idea下mybatis的简单搭建和使用<转>

首先在IDEA中创建一个 Gradle Java项目，然后一直下一步。其实Gradle比Meaven好用的，Gradle可以用下面网站进行搜索

[https://package-search.jetbrains.com/]:

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创建好项目在build.gradle引用mybatis、log4j:log4j和mysql-connector-java包

plugins {
    id 'java'
}

group 'com.hwp'
version '1.0-SNAPSHOT'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.12'
    implementation 'org.mybatis:mybatis:3.5.5'
    implementation 'mysql:mysql-connector-java:5.1.25'
   implementation 'log4j:log4j:1.2.17' 
}

在main目录下创建java和resources文件夹，其中java文件夹为Sources Root属性，resources 文件夹为 ** Resources Root** 属性

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在resources文件夹中创建Configure.xml、db.properties和log4j.properties具体内容如下

Configure.xml文件为mybatis的配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
    <properties resource="db.properties"></properties>
    <typeAliases>

        <package name="com.hwp.bean"/>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="BookMapper.xml" />
    </mappers>

</configuration>

db.properties文件为数据库的配置文件

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/book?useSSL=false
jdbc.username=root
jdbc.password=hwp123456

log4j.properties为log4j的配置文件

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

在com.hwp.mapper包下创建BookMapper.java接口类

package com.hwp.mapper;

import com.hwp.bean.Book;

public interface BookMapper {
    public Book queryById(int  id);
}

8.在com.hwp.mapper.Impl包下创建实现类

package com.hwp.mapper.Impl;

import com.hwp.bean.Book;
import com.hwp.mapper.BookMapper;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

public class BookMapperImpl implements BookMapper {
    private  SqlSessionFactory sqlSessionFactory;

    public BookMapperImpl(SqlSessionFactory sqlSessionFactory) {
        this.sqlSessionFactory=sqlSessionFactory;
    }

    @Override
    public Book queryById(int id) {
        SqlSession sqlSession=null;
        Book  book = null;
        try {
            sqlSession=sqlSessionFactory.openSession();
     book=sqlSession.selectOne("com.hwp.mapper.BookMapper.queryById",id);

        } catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            if(sqlSession!=null){
                sqlSession.close();
            }
        }
        return book;
    }
}

创建实体类Book.java 字段名字和数据类型要和数据库对上，这个大家都知道的

    package com.hwp.bean;
    
    public class Book {
        private int id;
        private String bookName;
        private  double bookPrice;
        private    int  bookCount;
        private String  author;
        private int vend_id;
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getBookName() {
            return bookName;
        }
    
        public void setBookName(String bookName) {
            this.bookName = bookName;
        }
    
        public double getBookPrice() {
            return bookPrice;
        }
    
        public void setBookPrice(double bookPrice) {
            this.bookPrice = bookPrice;
        }
    
        public int getBookCount() {
            return bookCount;
        }
    
        public void setBookCount(int bookCount) {
            this.bookCount = bookCount;
        }
    
        public String getAuthor() {
            return author;
        }
    
        public void setAuthor(String author) {
            this.author = author;
        }
    
        public int getVend_id() {
            return vend_id;
        }
    
        public void setVend_id(int vend_id) {
            this.vend_id = vend_id;
        }
    
        @Override
        public String toString() {
            return "Book{" +
                    "id=" + id +
                    ", bookName='" + bookName + '\'' +
                    ", bookPrice=" + bookPrice +
                    ", bookCount=" + bookCount +
                    ", author='" + author + '\'' +
                    ", vend_id=" + vend_id +
                    '}';
        }
    }

10.数据库预览

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CREATE TABLE `book_info` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `bookName` varchar(200) NOT NULL,
  `bookPrice` double NOT NULL,
  `bookCount` int(11) NOT NULL,
  `author` varchar(45) NOT NULL,
  `vend_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=utf8;

11.在test文件夹下写一个test类，用于测试

package com.hwp;

import com.hwp.bean.Book;
import com.hwp.mapper.BookMapper;
import com.hwp.mapper.Impl.BookMapperImpl;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.apache.ibatis.io.Resources;
import org.junit.Test;

import java.io.InputStream;

public class Test_mybatis0 {
    SqlSessionFactory sqlSessionFactory;
    @Before
    public   void  read() throws  Exception{
        InputStream inputStream=Resources.getResourceAsStream("Configure.xml");
        sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
    }
    @Test
    public  void test01(){
        BookMapper bookMapper=new BookMapperImpl(sqlSessionFactory);
        Book book=bookMapper.queryById(20);
        System.out.println("BOOK:"+book);
    }
}

测试成功，会有如下打印

BOOK:Book{id=20, bookName='9书名d', bookPrice=37.0, bookCount=50, author='作者三', vend_id=1001}