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本篇文章為大家展示了mybatis plus中怎么自定義主鍵生成器IKeyGenerator,內(nèi)容簡(jiǎn)明扼要并且容易理解,絕對(duì)能使你眼前一亮,通過(guò)這篇文章的詳細(xì)介紹希望你能有所收獲。
1. 繼承IKeyGenerator
@Slf4j @Component public class MybatisKeyGenerator implements IKeyGenerator { @Value("${server.worker-id}") private Integer workerId; @Value("${server.data-center-id}") private Integer dataCenterId; @Override public String executeSql(String incrementerName) { log.info("mybatis plus keyGenerator: " + incrementerName + "(" + workerId + "," + dataCenterId + ")"); long uid = new SnowflakeIdWorker(workerId, dataCenterId).nextId(); return "select " + uid + " from dual"; } }
2. 定義entity, 需要有@KeySequence注解,和IdType.INPUT或者IdType.ID_WORKER
@Data @TableName("test1") @KeySequence("mybatisKeyGenerator") public class Test { @TableId(type = IdType.INPUT) private Long id; private String name; }
3.測(cè)試:
@Autowired private TestMapper testMapper; @Override public void run(String... args) throws Exception { Test test = new Test(); test.setName("CCC"+ LocalDateTime.now()); testMapper.insert(test); System.out.println(">>>> test:"+ test); }
源碼查看:
1. com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration
// 從spring容器中獲取IKeyGenerator //注入主鍵生成器 if (this.applicationContext.getBeanNamesForType(IKeyGenerator.class, false, false).length > 0) { IKeyGenerator keyGenerator = this.applicationContext.getBean(IKeyGenerator.class); globalConfig.getDbConfig().setKeyGenerator(keyGenerator); }
2. 在掃描實(shí)體時(shí)候,會(huì)掃描KeySequence注解
/* 開啟了自定義 KEY 生成器 */ if (null != dbConfig.getKeyGenerator()) { tableInfo.setKeySequence(clazz.getAnnotation(KeySequence.class)); }
3. 插入數(shù)據(jù)時(shí):com.baomidou.mybatisplus.core.injector.methods.Insert
// 表包含主鍵處理邏輯,如果不包含主鍵當(dāng)普通字段處理 if (StringUtils.isNotEmpty(tableInfo.getKeyProperty())) { if (tableInfo.getIdType() == IdType.AUTO) { /** 自增主鍵 */ keyGenerator = new Jdbc3KeyGenerator(); keyProperty = tableInfo.getKeyProperty(); keyColumn = tableInfo.getKeyColumn(); } else { // 如果有注解,則獲取自定義的主鍵生成器 if (null != tableInfo.getKeySequence()) { // 這里獲取的就是注入的生成器,執(zhí)行生成器接口executeSql,傳入值為注解里面的value keyGenerator = TableInfoHelper.genKeyGenerator(tableInfo, builderAssistant, sqlMethod.getMethod(), languageDriver); keyProperty = tableInfo.getKeyProperty(); keyColumn = tableInfo.getKeyColumn(); } } }
4.
/** * <p> * 自定義 KEY 生成器 * </p> */ public static KeyGenerator genKeyGenerator(TableInfo tableInfo, MapperBuilderAssistant builderAssistant, String baseStatementId, LanguageDriver languageDriver) { IKeyGenerator keyGenerator = GlobalConfigUtils.getKeyGenerator(builderAssistant.getConfiguration()); if (null == keyGenerator) { throw new IllegalArgumentException("not configure IKeyGenerator implementation class."); } String id = baseStatementId + SelectKeyGenerator.SELECT_KEY_SUFFIX; Class<?> resultTypeClass = tableInfo.getKeySequence().clazz(); StatementType statementType = StatementType.PREPARED; String keyProperty = tableInfo.getKeyProperty(); String keyColumn = tableInfo.getKeyColumn(); // 執(zhí)行語(yǔ)句keyGenerator.executeSql(tableInfo.getKeySequence().value()) SqlSource sqlSource = languageDriver.createSqlSource(builderAssistant.getConfiguration(), keyGenerator.executeSql(tableInfo.getKeySequence().value()), null); builderAssistant.addMappedStatement(id, sqlSource, statementType, SqlCommandType.SELECT, null, null, null, null, null, resultTypeClass, null, false, false, false, new NoKeyGenerator(), keyProperty, keyColumn, null, languageDriver, null); id = builderAssistant.applyCurrentNamespace(id, false); MappedStatement keyStatement = builderAssistant.getConfiguration().getMappedStatement(id, false); SelectKeyGenerator selectKeyGenerator = new SelectKeyGenerator(keyStatement, true); builderAssistant.getConfiguration().addKeyGenerator(id, selectKeyGenerator); return selectKeyGenerator; }
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