mybatis批量插入10萬條數據的優化過程

在使用mybatis插入大量數據的時候,爲了提高效率,放棄循環插入,改爲批量插入,mapper如下:

package com.lcy.service.mapper;

import com.lcy.service.pojo.TestVO;
import org.apache.ibatis.annotations.Insert;

import java.util.List;

/**
 * 功能描述：
 *
 * @author liuchaoyong
 * @version 1.0
 * @date 2019-06-26 13:18
 */
public interface TestMapper {

    @Insert("<script>" +
            "insert into test (t1,t2,t3,t4,t5) values " +
            "<foreach collection='list' item='obj' separator=','>" +
            "(#{obj.t1},#{obj.t2},#{obj.t3},#{obj.t4},#{obj.t5})" +
            "</foreach>" +
            "</script>")
    Integer testBatchInsert(List<TestVO> list);

}

實體類:

package com.lcy.service.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * 功能描述：
 *
 * @author liuchaoyong
 * @version 1.0
 * @date 2019-06-26 13:20
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
public class TestVO {

    private String t1;

    private String t2;

    private String t3;

    private String t4;

    private String t5;

}

測試類如下:

import com.lcy.service.TestApplication;
import com.lcy.service.mapper.TestMapper;
import com.lcy.service.pojo.TestVO;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

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

/**
 * 功能描述：
 *
 * @author liuchaoyong
 * @version 1.0
 * @date 2019-05-17 16:42
 */
@SpringBootTest(classes = TestApplication.class)
@RunWith(SpringRunner.class)
public class TestDemo {

    @Autowired
    private TestMapper testMapper;

    @Test
    public void insert() {
        List<TestVO> list = new ArrayList<>();
        for (int i = 0; i < 200000; i++) {
            list.add(new TestVO(i + "," + i, i + "," + i, i + "," + i, i + "," + i, i + "," + i));
        }
        System.out.println(testMapper.testBatchInsert(list));
    }

}

爲了復現bug,我限制了JVM內存:

 執行測試類報錯如下:

java.lang.OutOfMemoryError: Java heap space

	at java.base/java.util.Arrays.copyOf(Arrays.java:3746)

可以看到,Arrays在申請內存的時候,導致棧內存溢出

改進方法,分批新增:

import com.lcy.service.TestApplication;
import com.lcy.service.mapper.TestMapper;
import com.lcy.service.pojo.TestVO;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.swing.*;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * 功能描述：
 *
 * @author liuchaoyong
 * @version 1.0
 * @date 2019-05-17 16:42
 */
@SpringBootTest(classes = TestApplication.class)
@RunWith(SpringRunner.class)
public class TestDemo {

    @Autowired
    private TestMapper testMapper;

    @Test
    public void insert() {
        List<TestVO> list = new ArrayList<>();
        for (int i = 0; i < 200000; i++) {
            list.add(new TestVO(i + "," + i, i + "," + i, i + "," + i, i + "," + i, i + "," + i));
        }
        int index = list.size() / 10000;
        for (int i=0;i< index;i++){
            //stream流表達式，skip表示跳過前i*10000條記錄，limit表示讀取當前流的前10000條記錄
            testMapper.testBatchInsert(list.stream().skip(i*10000).limit(10000).collect(Collectors.toList()));
        }
    }

}

還有一種方法是調高JVM內存,不過不建議使用,不僅喫內存,而且數據量過大會導致sql過長報錯