Describe the bug
A clear and concise description of what the bug is.
优化类AbstractMapper的insert、update方法。合并insert方法的for循环，优化split操作，使用StringJoiner替代StringBuilder拼接
Expected behavior
A clear and concise description of what you expected to happen.
增强代码可读性、避免循环嵌套和冗余的判断条件
Actually behavior
A clear and concise description of what you actually to happen.

How to Reproduce
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1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See errors

Desktop (please complete the following information):

• OS: [e.g. Centos] windows
• Version [e.g. nacos-server 1.3.1, nacos-client 1.3.1] nacos-server 3.0.2
• Module [e.g. naming/config] plugin/datasource
• SDK [e.g. original, spring-cloud-alibaba-nacos, dubbo]

Additional context
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