Mybatis（ieda）

• 一款优秀的持久层框架


• 官网：Mybatis-3官网

1. Maven仓库：

mavenRepositroy

2. 数据库：

CREATE TABLE `user`(
`id` INT(20) NOT NULL PRIMARY KEY,
`name` VARCHAR(30) DEFAULT NULL,
`pwd` VARCHAR(30) DEFAULT NULL
)ENGINE=INNODB CHARSET=utf8;
INSERT INTO `user`(`id`,`name`,`pwd`) VALUES
(1,'lix','123456'),
(2,'admin','123456'),
(3,'root','123456')


3. 导入依赖



junit
junit
4.12
test


mysql
mysql-connector-java
5.1.47


com.mchange
c3p0
0.9.5.2


javax.servlet
servlet-api
2.5


javax.servlet.jsp
jsp-api
2.2


javax.servlet
jstl
1.2


org.mybatis
mybatis
3.5.4


org.mybatis
mybatis-spring
2.0.5


org.springframework
spring-webmvc
5.2.12.RELEASE


org.springframework
spring-jdbc
5.2.8.RELEASE




4. 1、添加applicationContext表头

   
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd">




   4.2、添加mybatis配置文件-----表头：

   
   


PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">





4.3、添加database.properties文件

jdbc.driver=com.mysql.cj.jdbc.Driver
#如果使用的是MySQL8.0+ ，需要增加一个时区的配置 &serverTime=Asia/Shanghai
jdbc.url=jdbc:mysql://localhost:3306/ssmbuild?useSSL=true&useUnicode=true&characterEncoding=utf-8
jdbc.username=******
jdbc.password=******


4.4、添加mapper表头


PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">





4.5、编写dao层-----

• 接口

package com.lix.dao;
import com.lix.pojo.Books;
import org.apache.ibatis.annotations.Param;
import java.util.List;
public interface BookMapper {
int addBook(Books books);
int deleteBookById(@Param("bookId") int id);
int updateBook(Books books);
Books queryBookById(@Param("bookId") int id);
List queryAllBook();
}


• 实现

  
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">


insert into ssmbuild.books (bookName,bookCounts,detail)
values (#{bookName},#{bookCounts},#{detail});


delete from ssmbuild.books where bookID = #{bookId}


update ssmbuild.books
set bookName=#{bookName},bookCounts=#{bookCounts},detail=#{detail}
where bookID=#{bookID}


select * from ssmbuild.books
where bookID = #{bookId}


select * from ssmbuild.books




  4.6、编写service层------

  
  
  
  
  • 接口
  
  

  package com.lix.service;
import com.lix.pojo.Books;
import org.apache.ibatis.annotations.Param;
import java.util.List;
public interface BookService {
int addBook(Books books);
int deleteBookById(int id);
int updateBook(Books books);
Books queryBookById(int id);
List queryAllBook();
}

  

  
  

  • 实现

    package com.lix.service;
import com.lix.dao.BookMapper;
import com.lix.pojo.Books;
import java.util.List;
public class BookServiceImpl implements BookService {
private BookMapper bookMapper;
public void setBookMapper(BookMapper bookMapper) {
this.bookMapper = bookMapper;
}
public int addBook(Books books) {
return bookMapper.addBook(books);
}
public int deleteBookById(int id) {
return bookMapper.deleteBookById(id);
}
public int updateBook(Books books) {
return bookMapper.updateBook(books);
}
public Books queryBookById(int id) {
return bookMapper.queryBookById(id);
}
public List queryAllBook() {
return bookMapper.queryAllBook();
}
}


    ------mybatis层完结

    ------spring层开始-----

    
    
  
  
  
  

5.spring整合dao层


xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cOntext="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd">

















































6.spring整合service层


xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cOntext="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd">























7.spring整合controller层


xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cOntext="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">














------项目框架搭建完成-----

1. 报错：

   Could not find resource org/mybatis/example/mybatis-config.xml

   

• 解决：纯配置文件路径错误，检查路径即可

  
  



• 报错：

  org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.io.IOException: Could not find resource

  

  
  

  • 解决：在pom.xml中加入以下配置

    


src/main/resources

**/*.properties
**/*.xml

true


src/main/java

**/*.properties
**/*.xml

true




    

    
    
    8. log4j配置文件
    
    
    
    
  
  
  
  

#将等级为DEBUG的日志信息输出到console和file这两个目的地，console和file的定义在下面的代码
log4j.rootLogger=DEBUG,console,file
#控制台输出的相关设置
log4j.appender.cOnsole= org.apache.log4j.ConsoleAppender
log4j.appender.console.Target = System.out
log4j.appender.console.Threshold = Debug
log4j.appender.console.layout = org.apache.log4j.PatternLayout
log4j.appender.console.layout.COnversionPattern= [%c]-%m%n
#文件输出的相关设置
log4j.appender.file = org.apache.log4j.RollingFileAppender
log4j.appender.file.File = ./log/lix.log
log4j.appender.file.MaxFileSize = 10mb
log4j.appender.file.Threshold = DEBUG
log4j.appender.file.layout = org.apache.log4j.PatternLayout
log4j.appender.file.layout.COnversionPattern= [%p][%d{yy-mm-dd}][%c]%m%n
#日志输出级别
log4j.logger.org.mybatis = DEBUG
log4j.logger.java.sql = DEBUG
log4j.logger.java.sql.Statement = DEBUG
log4j.logger.java.sql.ResultSet = DEBUG
log4j.logger.java.sql.PreparedStatement = DEBUG


二.注解CRUD

package com.lix.dao;
import com.lix.pojo.User;
import org.apache.ibatis.annotations.*;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* program mybatis-01
* @author lix
*/
public interface UserMapper {
/**
* getUsers
* @return
*/
@Select("select * from user")
List getUsers();
/**
*
* getUserById
* @param id
* @param name
* @return
* 方法存在多个参数，
*/
@Select("select * from user where id=#{id}")
User getUserById(@Param("id") int id, @Param("name") String name);
/**
* addUser
* @param map
* @return
*/
@Insert("insert into user(id,name,pwd) values(#{id},#{name},#{pwd})")
int addUser(Map map);
/**
* updateUser
* @param map
* @return
*/
@Update("update user set name = #{name},pwd=#{pwd} where id = #{id}")
int updateUser(Map map);
/**
* deleteUse
* @param id
* @return
*/
@Delete("delete from user where id = #{id}")
int deleteUse(@Param("id") int id);
}


【注意：我们必须要把核心配置类（UserMapper.java）绑定到核心配置文件中（mybatis-config.xml）】

1. 关于@Param()注解

   
   
   
   
   • 基本类型的参数或者String类型，需要加
   
   
   • 引用类型不需要加
   
   
   • 如果只有一个基本类型的话，可以忽略，建议加
   
   
   • 我们在SQL中引用的就是我们这里的的@Param()中设定的属性名
   
   
   
   


2. 
   

   {} 可以很大程度的防止sql注入 ${}
   




3. Lombok

   
   
   
   

   • Project Lombok is a java library that automatically plugs into your editor and build tools, spicing up your java.
     
     Never write another getter or equals method again, with one annotation your class has a fully featured builder, Automate your logging variables, and much more.

     
     
     
     

     • Project Lombok是一个java库，它可以自动插入到你的编辑器和构建工具中，为您的java注入新的活力。

       不要再编写其他getter或equals方法，有了一个注释，类就有了功能齐全的构建器、自动化日志变量等等。

       
       
     
     
     
     
   
   

   • package com.lix.dao;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
/**
* program mybatis-02
* @author lix
* description 加在类上所有属性都加，加在属性上，只有属性加
*/
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private int id;
private String name;
private String pwd;
}

     

   
   
   
   

4.1、按照查询嵌套处理


select * from student









select * from teacher where id = #{tid};



三.动态SQL


select * from mybatis.user


title =1