• 分布式ID选型对比（2）

    数据库号段模式

    一, 引入依赖:

    2.     mysql
    3.     mysql-connector-java
    4.     8.0.19
    7.     org.mybatis.spring.boot
    8.     mybatis-spring-boot-starter
    9.     2.2.2

    二, 新建表

    1. CREATE TABLE `id_generator` (
    2.   `id` int NOT NULL,
    3.   `max_id` bigint NOT NULL COMMENT '当前最大id',
    4.   `step` int NOT NULL COMMENT '号段的布长',
    5.   `biz_type` int NOT NULL COMMENT '业务类型',
    6.   `version` int NOT NULL COMMENT '版本号',
    7.   PRIMARY KEY (`id`)
    8. ) 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

    1. "1.0" encoding="UTF-8"?>
    3.         PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
    4.         "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
    5.  
    7.     
    8.     "/Users/lizhihao/.m2/repository/mysql/mysql-connector-java/8.0.19/mysql-connector-java-8.0.19.jar"/>
    9.  
    10.     "testTables" targetRuntime="MyBatis3">
    11.         
    12.             
    13.             "suppressAllComments" value="true"/>
    14.         
    15.  
    16.         
    17.         "com.mysql.cj.jdbc.Driver"
    18.                         connectionURL="jdbc:mysql://localhost:3306/generate_id" userId="root"
    19.                         password="root">
    20.         
    21.  
    22.         
    23.         
    24.             "forceBigDecimals" value="false"/>
    25.         
    26.  
    27.         
    28.         "org.com.spi.model" targetProject="src/main/java">
    29.             
    30.             "enableSubPackages" value="false"/>
    31.             
    32.             "trimStrings" value="true"/>
    33.         
    34.  
    35.         
    36.         "mybatis" targetProject="src/main/resources">
    37.             "enableSubPackages" value="false"/>
    38.         
    39.  
    40.         
    41.         "XMLMAPPER" targetPackage="org.com.spi.dao" targetProject="src/main/java">
    42.             "enableSubPackages" value="false"/>
    43.         
    44.         
    45.         "worker_node">
    47.

    application.properties数据库配置:

    1. #   ???url
    2. spring.datasource.url=jdbc:mysql://localhost:3306/generate_id?characterEncoding=utf8&serverTimezone=UTC    
    3. #  ??????
    4. spring.datasource.username=root
    5. #  ?????
    6. spring.datasource.password=root
    7. #  ?????
    8. spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    9. ###################################### MyBatis ??######################################
    10. # ?? mapper.xml ???
    11. mybatis.mapper-locations=classpath:mybatis/*.xml
    12. #????????,?????????????? mapper.xml ??????????????
    13. mybatis.type-aliases-package=net.biancheng.www.bean
    14. #???????????????????
    15. mybatis.configuration.map-underscore-to-camel-case=true

    四, 编写层级代码

    1, 对象 IdGenerator

    1. package org.com.spi.model;
    2.  
    3. public class IdGenerator {
    4.     private Integer id;
    5.  
    6.     private Long maxId;
    7.  
    8.     private Integer step;
    9.  
    10.     private Integer bizType;
    11.  
    12.     private Integer version;
    13.  
    14.     public Integer getId() {
    15.         return id;
    16.     }
    17.  
    18.     public void setId(Integer id) {
    19.         this.id = id;
    20.     }
    21.  
    22.     public Long getMaxId() {
    23.         return maxId;
    24.     }
    25.  
    26.     public void setMaxId(Long maxId) {
    27.         this.maxId = maxId;
    28.     }
    29.  
    30.     public Integer getStep() {
    31.         return step;
    32.     }
    33.  
    34.     public void setStep(Integer step) {
    35.         this.step = step;
    36.     }
    37.  
    38.     public Integer getBizType() {
    39.         return bizType;
    40.     }
    41.  
    42.     public void setBizType(Integer bizType) {
    43.         this.bizType = bizType;
    44.     }
    45.  
    46.     public Integer getVersion() {
    47.         return version;
    48.     }
    49.  
    50.     public void setVersion(Integer version) {
    51.         this.version = version;
    52.     }
    53. }

    IdGeneratorExample:

    1. package org.com.spi.model;
    2.  
    3. import java.util.ArrayList;
    4. import java.util.List;
    5.  
    6. public class IdGeneratorExample {
    7.     protected String orderByClause;
    8.  
    9.     protected boolean distinct;
    10.  
    11.     protected List oredCriteria;
    12.  
    13.     public IdGeneratorExample() {
    14.         oredCriteria = new ArrayList();
    15.     }
    16.  
    17.     public void setOrderByClause(String orderByClause) {
    18.         this.orderByClause = orderByClause;
    19.     }
    20.  
    21.     public String getOrderByClause() {
    22.         return orderByClause;
    23.     }
    24.  
    25.     public void setDistinct(boolean distinct) {
    26.         this.distinct = distinct;
    27.     }
    28.  
    29.     public boolean isDistinct() {
    30.         return distinct;
    31.     }
    32.  
    33.     public List getOredCriteria() {
    34.         return oredCriteria;
    35.     }
    36.  
    37.     public void or(Criteria criteria) {
    38.         oredCriteria.add(criteria);
    39.     }
    40.  
    41.     public Criteria or() {
    42.         Criteria criteria = createCriteriaInternal();
    43.         oredCriteria.add(criteria);
    44.         return criteria;
    45.     }
    46.  
    47.     public Criteria createCriteria() {
    48.         Criteria criteria = createCriteriaInternal();
    49.         if (oredCriteria.size() == 0) {
    50.             oredCriteria.add(criteria);
    51.         }
    52.         return criteria;
    53.     }
    54.  
    55.     protected Criteria createCriteriaInternal() {
    56.         Criteria criteria = new Criteria();
    57.         return criteria;
    58.     }
    59.  
    60.     public void clear() {
    61.         oredCriteria.clear();
    62.         orderByClause = null;
    63.         distinct = false;
    64.     }
    65.  
    66.     protected abstract static class GeneratedCriteria {
    67.         protected List criteria;
    68.  
    69.         protected GeneratedCriteria() {
    70.             super();
    71.             criteria = new ArrayList();
    72.         }
    73.  
    74.         public boolean isValid() {
    75.             return criteria.size() > 0;
    76.         }
    77.  
    78.         public List getAllCriteria() {
    79.             return criteria;
    80.         }
    81.  
    82.         public List getCriteria() {
    83.             return criteria;
    84.         }
    85.  
    86.         protected void addCriterion(String condition) {
    87.             if (condition == null) {
    88.                 throw new RuntimeException("Value for condition cannot be null");
    89.             }
    90.             criteria.add(new Criterion(condition));
    91.         }
    92.  
    93.         protected void addCriterion(String condition, Object value, String property) {
    94.             if (value == null) {
    95.                 throw new RuntimeException("Value for " + property + " cannot be null");
    96.             }
    97.             criteria.add(new Criterion(condition, value));
    98.         }
    99.  
    100.         protected void addCriterion(String condition, Object value1, Object value2, String property) {
    101.             if (value1 == null || value2 == null) {
    102.                 throw new RuntimeException("Between values for " + property + " cannot be null");
    103.             }
    104.             criteria.add(new Criterion(condition, value1, value2));
    105.         }
    106.  
    107.         public Criteria andIdIsNull() {
    108.             addCriterion("id is null");
    109.             return (Criteria) this;
    110.         }
    111.  
    112.         public Criteria andIdIsNotNull() {
    113.             addCriterion("id is not null");
    114.             return (Criteria) this;
    115.         }
    116.  
    117.         public Criteria andIdEqualTo(Integer value) {
    118.             addCriterion("id =", value, "id");
    119.             return (Criteria) this;
    120.         }
    121.  
    122.         public Criteria andIdNotEqualTo(Integer value) {
    123.             addCriterion("id <>", value, "id");
    124.             return (Criteria) this;
    125.         }
    126.  
    127.         public Criteria andIdGreaterThan(Integer value) {
    128.             addCriterion("id >", value, "id");
    129.             return (Criteria) this;
    130.         }
    131.  
    132.         public Criteria andIdGreaterThanOrEqualTo(Integer value) {
    133.             addCriterion("id >=", value, "id");
    134.             return (Criteria) this;
    135.         }
    136.  
    137.         public Criteria andIdLessThan(Integer value) {
    138.             addCriterion("id <", value, "id");
    139.             return (Criteria) this;
    140.         }
    141.  
    142.         public Criteria andIdLessThanOrEqualTo(Integer value) {
    143.             addCriterion("id <=", value, "id");
    144.             return (Criteria) this;
    145.         }
    146.  
    147.         public Criteria andIdIn(List values) {
    148.             addCriterion("id in", values, "id");
    149.             return (Criteria) this;
    150.         }
    151.  
    152.         public Criteria andIdNotIn(List values) {
    153.             addCriterion("id not in", values, "id");
    154.             return (Criteria) this;
    155.         }
    156.  
    157.         public Criteria andIdBetween(Integer value1, Integer value2) {
    158.             addCriterion("id between", value1, value2, "id");
    159.             return (Criteria) this;
    160.         }
    161.  
    162.         public Criteria andIdNotBetween(Integer value1, Integer value2) {
    163.             addCriterion("id not between", value1, value2, "id");
    164.             return (Criteria) this;
    165.         }
    166.  
    167.         public Criteria andMaxIdIsNull() {
    168.             addCriterion("max_id is null");
    169.             return (Criteria) this;
    170.         }
    171.  
    172.         public Criteria andMaxIdIsNotNull() {
    173.             addCriterion("max_id is not null");
    174.             return (Criteria) this;
    175.         }
    176.  
    177.         public Criteria andMaxIdEqualTo(Long value) {
    178.             addCriterion("max_id =", value, "maxId");
    179.             return (Criteria) this;
    180.         }
    181.  
    182.         public Criteria andMaxIdNotEqualTo(Long value) {
    183.             addCriterion("max_id <>", value, "maxId");
    184.             return (Criteria) this;
    185.         }
    186.  
    187.         public Criteria andMaxIdGreaterThan(Long value) {
    188.             addCriterion("max_id >", value, "maxId");
    189.             return (Criteria) this;
    190.         }
    191.  
    192.         public Criteria andMaxIdGreaterThanOrEqualTo(Long value) {
    193.             addCriterion("max_id >=", value, "maxId");
    194.             return (Criteria) this;
    195.         }
    196.  
    197.         public Criteria andMaxIdLessThan(Long value) {
    198.             addCriterion("max_id <", value, "maxId");
    199.             return (Criteria) this;
    200.         }
    201.  
    202.         public Criteria andMaxIdLessThanOrEqualTo(Long value) {
    203.             addCriterion("max_id <=", value, "maxId");
    204.             return (Criteria) this;
    205.         }
    206.  
    207.         public Criteria andMaxIdIn(List values) {
    208.             addCriterion("max_id in", values, "maxId");
    209.             return (Criteria) this;
    210.         }
    211.  
    212.         public Criteria andMaxIdNotIn(List values) {
    213.             addCriterion("max_id not in", values, "maxId");
    214.             return (Criteria) this;
    215.         }
    216.  
    217.         public Criteria andMaxIdBetween(Long value1, Long value2) {
    218.             addCriterion("max_id between", value1, value2, "maxId");
    219.             return (Criteria) this;
    220.         }
    221.  
    222.         public Criteria andMaxIdNotBetween(Long value1, Long value2) {
    223.             addCriterion("max_id not between", value1, value2, "maxId");
    224.             return (Criteria) this;
    225.         }
    226.  
    227.         public Criteria andStepIsNull() {
    228.             addCriterion("step is null");
    229.             return (Criteria) this;
    230.         }
    231.  
    232.         public Criteria andStepIsNotNull() {
    233.             addCriterion("step is not null");
    234.             return (Criteria) this;
    235.         }
    236.  
    237.         public Criteria andStepEqualTo(Integer value) {
    238.             addCriterion("step =", value, "step");
    239.             return (Criteria) this;
    240.         }
    241.  
    242.         public Criteria andStepNotEqualTo(Integer value) {
    243.             addCriterion("step <>", value, "step");
    244.             return (Criteria) this;
    245.         }
    246.  
    247.         public Criteria andStepGreaterThan(Integer value) {
    248.             addCriterion("step >", value, "step");
    249.             return (Criteria) this;
    250.         }
    251.  
    252.         public Criteria andStepGreaterThanOrEqualTo(Integer value) {
    253.             addCriterion("step >=", value, "step");
    254.             return (Criteria) this;
    255.         }
    256.  
    257.         public Criteria andStepLessThan(Integer value) {
    258.             addCriterion("step <", value, "step");
    259.             return (Criteria) this;
    260.         }
    261.  
    262.         public Criteria andStepLessThanOrEqualTo(Integer value) {
    263.             addCriterion("step <=", value, "step");
    264.             return (Criteria) this;
    265.         }
    266.  
    267.         public Criteria andStepIn(List values) {
    268.             addCriterion("step in", values, "step");
    269.             return (Criteria) this;
    270.         }
    271.  
    272.         public Criteria andStepNotIn(List values) {
    273.             addCriterion("step not in", values, "step");
    274.             return (Criteria) this;
    275.         }
    276.  
    277.         public Criteria andStepBetween(Integer value1, Integer value2) {
    278.             addCriterion("step between", value1, value2, "step");
    279.             return (Criteria) this;
    280.         }
    281.  
    282.         public Criteria andStepNotBetween(Integer value1, Integer value2) {
    283.             addCriterion("step not between", value1, value2, "step");
    284.             return (Criteria) this;
    285.         }
    286.  
    287.         public Criteria andBizTypeIsNull() {
    288.             addCriterion("biz_type is null");
    289.             return (Criteria) this;
    290.         }
    291.  
    292.         public Criteria andBizTypeIsNotNull() {
    293.             addCriterion("biz_type is not null");
    294.             return (Criteria) this;
    295.         }
    296.  
    297.         public Criteria andBizTypeEqualTo(Integer value) {
    298.             addCriterion("biz_type =", value, "bizType");
    299.             return (Criteria) this;
    300.         }
    301.  
    302.         public Criteria andBizTypeNotEqualTo(Integer value) {
    303.             addCriterion("biz_type <>", value, "bizType");
    304.             return (Criteria) this;
    305.         }
    306.  
    307.         public Criteria andBizTypeGreaterThan(Integer value) {
    308.             addCriterion("biz_type >", value, "bizType");
    309.             return (Criteria) this;
    310.         }
    311.  
    312.         public Criteria andBizTypeGreaterThanOrEqualTo(Integer value) {
    313.             addCriterion("biz_type >=", value, "bizType");
    314.             return (Criteria) this;
    315.         }
    316.  
    317.         public Criteria andBizTypeLessThan(Integer value) {
    318.             addCriterion("biz_type <", value, "bizType");
    319.             return (Criteria) this;
    320.         }
    321.  
    322.         public Criteria andBizTypeLessThanOrEqualTo(Integer value) {
    323.             addCriterion("biz_type <=", value, "bizType");
    324.             return (Criteria) this;
    325.         }
    326.  
    327.         public Criteria andBizTypeIn(List values) {
    328.             addCriterion("biz_type in", values, "bizType");
    329.             return (Criteria) this;
    330.         }
    331.  
    332.         public Criteria andBizTypeNotIn(List values) {
    333.             addCriterion("biz_type not in", values, "bizType");
    334.             return (Criteria) this;
    335.         }
    336.  
    337.         public Criteria andBizTypeBetween(Integer value1, Integer value2) {
    338.             addCriterion("biz_type between", value1, value2, "bizType");
    339.             return (Criteria) this;
    340.         }
    341.  
    342.         public Criteria andBizTypeNotBetween(Integer value1, Integer value2) {
    343.             addCriterion("biz_type not between", value1, value2, "bizType");
    344.             return (Criteria) this;
    345.         }
    346.  
    347.         public Criteria andVersionIsNull() {
    348.             addCriterion("version is null");
    349.             return (Criteria) this;
    350.         }
    351.  
    352.         public Criteria andVersionIsNotNull() {
    353.             addCriterion("version is not null");
    354.             return (Criteria) this;
    355.         }
    356.  
    357.         public Criteria andVersionEqualTo(Integer value) {
    358.             addCriterion("version =", value, "version");
    359.             return (Criteria) this;
    360.         }
    361.  
    362.         public Criteria andVersionNotEqualTo(Integer value) {
    363.             addCriterion("version <>", value, "version");
    364.             return (Criteria) this;
    365.         }
    366.  
    367.         public Criteria andVersionGreaterThan(Integer value) {
    368.             addCriterion("version >", value, "version");
    369.             return (Criteria) this;
    370.         }
    371.  
    372.         public Criteria andVersionGreaterThanOrEqualTo(Integer value) {
    373.             addCriterion("version >=", value, "version");
    374.             return (Criteria) this;
    375.         }
    376.  
    377.         public Criteria andVersionLessThan(Integer value) {
    378.             addCriterion("version <", value, "version");
    379.             return (Criteria) this;
    380.         }
    381.  
    382.         public Criteria andVersionLessThanOrEqualTo(Integer value) {
    383.             addCriterion("version <=", value, "version");
    384.             return (Criteria) this;
    385.         }
    386.  
    387.         public Criteria andVersionIn(List values) {
    388.             addCriterion("version in", values, "version");
    389.             return (Criteria) this;
    390.         }
    391.  
    392.         public Criteria andVersionNotIn(List values) {
    393.             addCriterion("version not in", values, "version");
    394.             return (Criteria) this;
    395.         }
    396.  
    397.         public Criteria andVersionBetween(Integer value1, Integer value2) {
    398.             addCriterion("version between", value1, value2, "version");
    399.             return (Criteria) this;
    400.         }
    401.  
    402.         public Criteria andVersionNotBetween(Integer value1, Integer value2) {
    403.             addCriterion("version not between", value1, value2, "version");
    404.             return (Criteria) this;
    405.         }
    406.     }
    407.  
    408.     public static class Criteria extends GeneratedCriteria {
    409.  
    410.         protected Criteria() {
    411.             super();
    412.         }
    413.     }
    414.  
    415.     public static class Criterion {
    416.         private String condition;
    417.  
    418.         private Object value;
    419.  
    420.         private Object secondValue;
    421.  
    422.         private boolean noValue;
    423.  
    424.         private boolean singleValue;
    425.  
    426.         private boolean betweenValue;
    427.  
    428.         private boolean listValue;
    429.  
    430.         private String typeHandler;
    431.  
    432.         public String getCondition() {
    433.             return condition;
    434.         }
    435.  
    436.         public Object getValue() {
    437.             return value;
    438.         }
    439.  
    440.         public Object getSecondValue() {
    441.             return secondValue;
    442.         }
    443.  
    444.         public boolean isNoValue() {
    445.             return noValue;
    446.         }
    447.  
    448.         public boolean isSingleValue() {
    449.             return singleValue;
    450.         }
    451.  
    452.         public boolean isBetweenValue() {
    453.             return betweenValue;
    454.         }
    455.  
    456.         public boolean isListValue() {
    457.             return listValue;
    458.         }
    459.  
    460.         public String getTypeHandler() {
    461.             return typeHandler;
    462.         }
    463.  
    464.         protected Criterion(String condition) {
    465.             super();
    466.             this.condition = condition;
    467.             this.typeHandler = null;
    468.             this.noValue = true;
    469.         }
    470.  
    471.         protected Criterion(String condition, Object value, String typeHandler) {
    472.             super();
    473.             this.condition = condition;
    474.             this.value = value;
    475.             this.typeHandler = typeHandler;
    476.             if (value instanceof List) {
    477.                 this.listValue = true;
    478.             } else {
    479.                 this.singleValue = true;
    480.             }
    481.         }
    482.  
    483.         protected Criterion(String condition, Object value) {
    484.             this(condition, value, null);
    485.         }
    486.  
    487.         protected Criterion(String condition, Object value, Object secondValue, String typeHandler) {
    488.             super();
    489.             this.condition = condition;
    490.             this.value = value;
    491.             this.secondValue = secondValue;
    492.             this.typeHandler = typeHandler;
    493.             this.betweenValue = true;
    494.         }
    495.  
    496.         protected Criterion(String condition, Object value, Object secondValue) {
    497.             this(condition, value, secondValue, null);
    498.         }
    499.     }
    500. }

    2, dao层接口: IdGeneratorMapper

    1. package org.com.spi.dao;
    2.  
    3. import java.util.List;
    4.  
    5. import org.apache.ibatis.annotations.Mapper;
    6. import org.apache.ibatis.annotations.Param;
    7. import org.com.spi.model.IdGenerator;
    8. import org.com.spi.model.IdGeneratorExample;
    9.  
    10. @Mapper
    11. public interface IdGeneratorMapper {
    12.     int countByExample(IdGeneratorExample example);
    13.  
    14.     int deleteByExample(IdGeneratorExample example);
    15.  
    16.     int deleteByPrimaryKey(Integer id);
    17.  
    18.     int insert(IdGenerator record);
    19.  
    20.     int insertSelective(IdGenerator record);
    21.  
    22.     List selectByExample(IdGeneratorExample example);
    23.  
    24.     IdGenerator selectByPrimaryKey(Integer id);
    25.  
    26.     int updateByExampleSelective(@Param("record") IdGenerator record, @Param("example") IdGeneratorExample example);
    27.  
    28.     int updateByExample(@Param("record") IdGenerator record, @Param("example") IdGeneratorExample example);
    29.  
    30.     int updateByPrimaryKeySelective(IdGenerator record);
    31.  
    32.     int updateByPrimaryKey(IdGenerator record);
    33.  
    34.     IdGenerator selectMaxId(int bizType);
    35.  
    36.     int updateMaxId(IdGenerator idGenerator);
    37. }

    3, controller层: GenerateIdController

    1. @Autowired
    2. IdGeneratorMapper idGeneratorMapper;
    3. @PutMapping("/save1")
    4. public int save1(@RequestBody AutoGenerate1 autoGenerate){
    5.     IdGenerator idGenerator = idGeneratorMapper.selectMaxId(BizTypeEnum.GENERATE_ONE.getType());
    6.     int count = 0;
    7.     if(idGenerator == null){
    8.         idGenerator = new IdGenerator();
    9.         idGenerator.setId(1);
    10.         idGenerator.setStep(4);
    11.         idGenerator.setVersion(1);
    12.         idGenerator.setMaxId(1L);
    13.         idGenerator.setBizType(BizTypeEnum.GENERATE_ONE.getType());
    14.         count = idGeneratorMapper.insertSelective(idGenerator);
    15.         autoGenerate.setId(1L);
    16.     }else{
    17.         Long currentId = idGenerator.getMaxId() + idGenerator.getStep();
    18.         autoGenerate.setId(currentId);
    19.         idGenerator.setMaxId(currentId);
    20.         count = idGeneratorMapper.updateMaxId(idGenerator);
    21.     }
    22.     if(count > 0){//id生成后才能算成功进行新增
    23.         return autoGenerateMapper1.insert(autoGenerate);
    24.     }
    25.     return 0;
    26. }

    4, resources/mybatis目录下建: IdGeneratorMapper.xml

    1. "1.0" encoding="UTF-8" ?>
    2. "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
    3. "org.com.spi.dao.IdGeneratorMapper" >
    4.   "BaseResultMap" type="org.com.spi.model.IdGenerator" >
    5.     "id" property="id" jdbcType="INTEGER" />
    6.     "max_id" property="maxId" jdbcType="BIGINT" />
    7.     "step" property="step" jdbcType="INTEGER" />
    8.     "biz_type" property="bizType" jdbcType="INTEGER" />
    9.     "version" property="version" jdbcType="INTEGER" />
    10.   
    11.   "Example_Where_Clause" >
    12.     
    13.       "oredCriteria" item="criteria" separator="or" >
    14.         <if test="criteria.valid" >
    15.           "(" suffix=")" prefixOverrides="and" >
    16.             "criteria.criteria" item="criterion" >
    17.               
    18.                 "criterion.noValue" >
    19.                   and ${criterion.condition}
    20.                 
    21.                 "criterion.singleValue" >
    22.                   and ${criterion.condition} #{criterion.value}
    23.                 
    24.                 "criterion.betweenValue" >
    25.                   and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
    26.                 
    27.                 "criterion.listValue" >
    28.                   and ${criterion.condition}
    29.                   "criterion.value" item="listItem" open="(" close=")" separator="," >
    30.                     #{listItem}
    31.                   
    32.                 
    33.               
    34.             
    35.           
    36.         if>
    37.       
    38.     
    39.   
    40.   "Update_By_Example_Where_Clause" >
    41.     
    42.       "example.oredCriteria" item="criteria" separator="or" >
    43.         <if test="criteria.valid" >
    44.           "(" suffix=")" prefixOverrides="and" >
    45.             "criteria.criteria" item="criterion" >
    46.               
    47.                 "criterion.noValue" >
    48.                   and ${criterion.condition}
    49.                 
    50.                 "criterion.singleValue" >
    51.                   and ${criterion.condition} #{criterion.value}
    52.                 
    53.                 "criterion.betweenValue" >
    54.                   and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
    55.                 
    56.                 "criterion.listValue" >
    57.                   and ${criterion.condition}
    58.                   "criterion.value" item="listItem" open="(" close=")" separator="," >
    59.                     #{listItem}
    60.                   
    61.                 
    62.               
    63.             
    64.           
    65.         if>
    66.       
    67.     
    68.   
    69.   "Base_Column_List" >
    70.     id, max_id, step, biz_type, version
    71.   
    72.   
    73.   
    74.   
    75.   "deleteByPrimaryKey" parameterType="java.lang.Integer" >
    76.     delete from id_generator
    77.     where id = #{id,jdbcType=INTEGER}
    78.   
    79.   "deleteByExample" parameterType="org.com.spi.model.IdGeneratorExample" >
    80.     delete from id_generator
    81.     <if test="_parameter != null" >
    82.       "Example_Where_Clause" />
    83.     if>
    84.   
    85.   "insert" parameterType="org.com.spi.model.IdGenerator" >
    86.     insert into id_generator (id, max_id, step, 
    87.       biz_type, version)
    88.     values (#{id,jdbcType=INTEGER}, #{maxId,jdbcType=BIGINT}, #{step,jdbcType=INTEGER}, 
    89.       #{bizType,jdbcType=INTEGER}, #{version,jdbcType=INTEGER})
    90.   
    91.   "insertSelective" parameterType="org.com.spi.model.IdGenerator" >
    92.     insert into id_generator
    93.     "(" suffix=")" suffixOverrides="," >
    94.       <if test="id != null" >
    95.         id,
    96.       if>
    97.       <if test="maxId != null" >
    98.         max_id,
    99.       if>
    100.       <if test="step != null" >
    101.         step,
    102.       if>
    103.       <if test="bizType != null" >
    104.         biz_type,
    105.       if>
    106.       <if test="version != null" >
    107.         version,
    108.       if>
    109.     
    110.     "values (" suffix=")" suffixOverrides="," >
    111.       <if test="id != null" >
    112.         #{id,jdbcType=INTEGER},
    113.       if>
    114.       <if test="maxId != null" >
    115.         #{maxId,jdbcType=BIGINT},
    116.       if>
    117.       <if test="step != null" >
    118.         #{step,jdbcType=INTEGER},
    119.       if>
    120.       <if test="bizType != null" >
    121.         #{bizType,jdbcType=INTEGER},
    122.       if>
    123.       <if test="version != null" >
    124.         #{version,jdbcType=INTEGER},
    125.       if>
    126.     
    127.   
    128.   
    129.   "updateByExampleSelective" parameterType="map" >
    130.     update id_generator
    131.     
    132.       <if test="record.id != null" >
    133.         id = #{record.id,jdbcType=INTEGER},
    134.       if>
    135.       <if test="record.maxId != null" >
    136.         max_id = #{record.maxId,jdbcType=BIGINT},
    137.       if>
    138.       <if test="record.step != null" >
    139.         step = #{record.step,jdbcType=INTEGER},
    140.       if>
    141.       <if test="record.bizType != null" >
    142.         biz_type = #{record.bizType,jdbcType=INTEGER},
    143.       if>
    144.       <if test="record.version != null" >
    145.         version = #{record.version,jdbcType=INTEGER},
    146.       if>
    147.     
    148.     <if test="_parameter != null" >
    149.       "Update_By_Example_Where_Clause" />
    150.     if>
    151.   
    152.   "updateByExample" parameterType="map" >
    153.     update id_generator
    154.     set id = #{record.id,jdbcType=INTEGER},
    155.       max_id = #{record.maxId,jdbcType=BIGINT},
    156.       step = #{record.step,jdbcType=INTEGER},
    157.       biz_type = #{record.bizType,jdbcType=INTEGER},
    158.       version = #{record.version,jdbcType=INTEGER}
    159.     <if test="_parameter != null" >
    160.       "Update_By_Example_Where_Clause" />
    161.     if>
    162.   
    163.   "updateMaxId" parameterType="org.com.spi.model.IdGenerator" >
    164.     update id_generator set max_id = #{maxId},version = version + 1
    165.     where biz_type = #{bizType} and version = #{version}
    166.   
    167.   "updateByPrimaryKeySelective" parameterType="org.com.spi.model.IdGenerator" >
    168.     update id_generator
    169.     
    170.       <if test="maxId != null" >
    171.         max_id = #{maxId,jdbcType=BIGINT},
    172.       if>
    173.       <if test="step != null" >
    174.         step = #{step,jdbcType=INTEGER},
    175.       if>
    176.       <if test="bizType != null" >
    177.         biz_type = #{bizType,jdbcType=INTEGER},
    178.       if>
    179.       <if test="version != null" >
    180.         version = #{version,jdbcType=INTEGER},
    181.       if>
    182.     
    183.     where id = #{id,jdbcType=INTEGER}
    184.   
    185.   "updateByPrimaryKey" parameterType="org.com.spi.model.IdGenerator" >
    186.     update id_generator
    187.     set max_id = #{maxId,jdbcType=BIGINT},
    188.       step = #{step,jdbcType=INTEGER},
    189.       biz_type = #{bizType,jdbcType=INTEGER},
    190.       version = #{version,jdbcType=INTEGER}
    191.     where id = #{id,jdbcType=INTEGER}
    192.

    特点: 相较于数据库自增,扩展性更好,但缺点是每次取ID都需要加锁,性能较低.

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  • 原文地址：https://blog.csdn.net/qq_35255384/article/details/136415505