图片短链接生成器,网站优化 无需定金,网页制作与设计知识点复习,最近的新闻摘抄mybatis-plus 自动填充说明我们在设计表结构的时候,往往会额外添多如下几个字段create_time【表字段】-- createTime【实体字段】 #xff1a; 创建时间update_time【表字段】-- updateTime【实体字段】#xff1a;更新时间create_by【表字段】-- createBy 【实体字段】: 创建…mybatis-plus 自动填充说明我们在设计表结构的时候,往往会额外添多如下几个字段create_time【表字段】-- createTime【实体字段】 创建时间update_time【表字段】-- updateTime【实体字段】更新时间create_by【表字段】-- createBy 【实体字段】: 创建人update_by【表字段】--updateBy 【实体字段】更新人del_flag【表字段】-- delFlag【实体字段】 : 逻辑删除标识【0:未删除、1:已删除】在编写实体类【与数据映射】的时候不能总在每个类上都编写上述几个属性显得有些冗余于是我们将这几个属性提取出来并在对应的属性上标注mybatis-plus的填充注解那么所有继承BaseEntity的类将会拥有createTime,updateTime属性继承DefaultEntity的类将会拥有createTime、updateTime、createBy、updateBy、delFlag属性。至于为什么会设计两个类是因为有些中间表可能不需要用到createBy、updateBy、delFlag属性只需要createTime,updateTime属性。依赖引入com.baomidoumybatis-plus-boot-starter3.3.2org.projectlomboklombok1.18.12公用实体类定义package com.cloud.pango.common.core.entity;import com.baomidou.mybatisplus.annotation.FieldFill;import com.baomidou.mybatisplus.annotation.TableField;import lombok.Data;import lombok.EqualsAndHashCode;import lombok.ToString;import java.util.Date;DataToStringEqualsAndHashCodepublic class BaseEntity{TableField(fill FieldFill.INSERT)//插入时填充private Date createTime;TableField(fill FieldFill.INSERT_UPDATE)//插入货更新时填充private Date updateTime;}package com.cloud.pango.common.core.entity;import com.baomidou.mybatisplus.annotation.FieldFill;import com.baomidou.mybatisplus.annotation.TableField;import com.baomidou.mybatisplus.annotation.TableLogic;import lombok.Data;import lombok.EqualsAndHashCode;import lombok.ToString;DataToStringEqualsAndHashCodepublic class DefaultEntity extends BaseEntity{TableField(fill FieldFill.INSERT) //插入时填充private String createBy;TableField(fill FieldFill.INSERT_UPDATE)//插入或更新时填充private String updateBy;TableField(fill FieldFill.INSERT) //插入时填充TableLogic//逻辑删除private Integer delFlag;}自动填充处理package com.cloud.pango.common.mybatis;import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;import lombok.extern.slf4j.Slf4j;import org.apache.ibatis.reflection.MetaObject;import org.springframework.beans.factory.annotation.Autowired;import java.util.Date;Slf4jpublic class EntityMetaObjectHanlder implements MetaObjectHandler {private final static String CREATE_TIME createTime;private final static String UPDATE_TIME updateTime;private final static String CREATE_BY createBy;private final static String UPDATE_BY updateBy;private final static String DEL_FLAG delFlag;Autowiredprivate MetaObjectOperator metaObjectOperator;private void setMeta(MetaObject metaObject,String field,Object defaultValue){if(metaObject.hasGetter(field)){Object value metaObject.getValue(field);if(null ! value){this.setFieldValByName(field,value,metaObject);}else {this.setFieldValByName(field,defaultValue,metaObject);}}}private void setCreateTime(MetaObject metaObject){setMeta(metaObject,CREATE_TIME,new Date());}private void setUpdateTime(MetaObject metaObject){setMeta(metaObject,UPDATE_TIME,new Date());}private void setCreateBy(MetaObject metaObject){Object createBy metaObjectOperator.getCreateBy();if(null createBy){return ;}setMeta(metaObject,CREATE_BY,createBy);}private void setUpdateBy(MetaObject metaObject){Object updateBy metaObjectOperator.getUpdateBy();if(null updateBy){return ;}setMeta(metaObject,UPDATE_BY,updateBy);}private void setDelFlag(MetaObject metaObject){setMeta(metaObject,DEL_FLAG,0);}Overridepublic void insertFill(MetaObject metaObject) {String name metaObject.getOriginalObject().getClass().getName();if(log.isDebugEnabled()){log.debug({} 自动装配 createTime、updateTime、createBy、updateBy、delFlag,name);}setCreateTime(metaObject);setUpdateTime(metaObject);setCreateBy(metaObject);setUpdateBy(metaObject);setDelFlag(metaObject);}Overridepublic void updateFill(MetaObject metaObject) {String name metaObject.getOriginalObject().getClass().getName();if(log.isDebugEnabled()){log.debug({} 自动装配 updateTime、updateBy,name);}setUpdateTime(metaObject);setUpdateBy(metaObject);}}数据库读写分离在分布式纵横的年代人们想方设法提高应用程序的性能将数据库拆分为读写分离模式【主从复制】是一项提供性能的一种方案。当然这种方案只针对对数据一致性没那么高要求的程序【弱一致性】。因为在主数据库同步给从数据库时候有可能会出现一些额外情况如网络原因等导致主从数据库数据不一致。本案例采用动态数据源及mybatis-plus来实现读写分离引入依赖com.baomidoumybatis-plus-boot-starter3.3.2org.projectlomboklombok1.18.12com.baomidoudynamic-datasource-spring-boot-starter3.1.1配置application.yml文件配置名为master的主数据库【用于写操作】及名为slave的从数据库【读操作】spring:datasource:dynamic:druid: # 全局druid参数绝大部分值和默认保持一致。(现已支持的参数如下,不清楚含义不要乱设置)# 连接池的配置信息# 初始化大小最小最大initial-size: 5min-idle: 5maxActive: 20# 配置获取连接等待超时的时间maxWait: 60000# 配置间隔多久才进行一次检测检测需要关闭的空闲连接单位是毫秒timeBetweenEvictionRunsMillis: 60000# 配置一个连接在池中最小生存的时间单位是毫秒minEvictableIdleTimeMillis: 300000validationQuery: SELECT 1 FROM DUALtestWhileIdle: truetestOnBorrow: falsetestOnReturn: false# 打开PSCache并且指定每个连接上PSCache的大小poolPreparedStatements: truemaxPoolPreparedStatementPerConnectionSize: 20# 配置监控统计拦截的filters去掉后监控界面sql无法统计wall用于防火墙filters: stat,wall,slf4j# 通过connectProperties属性来打开mergeSql功能慢SQL记录connectionProperties: druid.stat.mergeSql\true;druid.stat.slowSqlMillis\5000datasource:master:url: ${MYSQL_URL:jdbc:mysql://localhost:3306/master?characterEncodingUTF-8useUnicodetrueuseSSLfalse}username: ${MYSQL_USER:root}password: ${MYSQL_PASS:123456}driver-class-name: com.mysql.cj.jdbc.Driverslave:url: ${MYSQL_URL:jdbc:mysql://localhost:3306/slave?characterEncodingUTF-8useUnicodetrueuseSSLfalse}username: ${MYSQL_USER:root}password: ${MYSQL_PASS:123456}driver-class-name: com.mysql.cj.jdbc.Driver程序使用读写分离显式使用只需在对应的方法上加上DS注解并指明对应的数据源即可package com.cloud.pango.uc.service.impl;import com.baomidou.dynamic.datasource.annotation.DS;import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;import com.cloud.pango.uc.demo.DemoEntity;import com.cloud.pango.uc.mapper.DemoMapper;import com.cloud.pango.uc.service.DemoService;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;Servicepublic class DemoServiceImpl extends ServiceImpl implements DemoService {DS(master)//标明使用master数据源Overridepublic Boolean insert(DemoEntity demo) {save(demo);return true;}DS(slave)//标明使用slave数据源Overridepublic DemoEntity findById(String id){DemoEntity demo getById(id);return demo;}}隐式使用在未使用注解时使用mybatis-plus拦截器将读请求转移到slave数据源处理将写请求转移到master数据源处理package com.cloud.pango.uc.common;import com.baomidou.dynamic.datasource.toolkit.DynamicDataSourceContextHolder;import lombok.extern.slf4j.Slf4j;import org.apache.commons.lang3.StringUtils;import org.apache.ibatis.executor.Executor;import org.apache.ibatis.mapping.MappedStatement;import org.apache.ibatis.mapping.SqlCommandType;import org.apache.ibatis.plugin.*;import org.apache.ibatis.session.ResultHandler;import org.apache.ibatis.session.RowBounds;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Component;import org.springframework.transaction.support.TransactionSynchronizationManager;import java.util.Properties;Intercepts({Signature(type Executor.class, method update, args {MappedStatement.class, Object.class }),Signature(type Executor.class, method query, args {MappedStatement.class, Object.class, RowBounds.class,ResultHandler.class }) })Slf4jComponentpublic class DynamicInterceptor implements Interceptor {private static final String MASTER master;private static final String SLAVE slave;Overridepublic Object intercept(Invocation invocation) throws Throwable {boolean synchronizationActive TransactionSynchronizationManager.isSynchronizationActive();if(!synchronizationActive) {Object[] objects invocation.getArgs();MappedStatement ms (MappedStatement) objects[0];String currentDataSource DynamicDataSourceContextHolder.peek();if(StringUtils.isEmpty(currentDataSource)){if(ms.getSqlCommandType().equals(SqlCommandType.SELECT)) {DynamicDataSourceContextHolder.push(SLAVE);}else{DynamicDataSourceContextHolder.push(MASTER);}Object proceed invocation.proceed();DynamicDataSourceContextHolder.clear();return proceed;}}return invocation.proceed();}Overridepublic Object plugin(Object target) {if (target instanceof Executor) {return Plugin.wrap(target, this);} else {return target;}}Overridepublic void setProperties(Properties properties) {}}
