Mybatis三种批量插入数据的方式

https://www.jb51.net/article/210089.htm 

 
这篇文章主要介绍了Mybatis的三种批量插入方式，帮助大家更好的理解和学习使用Java，感兴趣的朋友可以了解下
目录

 

1. 循环插入

mapper.xml：

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<?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.buhe.demo.mapper.StudentMapper">
  <insert id="insert" parameterType="Student">
    INSERT INTO tb_student (name, age, phone, address, class_id) VALUES (#{name},#{age},#{phone},#{address},#{classId})
  </insert>
</mapper>

mapper接口：

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public interface StudentMapper {
    int insert(Student student);
}

测试代码：

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@SpringBootTest
class DemoApplicationTests {
    @Resource
    private StudentMapper studentMapper;
 
    @Test
    public void testInsert(){
        //数据生成
        List<Student> studentList = createData(100);
 
        //循环插入
        long start = System.currentTimeMillis();
        studentList.stream().forEach(student -> studentMapper.insert(student));
        System.out.println(System.currentTimeMillis() - start);
    }
 
    private List<Student> createData(int size){
        List<Student> studentList = new ArrayList<>();
        Student student;
        for(int i = 0; i < size; i++){
            student = new Student();
            student.setName("小王" + i);
            student.setAge(18);
            student.setClassId(1);
            student.setPhone("1585xxxx669");
            student.setAddress("未知");
            studentList.add(student);
        }
 
        return studentList;
    }
}

2. foreach标签

mapper.xml：

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<?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.buhe.demo.mapper.StudentMapper">
  <insert id="insert" parameterType="Student">
    INSERT INTO tb_student (name, age, phone, address, class_id) VALUES (#{name},#{age},#{phone},#{address},#{classId})
  </insert>
 
  <insert id="insertBatch">
    INSERT INTO tb_student (name, age, phone, address, class_id) VALUES
    <foreach collection="list" separator="," item="item">
        (#{item.name},#{item.age},#{item.phone},#{item.address},#{item.classId})
    </foreach>
  </insert>
</mapper>

mapper接口：

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public interface StudentMapper {
    int insert(Student student);
 
    int insertBatch(List<Student> studentList);
}

测试代码：

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@SpringBootTest
class DemoApplicationTests {
    @Resource
    private StudentMapper studentMapper;
 
    @Test
    public void testInsertByForeachTag(){
        //数据生成
        List<Student> studentList = createData(100);
 
        //使用foreach标签，拼接SQL插入
        long start = System.currentTimeMillis();
        studentMapper.insertBatch(studentList);
        System.out.println(System.currentTimeMillis() - start);
    }
 
 
    private List<Student> createData(int size){
        List<Student> studentList = new ArrayList<>();
        Student student;
        for(int i = 0; i < size; i++){
            student = new Student();
            student.setName("小王" + i);
            student.setAge(18);
            student.setClassId(1);
            student.setPhone("1585xxxx669");
            student.setAddress("未知");
            studentList.add(student);
        }
 
        return studentList;
    }
}

 

 

3. 批处理

测试代码：

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@SpringBootTest
class DemoApplicationTests {
    @Autowired
    private SqlSessionFactory sqlSessionFactory;
 
    @Test
    public void testInsertBatch(){
        //数据生成
        List<Student> studentList = createData(100);
 
                //使用批处理
        long start = System.currentTimeMillis();
        SqlSession sqlSession = sqlSessionFactory.openSession(ExecutorType.BATCH,false);
        StudentMapper studentMapperNew = sqlSession.getMapper(StudentMapper.class);
        studentList.stream().forEach(student -> studentMapperNew.insert(student));
        sqlSession.commit();
        sqlSession.clearCache();
        System.out.println(System.currentTimeMillis() - start);
    }
 
    private List<Student> createData(int size){
        List<Student> studentList = new ArrayList<>();
        Student student;
        for(int i = 0; i < size; i++){
            student = new Student();
            student.setName("小王" + i);
            student.setAge(18);
            student.setClassId(1);
            student.setPhone("1585xxxx669");
            student.setAddress("未知");
            studentList.add(student);
        }
 
        return studentList;
    }
}

 

三种方式的对比

MySQL服务器版本：5.6.4

其他依赖版本如下：

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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.buhe</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
 
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
 
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.41</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>
    </dependencies>
 
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
 
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
    </build>
 
</project>

三种插入方式在不同数据量下的表现，测试结果：

 

插入方式10条100条500条1000条
循环插入 496ms 3330ms 15584ms 33755ms
foreach标签 268ms 366ms 392ms 684ms
批处理 222ms 244ms 364ms 426ms

 

三种方式中，批处理的方式效率是最高的，尤其是在数据量大的情况下尤为明显。

 

 

 

 

 

其次是foreach标签，foreach标签是通过拼接SQL语句的方式完成批量操作的。但是当拼接的SQL过多，导致SQL大小超过了MySQL服务器中max_allowed_packet变量的值时，会导致操作失败，抛出PacketTooBigException异常。

最后是循环插入的方式，这种方式在数据量小的时候可以使用，在数据量大的情况下效率要低很多。

 

___________________________________________________________

 

 

1. isnull(expr)

如果expr为null，则返回1，否则返回0

SELECT ISNULL(null) from dual; --结果为1

SELECT isnull(1/0) from dual; --结果为1

SELECT isnull(1/null) from dual; --结果为1

SELECT ISNULL(5) from dual; --结果为0

SELECT ISNULL('a') from dual; --结果为0

SELECT ISNULL(5+5) from dual; --结果为0

2. ifnull(expr1, expr2)

根isnull类似，expr1不为null的情况下，返回expr1，返回expr2

SELECT IFNULL(1,2) from dual; --1

SELECT IFNULL(null,2) from dual; --2

SELECT IFNULL(1/0,'can not be null') from dual; --'can not be null'

3. nullif(expr1, expr2)

nullif和ifnull完全不同，它表示如果两个表达式相同，则返回null，否则返回expr1的值

个人感觉应该叫null if equals

SELECT NULLIF(1,3) from dual; --1

SELECT NULLIF(3,3) from dual; --null

SELECT NULLIF(1+2,3) from dual; --null

4. coalesce(expr1, expr2,… exprN)

发音是core or less，英文的意思是联合/合并，在mysql中的用途是返回第一个不是null的值

SELECT COALESCE(null,1/0,2) from dual; --2

SELECT COALESCE(null,1/0,2,3) from dual; --2

只有两个参数的情况下，相当于ifnull

SELECT IFNULL(null,2) from dual; --2

SELECT COALESCE(null,2) from dual; --2
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posted @ 2022-10-18 16:57  kelelipeng  阅读(4602)  评论(0)    收藏  举报