java - 变量和字符串之间不兼容的操作数类型

Question

我遇到变量和字符串之间操作数类型不兼容的错误。这是我的代码片段。错误发生@ if ( handler == "CLOSE")

最重要的是，我是否正确连接了我的数据库？应该有一个“public void closeDB”，但是包含该语句时出现错误。

private DBHandler handler;
public void openDB() throws SQLException
    {
        // Open the DB Connection
        final String DBURL = "example";
        final String DBUSER = "example";
        final String DBPASS = "example";

        DriverManager.registerDriver(new oracle.jdbc.OracleDriver());
        Connection con = DriverManager.getConnection(DBURL, DBUSER, DBPASS);
        Statement statement = con.createStatement();
    }

    public void setFileName(String fileName)
    {
        this.fileName = fileName;
    }

    public void setMySQL( String mySQL )
    {
        this.mySQL = mySQL;
    }

    public ResultSet retrieveTheData(  ) throws SQLException
    {
        if ( handler == null )
        {
            // Create a new connection
        }

        if ( handler == "CLOSE" )
        {
            // Open the connection
        }

        // Message the Data 


        ResultSet rs;
        return rs;
    }

Answer 1

使用字符串的equals(Object anObject)适合您的工作:

"CLOSE".equals(handler.toString())