记录一次批量操作（mybtatis+mysql）

      在进行mybatis批量操作时笔记。
      环境搭建（数据库更换mysql方便更改搜索引擎，h2默认的搜索（好像是MyISAM）对事物不友好）<?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>
<!--可在SqlSessionFactory中配置 -->
<typeAliases>
<package name="mybatis.model" />
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/test?useSSL=false" />
<property name="username" value="root" />
<property name="password" value="1234" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- 在application中统一注解 -->
<mapper resource="mapper/CityMapper.xml" />
<mapper resource="mapper/HotelMapper.xml" />
</mappers>
</configuration>

      使用mybatis批量插入时，有两个思路，一种是使用ExecutorType.BATCH，一种使用insert语句传递list。
ExecutorType.BATCH
       ExecutorType有三种类型：

SIMPLE  独立预处理（preparing 语句），每次单独提交
REUSE   重用preparing语句，每次单独提交
BATCH  重用preparing语句，批量提交
测试代码package mybatis;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import mybatis.model.City;

public class T {

public static void main(String[] args) {
SqlSession session = null;
try {
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()
.build(Resources.getResourceAsReader("mybatis-config.xml"));
session = sqlSessionFactory.openSession(ExecutorType.BATCH);
session.insert("insert", new City("a", "", ""));
session.insert("insert", new City("b", "", ""));
session.commit();
} catch (Exception e) {
session.rollback();
} finally {
session.close();
}
}

}
         autoCommit默认为false（true对batch不生效），即两次insert都在一个事物以内。
simplemybatis.mapper.CityMapper.insert - ==> Preparing: insert into city (name,state,country) values (?,?,?)
mybatis.mapper.CityMapper.insert - ==> Parameters: a(String), (String), (String)
mybatis.mapper.CityMapper.insert - <== Updates: 1
mybatis.mapper.CityMapper.insert - ==> Preparing: insert into city (name,state,country) values (?,?,?)
mybatis.mapper.CityMapper.insert - ==> Parameters: b(String), (String), (String)
mybatis.mapper.CityMapper.insert - <== Updates: 1reusemybatis.mapper.CityMapper.insert - ==> Preparing: insert into city (name,state,country) values (?,?,?)
mybatis.mapper.CityMapper.insert - ==> Parameters: a(String), (String), (String)
mybatis.mapper.CityMapper.insert - <== Updates: 1
mybatis.mapper.CityMapper.insert - ==> Parameters: b(String), (String), (String)
mybatis.mapper.CityMapper.insert - <== Updates: 1batchmybatis.mapper.CityMapper.insert - ==> Preparing: insert into city (name,state,country) values (?,?,?)
mybatis.mapper.CityMapper.insert - ==> Parameters: a(String), (String), (String)
mybatis.mapper.CityMapper.insert - ==> Parameters: b(String), (String), (String)插入异常package mybatis;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import mybatis.model.City;

public class T {

public static void main(String[] args) {
SqlSession session = null;
try {
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()
.build(Resources.getResourceAsReader("mybatis-config.xml"));
session = sqlSessionFactory.openSession(ExecutorType.BATCH);
session.insert("insert", new City("a", "", ""));
//会报错，ExecutorType=simple or re
4000
use不会进行commit，因此不会入库
session.insert("insert", new City(null, "", ""));
session.commit();
} catch (Exception e) {
//此处不需要进行rollback，simple或reuse没有进行commit，batch批量操作有错误也不会入库
//session.rollback();
} finally {
session.close();
}
}

}         一旦进行了commit，rollback将不起作用。当出错时，自动回滚。mybatis.mapper.CityMapper.insert - ==> Preparing: insert into city (name,state,country) values (?,?,?)
mybatis.mapper.CityMapper.insert - ==> Parameters: a(String), (String), (String)
mybatis.mapper.CityMapper.insert - <== Updates: 1
mybatis.mapper.CityMapper.insert - ==> Preparing: insert into city (name,state,country) values (?,?,?)
mybatis.mapper.CityMapper.insert - ==> Parameters: null, (String), (String)
org.apache.ibatis.transaction.jdbc.JdbcTransaction - Rolling back JDBC Connection [com.mysql.jdbc.JDBC4Connection@55e26b7f]
org.apache.ibatis.transaction.jdbc.JdbcTransaction - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@55e26b7f]
org.apache.ibatis.transaction.jdbc.JdbcTransaction - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@55e26b7f]
org.apache.ibatis.datasource.pooled.PooledDataSource - Returned connection 1440902015 to pool.      其实此处的rollback没有什么用，rollback要保证在commit之前使用，对于autoCommit=true无作用，autoCommit=false，出错了，没有进行commit，不需要进行rollback的。特殊需求，也插入时，发现错误，需要回滚，此时才使用rollback。列举一处rollback的test。package mybatis;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import mybatis.model.City;

public class T {

public static void main(String[] args) {
SqlSession session = null;
try {
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()
.build(Resources.getResourceAsReader("mybatis-config.xml"));
session = sqlSessionFactory.openSession(ExecutorType.BATCH);
List<City> list = new ArrayList<>();
for (int i = 0; i < 10; i++) {
list.add(new City(i + "", "", ""));
// 添加一个错误
if (i == 5) {
list.add(new City(null, "", ""));
}
}
// 批量添加，一次添加2个
int i = 0;
while (i < list.size()) {
int end = Math.min(i + 2, list.size());
List<City> subList=null;
try {
subList = list.subList(i, end);
for (City city : subList) {
session.insert("insert", city);
}
session.commit();
} catch (Exception e) {
for (City city : subList) {
System.out.println("uninsert : "+city.getName());
}
session.rollback();
}
i = end;
}
} catch (Exception e) {

} finally {
session.close();
}
}

}
         name=6与name=null作为同一批数据进行commit，当使用session.rollback，name=null因为语句错误没有commit成功，name=6也被回滚。当不使用session.rollback，name=6没有被回滚，commit成功。
       commit / rollback这两个命令用的时候要小心。 commit / rollback 都是用在执行 DML语句（INSERT / DELETE / UPDATE / SELECT ）之后的。DML 语句，执行完之后，处理的数据，都会放在回滚段中（除了 SELECT 语句），等待用户进行提交（commit）或者回滚 （rollback），当用户执行 commit / rollback后，放在回滚段中的数据就会被删除。

list参数进行批量提交 <insert id="batchinsert" parameterType="java.util.List">
<selectKey resultType ="java.lang.Long" keyProperty= "id" order= "AFTER">
SELECT LAST_INSERT_ID()
</selectKey >
insert into city (name,state,country)
VALUES
<foreach collection="list" item="c" index="index" separator=",">
(#{c.name},#{c.state},#{c.country})
</foreach>
</insert>

package mybatis;

import java.util.ArrayList;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import mybatis.model.City;

public class T {

public static void main(String[] args) {
SqlSession session = null;
try {
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()
.build(Resources.getResourceAsReader("mybatis-config.xml"));
session = sqlSessionFactory.openSession(ExecutorType.SIMPLE,true);
List<City> list = new ArrayList<>();
list.add(new City("a", "", ""));
list.add(new City("b", "", ""));
session.insert("batchinsert",list);
} catch (Exception e) {
} finally {
session.close();
}
}

}