The importance of parameter naming, remember a JDBC parameter conflict

Properties info = new Properties();
                info.setProperty("user", "root");
                info.setProperty("password", "850656");
                info.setProperty("agentID", "1001");
                info.setProperty("dbName", "mysql");
                
                // Load a custom driver
                Class.forName("com.fanruan.myJDBC.driver.MyDriver");
                Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test", info);
                Statement st = conn.createStatement();
                ResultSet rs = st.executeQuery("select * from `student`");
​
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如上,由于我重写了JDBC驱动,也就是上文的com.fanruan.myJDBC.driver.MyDriver.The effect of the rewrite is presumably passedRPC调用客户端的JDBC执行相应操作.由于RPCthe need to call,在DriverManager.getConnection(String url, Properties info)There are two more parameters encapsulated in the middle,agentID和dbName方便 Agent Distribute incoming call messages.测试运行时,It is displayed on the client as follows：

There are programs writtenbug我已经习惯了,但是令我费解的是,我明明在 urlThe database is indicated in test, Why is it wrongTable 'mysql.student' doesn't exist呢？

It is known that establishing a connection is ultimately calledconnect方法：

    public java.sql.Connection connect(String url, Properties info) throws SQLException {
        ...
    }
​
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mysql的JDBC实现中,会对传入的 Properties 参数进行解析

public ConnectionImpl(HostInfo hostInfo) throws SQLException {
    ...
        this.database = hostInfo.getDatabase();
    ...
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 public String getDatabase() {
     // 在 PropertyKey There is just one called dbname 的键
        String database = this.hostProperties.get(PropertyKey.DBNAME.getKeyName());
        return isNullOrEmpty(database) ? "" : database;
    }
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Cause would have been parsed as test的database：

被覆盖成了mysqlresulting in the error mentioned above.

可以看到进入getConnectionURLInstance时,dbName还是驼峰命名.

被处理为connectionURL之后就变成了dbname,This is also covered abovedatabase的前置条件.

至于为什么,That's because of parsingDBNAMEis set to be case insensitive：