迁移polardb问题一

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环境

polardb版本

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<dependency>
  <groupId>com.aliyun</groupId>
  <artifactId>polardb-jdbc18</artifactId>
  <version>1.0.0</version>
  <scope>system</scope>
  <systemPath>${lib.dir}/polardb-jdbc18.jar</systemPath>
</dependency>

mybatis版本

直接使用springboot引入

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<dependency>
  <groupId>org.mybatis.spring.boot</groupId>
  <artifactId>mybatis-spring-boot-starter</artifactId>
  <version>2.1.4</version>
</dependency>

问题描述

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javax.servlet.ServletException: org.springframework.dao.DataIntegrityViolationException: 
### The error may exist in com/xx/templatedef/dao/oracle/XXTemplateDef_SqlMap.xml
### The error may involve com.xx.templatedef.dao.XXTemplateDefDao.selectTemplateDefByCategoryAndState-Inline
### The error occurred while setting parameters
### SQL: select * from act_xx_tem_def where category=? and deploy_state=1
### Cause: com.aliyun.polardb.util.PSQLException: 不良的类型值 long : 
com.aliyun.polardb.util.PSQLException: canot convert the column of type BYTEA to requested type long;

原因

mybatis查询act_tem_def表涉及到blob字段(content_bytes)，
默认的BlobTypeHandler的getBlob方法不适用, 需要重写handler

解决方案

  1. 在业务下重写BlobTypeHandler, 获取getBinaryStream然后转换byte数组
  2. mapper.xml -> resultmap中, 加入下述转换
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<result column="CONTENT_BYTES" property="contentBytes" jdbcType="BLOB"
  typeHandler="com.example.springbootpolardb.handler.PolarDbBlobTypeHandler"/>

转换逻辑

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public static byte[] toByteArray(InputStream input) throws IOException {
    ByteArrayOutputStream output = new ByteArrayOutputStream();
    byte[] buffer = new byte[4096];
    int n = 0;
    while (-1 != (n = input.read(buffer))) {
        output.write(buffer, 0, n);
    }
    return output.toByteArray();
}

代码