Spring Boot基础入门之基于注解的Mybatis

前言

今天学习下springboot集成mybatis,集成mybatis一般有两种方式，一个是基于注解的一个是基于xml配置的。今天先了解下基于注解的mybatis集成。下面话不多说了，来一起看看详细的介绍吧

一、引入依赖项

因为是mybatis嘛,肯定是要有mybatis相关的,同时用的是mysql,所以也需要引入mysql相关的。

<!-- 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、创建model

这里创建了一个user的model,这样方便与数据库的表对照，这里在mysql中创建了一个名为mybatis的数据库,里面创建了一个user的表.同时创建了枚举类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、创建mapper

这里需要把model与操作数据库的sql对照起来，用什么对照呢?那就需要创建一个mapper.这里有增删改查。

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、配置扫描

上面配置了mapper,那怎么让系统知道mapper放在哪里呢?于是有了@mapperscan注解。

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、创建controller

这里创建了usercontroller,一个是显示所有用户,一个是新增一个用户之后再显示所有用户。

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、数据库配置

上面mapper也设置了,model也设置了,那要与数据库交互，肯定要配置数据库地址这些信息吧。这里在运行的时候还报了一个错误.nested exception is java.sql.sqlexception: the server time zone value 'öð¹ú±ê׼걼ä' 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中设置了下时区:set global time_zone='+8:00';

spring.mvc.view.prefix=/view/

spring.mvc.view.suffix=.jsp
mybatis.type-aliases-package=com.example.model

spring.datasource.driverclassname = com.mysql.cj.jdbc.driver
spring.datasource.url = jdbc:mysql://localhost:3306/mybatis
spring.datasource.username = root
spring.datasource.password = 123456

七、创建页面显示

这里还是按照上一博客用jsp显示数据。

<%@ 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>年龄</th><th>性别</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、测试

这里先在浏览器打开http://localhost:8080/user/alluser.do，可以看到用户列表,然后输入http://localhost:8080/user/insert.do，就会看到列表显示多了一行数据。

九、小结

使用基于注解的集成mybatis比较省事方便，但有利有弊，对于多表相连的可能就不太方便，使用基于xml配置的可能就更会好些。

好了，以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对的支持。