分布式ID选型对比（2）

数据库号段模式

一, 引入���赖:

    mysql    mysql-connector-java    8.0.19    org.mybatis.spring.boot    mybatis-spring-boot-starter    2.2.2

二, 新建表

CREATE TABLE `id_generator` (  `id` int NOT NULL,  `max_id` bigint NOT NULL COMMENT '当前最大id',  `step` int NOT NULL COMMENT '号段的布长',  `biz_type` int NOT NULL COMMENT '业务类型',  `version` int NOT NULL COMMENT '版本号',  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

三, resources目录下编写自动生成代码配置文件: generatorConfig.xml

application.properties数据库配置:

#   ???urlspring.datasource.url=jdbc:mysql://localhost:3306/generate_id?characterEncoding=utf8&serverTimezone=UTC    #  ??????spring.datasource.username=root#  ?????spring.datasource.password=root#  ?????spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver###################################### MyBatis ??####################################### ?? mapper.xml ???mybatis.mapper-locations=classpath:mybatis/*.xml#????????,?????????????? mapper.xml ??????????????mybatis.type-aliases-package=net.biancheng.www.bean#???????????????????mybatis.configuration.map-underscore-to-camel-case=true

四, 编写层级代码

1, 对象 IdGenerator

package org.com.spi.model;public class IdGenerator {    private Integer id;    private Long maxId;    private Integer step;    private Integer bizType;    private Integer version;    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public Long getMaxId() {        return maxId;    }    public void setMaxId(Long maxId) {        this.maxId = maxId;    }    public Integer getStep() {        return step;    }    public void setStep(Integer step) {        this.step = step;    }    public Integer getBizType() {        return bizType;    }    public void setBizType(Integer bizType) {        this.bizType = bizType;    }    public Integer getVersion() {        return version;    }    public void setVersion(Integer version) {        this.version = version;    }}

IdGeneratorExample:

package org.com.spi.model;import java.util.ArrayList;import java.util.List;public class IdGeneratorExample {    protected String orderByClause;    protected boolean distinct;    protected List oredCriteria;    public IdGeneratorExample() {        oredCriteria = new ArrayList();    }    public void setOrderByClause(String orderByClause) {        this.orderByClause = orderByClause;    }    public String getOrderByClause() {        return orderByClause;    }    public void setDistinct(boolean distinct) {        this.distinct = distinct;    }    public boolean isDistinct() {        return distinct;    }    public List getOredCriteria() {        return oredCriteria;    }    public void or(Criteria criteria) {        oredCriteria.add(criteria);    }    public Criteria or() {        Criteria criteria = createCriteriaInternal();        oredCriteria.add(criteria);        return criteria;    }    public Criteria createCriteria() {        Criteria criteria = createCriteriaInternal();        if (oredCriteria.size() == 0) {            oredCriteria.add(criteria);        }        return criteria;    }    protected Criteria createCriteriaInternal() {        Criteria criteria = new Criteria();        return criteria;    }    public void clear() {        oredCriteria.clear();        orderByClause = null;        distinct = false;    }    protected abstract static class GeneratedCriteria {        protected List criteria;        protected GeneratedCriteria() {            super();            criteria = new ArrayList();        }        public boolean isValid() {            return criteria.size() > 0;        }        public List getAllCriteria() {            return criteria;        }        public List getCriteria() {            return criteria;        }        protected void addCriterion(String condition) {            if (condition == null) {                throw new RuntimeException("Value for condition cannot be null");            }            criteria.add(new Criterion(condition));        }        protected void addCriterion(String condition, Object value, String property) {            if (value == null) {                throw new RuntimeException("Value for " + property + " cannot be null");            }            criteria.add(new Criterion(condition, value));        }        protected void addCriterion(String condition, Object value1, Object value2, String property) {            if (value1 == null || value2 == null) {                throw new RuntimeException("Between values for " + property + " cannot be null");            }            criteria.add(new Criterion(condition, value1, value2));        }        public Criteria andIdIsNull() {            addCriterion("id is null");            return (Criteria) this;        }        public Criteria andIdIsNotNull() {            addCriterion("id is not null");            return (Criteria) this;        }        public Criteria andIdEqualTo(Integer value) {            addCriterion("id =", value, "id");            return (Criteria) this;        }        public Criteria andIdNotEqualTo(Integer value) {            addCriterion("id ", value, "id");            return (Criteria) this;        }        public Criteria andIdGreaterThan(Integer value) {            addCriterion("id >", value, "id");            return (Criteria) this;        }        public Criteria andIdGreaterThanOrEqualTo(Integer value) {            addCriterion("id >=", value, "id");            return (Criteria) this;        }        public Criteria andIdLessThan(Integer value) {            addCriterion("id ", value, "maxId");            return (Criteria) this;        }        public Criteria andMaxIdGreaterThanOrEqualTo(Long value) {            addCriterion("max_id >=", value, "maxId");            return (Criteria) this;        }        public Criteria andMaxIdLessThan(Long value) {            addCriterion("max_id ", value, "step");            return (Criteria) this;        }        public Criteria andStepGreaterThanOrEqualTo(Integer value) {            addCriterion("step >=", value, "step");            return (Criteria) this;        }        public Criteria andStepLessThan(Integer value) {            addCriterion("step ", value, "bizType");            return (Criteria) this;        }        public Criteria andBizTypeGreaterThanOrEqualTo(Integer value) {            addCriterion("biz_type >=", value, "bizType");            return (Criteria) this;        }        public Criteria andBizTypeLessThan(Integer value) {            addCriterion("biz_type ", value, "version");            return (Criteria) this;        }        public Criteria andVersionGreaterThanOrEqualTo(Integer value) {            addCriterion("version >=", value, "version");            return (Criteria) this;        }        public Criteria andVersionLessThan(Integer value) {            addCriterion("version