Mybatis以及MyBatis-plus使用、区别，与Spring集成

mybatis-plus是mybatis的增强版，其中对于简单的CRUD操作及分页查询有极其简便的配置方式，大大增加了开发效率,并且不影响之前mybatis的使用习惯。

maven引入

	<dependency>
      <groupId>com.baomidougroupId>
      <artifactId>mybatis-plusartifactId>
      <version>3.2.0version>
    dependency>
   <dependency>
   <dependency>
      <groupId>com.github.pagehelpergroupId>
      <artifactId>pagehelperartifactId>
      <version>5.1.2version>
    dependency>
    <dependency>
      <groupId>log4jgroupId>
      <artifactId>log4jartifactId>
      <version>1.2.17version>
    dependency>

虽然mybatis-plus 有原生的分页插件类可供使用，但是也只是供
BaseMapper，如果是自己写在mapper.xml文件中，则其分页插件就不起作用，就要使用第三方分页插件PageHelper。
加入log4j可以查看每次执行的sql语句，要配置log4j.properties文件

log4j.rootLogger=INFO,stdout,R

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
#log4j.appender.stdout.layout.ConversionPattern=  %d{yy-MM-dd HH:mm:ss:SSSS} %p %C{1}.%M(%L) | %m%n
log4j.appender.stdout.layout.ConversionPattern=  %d %-5p %c.%M:%L - %m%n


log4j.logger.com.ibatis=DEBUG
log4j.logger.com.ibatis.common.jdbc.SimpleDataSource=DEBUG
log4j.logger.com.ibatis.common.jdbc.ScriptRunner=DEBUG
log4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientDelegate=DEBUG
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG

Mybatis-config.xml编写

<configuration>
    
    <settings>
        
        <setting name="useGeneratedKeys" value="true" />

        
        <setting name="useColumnLabel" value="true" />

        
        <setting name="mapUnderscoreToCamelCase" value="true" />
        <setting name="logImpl" value="STDOUT_LOGGING" />
    settings>
    <plugins>
        
        <plugin interceptor="com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor">
                <property name="dialecType" value="mysql" />
        plugin>
        
        <plugin interceptor="com.github.pagehelper.PageInterceptor">
        plugin>
    plugins>
configuration>

此处pageHelper仅仅是注册一下类就可以了，无需写方言，自动匹配，而mybatis-plus的原生分页要初始化一下方言类型。

Mapper.xml配置文件以及Mapper接口编写

<?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.xr.dao.ContractStampUpdateMapper">
</mapper>

public interface ContractStampUpdateMapper extends BaseMapper<ContractStampUpdate> {
}

由于Mybatis-plus有BaseMapper类进行基本的CRUD所以可以不用Mapper文件内容可以不用写，同样的Mapper接口类也不用写实际内容，但是必须要有而且接口必须继承BaseMapper接口。

pojo的编写

package com.xr.pojo;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;

import java.util.Date;


@TableName("contract_stamp_update")
public class ContractStampUpdate {
    @TableId(value = "ID",type = IdType.AUTO)
    private Long id;
    @TableField("CONTRACT_ID")
    private String contractId;
    @TableField("CONTRACT_NO")
    private String contractNo;
    @TableField("PRINT_TYPE")
    private String printType;
    @TableField("PRINT_URL")
    private String printUrl;
    @TableField("VIEW_URL")
    private String viewUrl;
    @TableField("PRINT_CODE")
    private String printCode;
    @TableField("PRINT_NAME")
    private String printName;
    @TableField("PRINT_DATE")
    private Date printDate;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getContractId() {
        return contractId;
    }

    public void setContractId(String contractId) {
        this.contractId = contractId;
    }

    public String getContractNo() {
        return contractNo;
    }

    public void setContractNo(String contractNo) {
        this.contractNo = contractNo;
    }

    public String getPrintType() {
        return printType;
    }

    public void setPrintType(String printType) {
        this.printType = printType;
    }

    public String getPrintUrl() {
        return printUrl;
    }

    public void setPrintUrl(String printUrl) {
        this.printUrl = printUrl;
    }

    public String getViewUrl() {
        return viewUrl;
    }

    public void setViewUrl(String viewUrl) {
        this.viewUrl = viewUrl;
    }

    public String getPrintCode() {
        return printCode;
    }

    public void setPrintCode(String printCode) {
        this.printCode = printCode;
    }

    public String getPrintName() {
        return printName;
    }

    public void setPrintName(String printName) {
        this.printName = printName;
    }

    public Date getPrintDate() {
        return printDate;
    }

    public void setPrintDate(Date printDate) {
        this.printDate = printDate;
    }
}

注解写好自动与数据库进行匹配，这就是接口继承BaseMapper之后无需编写mapper.xml的奥妙。

Spring的Application.xml文件编写

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context.xsd
	http://www.springframework.org/schema/tx
	http://www.springframework.org/schema/tx/spring-tx.xsd">
 <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>classpath:application.propertiesvalue>
            list>
        property>
    bean>
     <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${jdbc.connection.driverclassname}" />
        <property name="url" value="${jdbc.connection.url}"/>
        <property name="username" value="${jdbc.connection.name}"/>
        <property name="password" value="${jdbc.connection.password}"/>
    bean>
    
        
        
        
    
    <bean id="sqlSessionFactory" class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean">
        
        <property name="dataSource" ref="dataSource" />
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        
         <property name="mapperLocations" value="classpath:mappers/*.xml"/>
    bean>

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
        <property name="basePackage" value="com.xr.dao" />
    bean>
    
    <context:component-scan base-package="com.xr" />
beans>

由此可以看到mybaits与mybatis-plus 的spring配置时的区别，主要在sqlSessionFactory上，bean使用的class不同。

实操

 @Autowired
 public class Controller1 {
    ContractStampUpdateMapper mapper;
    @RequestMapping(value = "/test" ,produces = "application/json;charset=utf-8",method = RequestMethod.POST)
    @ResponseBody
    public  String one() throws JsonProcessingException {

        QueryWrapper<ContractStampUpdate> wrapper = new QueryWrapper<>();
        Page page = new Page(1,2);
        IPage iPage = mapper.selectPage(page, wrapper);
        ObjectMapper omapper = new ObjectMapper();
        String s = omapper.writeValueAsString(iPage);
        System.out.println(s);

        return s;
    	}
   }

输出

{
    "records": [
        {
            "id": 294,
            "contractId": "20191107150003",
            "contractNo": "573455149800",
            "printType": "2",
            "printUrl": null,
            "viewUrl": null,
            "printCode": null,
            "printName": null,
            "printDate": 1573427454000
        },
        {
            "id": 295,
            "contractId": "20191107150003",
            "contractNo": "573455149800",
            "printType": "3",
            "printUrl": "",
            "viewUrl": null,
            "printCode": null,
            "printName": null,
            "printDate": 1573427702000
        }
    ],
    "total": 7,
    "size": 2,
    "current": 1,
    "orders": [],
    "searchCount": true,
    "pages": 4
}