将Postgres连接到Android Studio的问题

Question

最近几天我一直在处理一些代码，用于将PostgreSQL连接到Android Studio。我用oneClickListener做了一个按钮，单击后应该进行查询。但是，当我运行该程序时，出现一些错误，我无法弄清楚为什么，我确实安装了Postgresql驱动程序并将其放入。另外，如果您已成功将Postgres连接到Android Studio，您如何做到这一点？

public static void test（）{

}

/* This method return java.sql.Connection object. */
@SuppressWarnings("finally")
public String getPostgreSQLConnection()
{
    /* Declare and initialize a sql Connection variable. */
    Connection ret = null;
    String output = "";


    try
    {

        /* Register jdbc driver class. */
        Class.forName("org.postgresql.Driver");

        /* Create connection url. */
        String mysqlConnUrl = "jdbc:postgresql://localhost/Student";

        /* user name. */
        String mysqlUserName = "postgres";

        /* password. */
        String mysqlPassword = "asd";

        /* Get the Connection object. */
        ret = DriverManager.getConnection(mysqlConnUrl, mysqlUserName , mysqlPassword);

        /* Get related meta data for this mysql server to verify db connect successfully.. */
        DatabaseMetaData dbmd = ret.getMetaData();

        String dbName = dbmd.getDatabaseProductName();

        String dbVersion = dbmd.getDatabaseProductVersion();

        String dbUrl = dbmd.getURL();

        String userName = dbmd.getUserName();

        String driverName = dbmd.getDriverName();

        //STEP 4: Execute a query
        System.out.println("Creating statement...");
        java.sql.Statement st = null;
        st = ret.createStatement();
        String sql;
        sql = "INSERT INTO \"UserAccount\".\"UserInfo\"(\n" +
                "\t\"UserName\", \"Password\", \"ID\")\n" +
                "\tVALUES ('ss', 'string', 7)";
        //sql = "SELECT * FROM \"UserAccount\".\"UserInfo\"";
        ResultSet rs = st.executeQuery(sql);

        //STEP 5: Extract data from result set
        while(rs.next()){
            //Retrieve by column name
            String first = rs.getString("UserName");
            String last = rs.getString("Password");

            //Display values
            output.concat(first + last);
            System.out.print(", First: " + first);
            System.out.println(", Last: " + last);
        }
        //STEP 6: Clean-up environment
        rs.close();
        st.close();
        ret.close();

    }catch(Exception ex)
    {
        ex.printStackTrace();
    }finally
    {
        return output;
    }

}

} Here is the errors that i'm getting