教你手把手实现springboot中的mybatis增删查改方法

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MyBatis 是一款优秀的持久层框架，而在springboot中去使用它也是非常的方便.

1.首先先在springboot中的pom.xml中添加mybatis依赖和所需的数据源，在这里我使用的是alibaba的数据源

​

<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<scope>runtime</scope>
		</dependency>
		
		
		
		<dependency>
		<groupId>org.mybatis.spring.boot</groupId>
				<artifactId>mybatis-spring-boot-starter</artifactId>
				<version>1.3.2</version>
		</dependency>
		
		<dependency>
		<groupId>com.alibaba</groupId>
		<artifactId>druid</artifactId>
		<version>1.1.9</version>
		</dependency>
	</dependencies>

这个是一个mybatis的小demo的整个依赖，其中我需要的是

druid

mybatis-spring-boot-starter

mysql-connector-java

这三个依赖，然后配置好application.properties 连接到自己电脑上的数据库

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.url=jdbc:mysql://localhost:3306/mybatisdemo
spring.datasource.username=root
spring.datasource.password=123456

2.然后我们创建一个实体类和数据库里面的表的值一样

public class Book {
	private Integer id; 
	private String name; 
	private String author;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getAuthor() {
		return author;
	}
	public void setAuthor(String author) {
		this.author = author;
	} 
	
	
}

3.然后我们再创建一个BookMapper.xml来对数据库里面的数据进行操作

<?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.example.demo.ty.BookMapper">
<insert id="addBook" parameterType="com.example.demo.ty.Book">
INSERT INTO book(name,author) VALUES (#{name},#{author})
</insert>
<delete id="deleteBookById" parameterType="int">
DELETE FROM book WHERE id=#{id}
</delete>
<update id="updateBookById" parameterType="com.example.demo.ty.Book">
DELETE FROM book WHERE id=#{id}
</update>
<select id="getBookById" parameterType="int" resultType="com.example.demo.ty.Book">
SELECT * FROM book WHERE id=#{id} 
</select>
<select id="getAllBooks" resultType="com.example.demo.ty.Book"> 
SELECT * FROM book
 </select>
 </mapper >

4.然后我们再创建一个BookMapper.java来调用对应xml里面的sql语句

import java.util.List;

import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface  BookMapper {
 int addBook(Book book);
 int deleteBookById(int id);
 int updateBookById(Book book);
 Book getbookById();
 List<Book> getAllBooks() ; 
List<Book> queryBooksBySql(Map<String,Object> data);
}
 

其中我们的方法名一定要和xml里面的id相对应，不然会找不到对应的方法进而产生异常，而@Mapper这个注解也不能少

5.写一个BookService.java来进行调用BookMapper.java里面的方法

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class BookService {
	@Autowired
	BookMapper bookMapper; 
	public int addBook(Book book) {
		return bookMapper.addBook(book); 
}
	public int updateBook(Book book) { 
		return bookMapper.updateBookById(book) ; 
}
	public int deteleBook(int id) { 
		return bookMapper.deleteBookById(id) ; 
}
	public Book getBookByid(Integer id) { 
		return bookMapper.getbookById () ; 
	}
	public List<Book> getAllBooks () { 
		return bookMapper.getAllBooks (); 
	}

	}

其中@Autowired  注解是把BookMapper自动装载进来

6.最后在BookController.java进行调用

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class BookController {
	@Autowired
	BookService bookService;
//添加
		@GetMapping ("/addBool")
	public void addBook () {
		Book bl= new Book() ; 
		bl.setName ("西厢记");
		bl.setAuthor("魯迅");
		int i = bookService.addBook (bl) ; 
		System.out.println("addBook>>" + i); 
	}
//查询
	@GetMapping ("/findAll")
	public List<Book> findBook () {
	    List<Book>  bl = bookService.getAllBooks(); 
		System.out.println(bl);
		return bl; 
	}

	}
}

而这就完全了一个mybatis 的简单的增删改查demo了