配置Mybatis-config报错：Cannot load connection class because of underlying exception: com.mysql.cj.exceptions.WrongArgumentException: failed to parse the connection string near ';useUnicode=true&

参考：

配置MyBatis错误Cannot load connection class because of underlying exception: com.mysql.cj.exceptions..

常用转义字符例如&的含义

 

情况：

想将resource里面的db.properties数据传到Mybatis-config，运行UserDaoTest出错

db.properties：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT
username=root
password=123456

Mybatis-config.xml

<?xml version="1.0" encoding="utf8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
    <properties resource="db.properties" />

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>


    <mappers>
        <mapper resource="com/kuang/dao/UserMapper.xml"/>
    </mappers>
</configuration>

 

出错表现为：

org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.sql.SQLNonTransientConnectionException: Cannot load connection class because of underlying exception: com.mysql.cj.exceptions.WrongArgumentException: Malformed database URL, failed to parse the connection string near ';useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT'.
### The error may exist in com/kuang/dao/UserMapper.xml
### The error may involve com.kuang.dao.UserMapper.getUserLike
### The error occurred while executing a query
### Cause: java.sql.SQLNonTransientConnectionException: Cannot load connection class because of underlying exception: com.mysql.cj.exceptions.WrongArgumentException: Malformed database URL, failed to parse the connection string near ';useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT'.

 

根据出错信息，定位到db.properties文件，百度到下面的链接：

配置MyBatis错误Cannot load connection class because of underlying exception: com.mysql.cj.exceptions..

将mybatis中xml文件的properties标签内容转到另外一个外部配置文件jdbcCondig.properties中报错

我意识到应该是.properties文件和.xml数据库连接的url部分中的&&的解读方式不一样，在.xml文件中&&应该被写成&
而在.properties中应该是&&,所以我把.xml文件的url中的&改为&&后成功运行。

修改为：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis?useSSL=true&&useUnicode=true&&characterEncoding=UTF-8&&serverTimezone=GMT
username=root
password=123456

得以解决。