前言
前面参照SpringBoot官网,自动生成了简单项目点击打开链接
配置数据库和代码遇到的问题
问题1:cannot load driver class :com.mysql.jdbc.Driver不能加载mysql
原因:没有添加依赖
解决:pom.xml添加依赖
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency>
问题2:Consider defining a bean of type 'com.xx.dao.XxDao' in your configuration.注入UserDao失败
原因:UserDao没有添加注解
解决:在接口UserDao外层加上注解:@Mapper
问题3:controller中注入service失败
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.boot.service.DemoService] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
原因:application.java文件默认扫描相同包名下的service,dao。
解决:application.java文件添加注解:@ComponentScan(basePackages = "com.xxx")
配置Mysql数据库
在pom.xml添加依赖
<dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.2.0</version> </dependency>
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency>
在application.properties添加
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/girls spring.datasource.username=root spring.datasource.password=chendashan spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.max-idle=10 spring.datasource.max-wait=10000 spring.datasource.min-idle=5 spring.datasource.initial-size=5 server.port=8080 server.session.timeout=10 server.tomcat.uri-encoding=UTF-8 mybatis.configLocations= classpath:mybatis-config.xml mybatis.mapper-locations=classpath:mapper/*.xml
建立库表省略,文章末尾附带
mapper文件
操作数据库,靠它完成。
<?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"> <!-- namespace用于绑定Dao接口 --> <mapper namespace="com.housekeeper.dao.UserDao"> <!-- 用用查询映射结果 --> <resultMap id="BaseResultMap" type="com.housekeeper.model.User" > <!-- column代表数据库列名,property代表实体类属性名 --> <result column="user_id" property="userId"/> <result column="user_name" property="userName"/> <result column="user_password" property="userPassword"/> </resultMap> <!-- 查询名字记录sql --> <select id="selectUserByUserName" parameterType="String" resultMap="BaseResultMap"> SELECT * FROM girls_info WHERE user_name = #{userName} </select> </mapper>
综上得知,UserDao通过映射文件mapper,执行了sql语句,返回了实体类User
UserDao接口
@Mapper public interface UserDao { /** * 根据user_name查询数据库 * (映射执行mapper文件中的sql语句selectUserByUserName) * @param userName 名字 * @return User */ public User selectUserByUserName(String userName); }
User实体类
public class User { private String userName; private String userPassword; public String getUserName() { return userName; } public void setName(String userName) { this.userName = userName; } public String getUserPassword() { return userPassword; } public void setPassword(String userPassword) { this.userPassword = userPassword; } }
逻辑结构
逻辑层在controller里处理,已知,执行Userdao的接口方法,即可操作数据库。为了更好处理逻辑分层,加入Service层,调用UserDao。在Service实现层,注入UserDao即可调用其方法。
@Service public class UserServiceImp implements UserService { @Autowired private UserDao userDao;//注入UserDao @Override public User selectUserByName(String userName) { return userDao.selectUserByUserName(userName); } }
public interface UserService { /** * 通过姓名查找User * @param userName * @return */ User selectUserByName(String useName); }
controller
最后,controller层对外提供接口,返回查询数据结果
@Controller public class UserController { @Autowired private UserService userService;//注入Service @ResponseBody @RequestMapping(value = "/login", method = RequestMethod.POST) public Map<String, Object> login(@RequestParam(value = "userName", required = true) String userName, @RequestParam(value = "userPassword", required = true) String userPassword) { Map<String,Object> result = new HashMap<String, Object>(); User user = null; String retCode = ""; String retMsg = ""; if(StringUtils.isEmpty(userName) || StringUtils.isEmpty(userPassword)){ retCode = "01"; retMsg = "用户名和密码不能为空"; }else{ user = userService.selectUserByName(userName); if(null == user){ retCode = "01"; retMsg = "用户不存在"; }else{ if(userPassword.equals(user.getUserPassword())){ retCode = "00"; retMsg = "登录成功"; }else{ retCode = "01"; retMsg = "密码有误"; } } } result.put(SystemConst.retCode, retCode); result.put(SystemConst.retMsg, retMsg); return result; } }
girls.sql文件
SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for `girls_info` -- ---------------------------- DROP TABLE IF EXISTS `girls_info`; CREATE TABLE `girls_info` ( `user_id` int(11) NOT NULL AUTO_INCREMENT, `user_name` varchar(30) NOT NULL, `user_password` varchar(10) NOT NULL, PRIMARY KEY (`user_id`) ) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8; -- ---------------------------- -- Records of girls_info -- ---------------------------- INSERT INTO `girls_info` VALUES ('1', '张帆', '123456'); INSERT INTO `girls_info` VALUES ('2', '李北', '123456'); INSERT INTO `girls_info` VALUES ('3', '陈珊珊', '123456'); INSERT INTO `girls_info` VALUES ('4', '王国立', '123456'); INSERT INTO `girls_info` VALUES ('5', '张三', '123456'); INSERT INTO `girls_info` VALUES ('6', '李四', '123456'); INSERT INTO `girls_info` VALUES ('7', 'Biligle', '123456');
下载地址:https://download.csdn.net/download/qq_29266921/10457479