Spring Boot基礎入門之基於註解的Mybatis

前言

今天學習下SpringBoot集成mybatis,集成mybatis一般有兩種方式，一個是基於註解的一個是基於xml配置的。今天先了解下基於註解的mybatis集成。下面話不多說了，來一起看看詳細的介紹吧

一、引入依賴項

因為是mybatis嘛,肯定是要有mybatis相關的,同時用的是mysql,所以也需要引入mysql相關的。

 <!-- https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter --> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.11</version> </dependency>

二、創建model

這裡創建了一個User的model,這樣方便與數據庫的表對照，這裡在mysql中創建了一個名為mybatis的數據庫,裡面創建了一個user的表.同時創建了枚舉類UserSexEnum.

 CREATE TABLE `user` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(20) DEFAULT NULL, `age` int(11) DEFAULT NULL, `sex` varchar(20) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;

 package com.example.model;import java.io.Serializable;public class User implements Serializable{ @Override public String toString() { // TODO Auto-generated method stub return "User [id=" + Id + ", name=" + Name + ", age=" + Age + "]"; } public int getId() { return Id; } public void setId(int id) { Id = id; } public String getName() { return Name; } public void setName(String name) { Name = name; } public int getAge() { return Age; } public void setAge(int age) { Age = age; } private int Id; private String Name; private int Age; private UserSexEnum Sex; public UserSexEnum getSex() { return Sex; } public void setSex(UserSexEnum sex) { Sex = sex; }}

 package com.example.model;public enum UserSexEnum { MAN, WOMAN}

三、創建Mapper

這裡需要把model與操作數據庫的sql對照起來，用什麼對照呢?那就需要創建一個mapper.這裡有增刪改查。

 package com.example.mapper;import java.util.List;import org.apache.ibatis.annotations.Delete;import org.apache.ibatis.annotations.Insert;import org.apache.ibatis.annotations.Result;import org.apache.ibatis.annotations.Results;import org.apache.ibatis.annotations.Select;import org.apache.ibatis.annotations.Update;import com.example.model.*;;public interface UserMapper { @Select("SELECT * FROM user") @Results({ @Result(property = "Sex", column = "sex", javaType = UserSexEnum.class), @Result(property = "Name", column = "name") }) List<User> getAll(); @Select("SELECT * FROM user WHERE id = #{id}") @Results({ @Result(property = "Sex", column = "sex", javaType = UserSexEnum.class), @Result(property = "Name", column = "name") }) User getOne(int id); @Insert("INSERT INTO user(name,age,sex) VALUES(#{name}, #{age}, #{sex})") void insert(User user); @Update("UPDATE user SET name=#{userName},age=#{age} WHERE id =#{id}") void update(User user); @Delete("DELETE FROM user WHERE id =#{id}") void delete(int id);}

四、配置掃描

上面配置了mapper,那怎麼讓系統知道mapper放在哪裡呢?於是有了@MapperScan註解。

 package com.example.demo;import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication@MapperScan("com.example.mapper")public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); }}

五、創建Controller

這裡創建了UserController,一個是顯示所有用戶,一個是新增一個用戶之後再顯示所有用戶。

 package com.example.demo;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import com.example.mapper.UserMapper;import com.example.model.User;import com.example.model.UserSexEnum;@Controller@RequestMapping("/user")public class UserController { @Autowired private UserMapper userMapper; @RequestMapping(value = "/alluser.do",method = RequestMethod.GET) public String getallusers(Model model) { List<User> users=userMapper.getAll(); model.addAttribute("users", users); return "userlist"; } @RequestMapping(value = "/insert.do",method = RequestMethod.GET) public String adduser(Model model) { User user=new User(); user.setName("cuiyw"); user.setAge(27); user.setSex(UserSexEnum.MAN); userMapper.insert(user); List<User> users=userMapper.getAll(); model.addAttribute("users", users); return "userlist"; }}

六、數據庫配置

上面mapper也設置了,model也設置了,那要與數據庫交互，肯定要配置數據庫地址這些信息吧。這裡在運行的時候還報了一個錯誤.nested exception is java.sql.SQLException: The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.在mysql中設置了下時區:set global time_zone='+8:00';

 spring.mvc.view.prefix=/view/spring.mvc.view.suffix=.jspmybatis.type-aliases-package=com.example.modelspring.datasource.driverClassName = com.mysql.cj.jdbc.Driverspring.datasource.url = jdbc:mysql://localhost:3306/mybatisspring.datasource.username = rootspring.datasource.password = 123456

七、創建頁面顯示

這裡還是按照上一博客用jsp顯示數據。

 <%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Insert title here</title></head><body> <table> <tr><th>名字</th><th>年齡</th><th>性別</th></tr> <c:forEach items="${users}" var="item"> <tr><td>${item.name}</td><td>${item.age}</td><td>${item.sex}</td></tr> </c:forEach> </table></body></html>

八、測試

這裡先在瀏覽器打開http://localhost:8080/user/alluser.do，可以看到用戶列表,然後輸入http://localhost:8080/user/insert.do，就會看到列表顯示多了一行數據。

九、小結

使用基於註解的集成mybatis比較省事方便，但有利有弊，對於多表相連的可能就不太方便，使用基於xml配置的可能就更會好些。

好了，以上就是這篇文章的全部內容了，希望本文的內容對大家的學習或者工作具有一定的參考學習價值，如果有疑問大家可以留言交流，謝謝大家對武林網的支持。