自定义MyBatis拦截器更改表名 - ToB企服应用市场:ToB评测及商务社交产业平台

package top.emanjusaka.springboottest.mybatis.plugin;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.reflection.DefaultReflectorFactory;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.SystemMetaObject;
import top.emanjusaka.springboottest.mybatis.annotation.DBTableStrategy;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* @Author emanjusaka
* @Date 2023/10/18 17:25
* @Version 1.0
*/
@Intercepts({@Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class})})
public class DynamicMybatisPlugin implements Interceptor {
private Pattern pattern = Pattern.compile("(from|into|update)[\\s]{1,}(\\w{1,})", Pattern.CASE_INSENSITIVE);
@Override
public Object intercept(Invocation invocation) throws Throwable {
StatementHandler statementHandler = (StatementHandler) invocation.getTarget();
MetaObject metaObject = MetaObject.forObject(statementHandler, SystemMetaObject.DEFAULT_OBJECT_FACTORY, SystemMetaObject.DEFAULT_OBJECT_WRAPPER_FACTORY, new DefaultReflectorFactory());
MappedStatement mappedStatement = (MappedStatement) metaObject.getValue("delegate.mappedStatement");
// 获取自定义注解判断是否进行分表操作
String id = mappedStatement.getId();
String className = id.substring(0, id.lastIndexOf("."));
Class<?> clazz = Class.forName(className);
DBTableStrategy dbTableStrategy = clazz.getAnnotation(DBTableStrategy.class);
if (null == dbTableStrategy || !dbTableStrategy.changeTable() || null == dbTableStrategy.tbIdx()) {
return invocation.proceed();
}
// 获取SQL
BoundSql boundSql = statementHandler.getBoundSql();
String sql = boundSql.getSql();
// 替换SQL表名
Matcher matcher = pattern.matcher(sql);
String tableName = null;
if (matcher.find()) {
tableName = matcher.group().trim();
}
assert null != tableName;
String replaceSql = matcher.replaceAll(tableName + "_" + dbTableStrategy.tbIdx());
// 通过反射修改SQL语句
Field field = boundSql.getClass().getDeclaredField("sql");
field.setAccessible(true);
field.set(boundSql, replaceSql);
field.setAccessible(false);
return invocation.proceed();
}
}

复制代码

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="top.emanjusaka.springboottest.score.repository.IScoreRepository">
<select id="selectAll" resultType="top.emanjusaka.springboottest.score.model.vo.ScoreVO">
select * from score
</select>
</mapper>

复制代码

package top.emanjusaka.springboottest.score.repository;
import org.apache.ibatis.annotations.Mapper;
import top.emanjusaka.springboottest.mybatis.annotation.DBTableStrategy;
import top.emanjusaka.springboottest.score.model.vo.ScoreVO;
import java.util.List;
/**
* @Author emanjusaka
* @Date 2023/10/18 17:45
* @Version 1.0
*/
@Mapper
@DBTableStrategy(changeTable = true,tbIdx = "2")
public interface IScoreRepository {
List<ScoreVO> selectAll();
}

复制代码

package top.emanjusaka.springboottest;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import top.emanjusaka.springboottest.score.model.vo.ScoreVO;
import top.emanjusaka.springboottest.score.service.IScore;
import javax.annotation.Resource;
import java.util.List;
@SpringBootTest
class SpringBootTestApplicationTests {
@Resource
private IScore score;
@Test
void contextLoads() {
List<ScoreVO> list = score.selectAll();
list.forEach(System.out::println);
}
}

复制代码