this.name = name; } public Worker(Integer id, String name, String password, String email) { this.id = id; this.name = name; this.password = password; this.email = email; } @Override public String toString() { return "Worker{" + "id=" + id + ", name='" + name + '\'' + ", password='" + password + '\'' + ", email='" + email + '\'' + '}'; }}
该依赖在pom.xml文件中已经有了依赖,@Data注解在类上, 为类提供读写属性(get,set), 此外还提供了 equals()、hashCode()、toString() 方法
@Mapper注解,标注该类属于DAO层,目的就是为了不再写mapper映射文件,添加了@Mapper注解之后这个接口在编译时会生成相应的实现类。
注意:这个接口中不可以定义同名的方法,因为会生成相同的id,也就是说这个接口是不支持重载的import com.circle.demo.model.Worker;import org.apache.ibatis.annotations.Mapper;@Mapperpublic interface WorkerDao { Worker getWorkerById( Integer id);}
该层级结构一般用来书写接口,这一层的结构添加**@Service注解进行容器管理**
import com.circle.demo.model.Worker;import org.springframework.stereotype.Service;@Servicepublic interface WorkerService { Worker getWorkerById(Integer id);}
该层是对Service层接口的实现类,添加**@Service注解进行容器管理**
import com.circle.demo.dao.WorkerDao;import com.circle.demo.model.Worker;import com.circle.demo.service.WorkerService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;@Servicepublic class WorkServiceImpl implements WorkerService { @Autowired(required=false) WorkerDao workerDao; @Override public Worker getWorkerById(Integer id) { return workerDao.getWorkerById(id); }}
注意:@Autowired(required=false)
1.在使用spring开发过程中,我们基本上都是使用@Autowired这个注解,用来注入已有的bean,且默认的required=true 2.@Autowired(required=false):表示忽略当前要注入的bean,如果有直接注入,没有跳过 3.解析:在容器的启动过程中,会初始化很多bean,这也是spring的核心之一(IOC)。但是在注入的过程中,扫描到公共方法中要注入的bean,并未找到,强行注入就会注入失败。所以我们采取的思想就是有bean就注入,没有就不注入。解决办法就是@Autowired(required=false)。@Autowired()@Qualifier("baseDao")private BaseDao baseDao;
@Resource(name="baseDao")private BaseDao baseDao;
这里编写简单胡两个测试方法,hello方法,getWorkerById方法
@RestController 注解作用 就是@ResponseBody + @Controller 注解 将返回的数据以json的形式传递到网页前端 @RequestMapping 表示该controller请求的路径,在类上添加该注解表示,该类的所有方法的统一路径,其路径下可以有子路径,常用参数RequestMethod,其值可以有,RequestMethod.POST, RequestMethod.GET,不一一列举 @PostMapping @GetMapping 则表示RequestMapping 的Post请求,Get 请求 @PathVariable 表示url路径请求的时候,传入的值1,形式为url /id/1 @RequestParam 表示请求的路径 传入的参数值1,形式为url ?id=1import com.circle.demo.model.Worker;import com.circle.demo.service.WorkerService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.*;@RestControllerpublic class WorkerController { @Autowired WorkerService workerService ; @GetMapping( "/hello") public String hello(){ System.out.println("hello"); return "hello"; } @GetMapping("/id/{id}") public Worker getWorkerById(@PathVariable("id") Integer id){ System.out.println(workerService.getWorkerById(id).toString()); return workerService.getWorkerById(id); }}
Mybatis 文件的配置,mapper.xml 以及mybatis 在application.yml文件的配置
@MapperScan(basePackages = {“com.circle.demo.dao”}) 扫描标注@Maper的类
import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication@MapperScan(basePackages = {"com.circle.demo.dao"})public class DtdreamApplication { public static void main(String[] args) { SpringApplication.run(DtdreamApplication.class, args); }}
#:占位符号,可以防止sql注入(替换结果会增加单引号‘’),解析为一个 JDBC 预编译语句(prepared statement)的参数标记符
美元符号 : s q l 拼 接 符 号 ( 替 换 结 果 不 会 增 加 单 引 号 ‘ ’ , :sql拼接符号(替换结果不会增加单引号‘’, :sql拼接符号(替换结果不会增加单引号‘’,{ } 仅仅为一个纯碎的 string 替换,在动态 SQL 解析阶段将会进行变量替换。使用场景:like和order by后使用,存在sql注入问题,需手动代码中过滤)注意:
大坑!!!WorkerMapper.xml文件中,id,type等不可以有多余的空格,否则报错
spring: datasource: password: root driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&mysqlEncoding=utf8 username: root hikari: minimum-idle: 5 maximum-pool-size: 20 jpa: show-sql: true hibernate: ddl-auto: create database-platform: org.hibernate.dialect.MySQL5InnoDBDialect flyway: baselineVersion: 1.0.0 outOfOrder: true locations: classpath:db/migration baselineOnMigrate: true enabled: truemybatis: #config-location: classpath:config/mybatis-config.xml mapper-locations: classpath:com/circle/mapper/*.xml #type-aliases-package: com.circle.demo.model
sql文件和mapper文件存放位置
flyway 自动化执行的脚本文件:V1.2.1__addworkertable.sql
SET FOREIGN_KEY_CHECKS=0;DROP TABLE IF EXISTS `auth_worker`;CREATE TABLE `auth_worker` ( `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键', `name` char(30) NULL COMMENT '姓名', `password` char(10) NULL COMMENT '密码', `email` char(30) NULL COMMENT '邮箱', PRIMARY KEY (`id`), KEY `IDX_NAME` (`name`)) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;INSERT INTO auth_worker (id, name, password, email) VALUES (1, '林炳文', '1234567@', 'ling20081005@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (2, 'evan', '123', 'fff@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (3, 'kaka', 'cadg', 'fwsfg@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (4, 'simle', 'cscs', 'fsaf@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (5, 'arthur', 'csas', 'fsaff@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (6, '小德', 'yuh78', 'fdfas@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (7, '小小', 'cvff', 'fsaf@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (8, '林林之家', 'gvv', 'lin@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (9, '林炳文', 'dfsc', 'ling2008@126.com');INSERT INTO auth_worker (id, name, password, email) VALUES (10, 'apple', 'uih6', 'ff@qq.com');DROP TABLE IF EXISTS `auth_user`;CREATE TABLE `auth_user` ( `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键', `name` char(30) NULL COMMENT '姓名', `password` char(10) NULL COMMENT '密码', `email` char(30) NULL COMMENT '邮箱', `age` int(11) NULL COMMENT '年龄', PRIMARY KEY (`id`), KEY `IDX_NAME` (`name`)) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
参考链接
转载地址:http://azcii.baihongyu.com/