java mybatis mysql快速抽取全量数据

偏执的太偏执、 2023-02-18 01:52 22阅读 0赞

Java代码

import tk.mybatis.mapper.entity.Example;
    private void handleByBatch() {         List<String> personIdPreList = personInfoMapper.getPersonIdPreList();        personIdPreList = personIdPreList.stream().distinct().sorted().collect(Collectors.toList());        if (CollectionUtils.isEmpty(personIdPreList)) {             return;        }        Iterator<String> iterator = personIdPreList.iterator();        String beginIdPre = iterator.next();        while (iterator.hasNext()) {             String endIdPre = iterator.next();            handlePreIdData(beginIdPre, endIdPre);            beginIdPre = endIdPre;        }    }    
    private void handlePreIdData(String beginIdPre, String endIdPre) {         Example example = new Example(javaBean.class);//javaBean为实体类 Example.Criteria criteria = example.createCriteria(); criteria.andGreaterThanOrEqualTo("id", beginIdPre); criteria.andLessThan("id", endIdPre); List<javaBean> list = personInfoMapper.selectByExample(example); handleByPersonInfo(list); }

Javabean

import javax.persistence.Column; import javax.persistence.Id; import javax.persistence.Table; @Table(name = "tb_test") public class javaBean {  @Id private String id; @Column(name = "name") private String name; public String getId() {  return id; } public void setId(String id) {  this.id = id; } public String getName() {  return name; } public void setName(String name) {  this.name = name; } }

xml

<select id="getPersonIdPreList" resultType="java.lang.String"> select DISTINCT(left(id,3)) pre from tb_person_info </select>

**思路，取ID前三位，我做的时候500多万数据，分成了4000多，查的很快**