怎么办这是Apifox里执行http://localhost:9002/goods/getByUserName？name=“张三“为什么我改了还是500？

{ "timestamp": "2025-10-02T11:27:53.384+0000", "status": 500, "error": "Internal Server Error", "message": "nested exception is org.apache.ibatis.exceptions.PersistenceException: \r\n### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure\n\nThe last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.\r\n### The error may exist in file [D:\SUM\代码\demo251001\target\classes\mapper\UserMapper.xml]\r\n### The error may involve com.daqin.demo251001.mapper.UserMapper.getByUserName\r\n### The error occurred while executing a query\r\n### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure\n\nThe last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.", "path": "/goods/getByUserName" }怎么办这是Apifox里执行http://localhost:9002/goods/getByUserName？

name="张三"为什么我改了还是500？

根据错误信息分析，这是一个数据库连接失败的问题，而不是之前的MyBatis映射问题。主要错误是：

```

Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

```

## 问题分析

这是一个典型的数据库连接通信失败错误，常见原因包括：

## 解决方案

1. **检查数据库服务状态**

   - 确认MySQL数据库服务是否正在运行

   - 检查数据库是否可以通过其他工具（如Navicat、MySQL Workbench）正常连接

2. **检查application.yml/application.properties配置**

   ```yaml

   spring:

     datasource:

       url: jdbc:mysql://localhost:3306/your_database_name

       username: your_username

       password: your_password

       driver-class-name: com.mysql.cj.jdbc.Driver

   ```

3. **检查数据库连接参数**

   - 确认数据库地址(`localhost`)、端口(`3306`)是否正确

   - 确认数据库名称是否存在

   - 确认用户名和密码是否正确

   - 检查是否需要添加时区参数: `?serverTimezone=UTC`

4. **检查网络连接**

   - 确认应用程序能够访问数据库服务器

   - 检查防火墙是否阻止了数据库端口

5. **检查MySQL驱动依赖**

   ```xml

   <dependency>

       <groupId>mysql</groupId>

       <artifactId>mysql-connector-java</artifactId>

   </dependency>

   ```

6. **增加连接池配置**

   ```yaml

   spring:

     datasource:

       hikari:

         connection-timeout: 20000

         maximum-pool-size: 10

         minimum-idle: 5

   ```

建议先检查数据库服务和连接配置是否正确。