小编Gaë*_*l J的帖子

我是 Scala 环境的新手，并尝试使用“scalikejdbc”进行 SQL 集成来构建一个测试项目。这是我的 build.sbt，遵循http://scalikejdbc.org/documentation/playframework-support.html上的文档

name := """run"""
organization := "com.example"

version := "1.0-SNAPSHOT"

lazy val root = (project in file(".")).enablePlugins(PlayScala)

scalaVersion := "2.13.10"

libraryDependencies ++= Seq(
    guice,
  "org.scalatestplus.play" %% "scalatestplus-play" % "5.0.0" % Test,
  "com.h2database"  %  "h2"                           % "1.4.200", // your jdbc driver here
  "org.scalikejdbc" %% "scalikejdbc"                  % "4.0.0",
  "org.scalikejdbc" %% "scalikejdbc-config"           % "4.0.0",
  "org.scalikejdbc" %% "scalikejdbc-play-initializer" % "2.8.0-scalikejdbc-3.5",
  "com.typesafe.play" %% "play-ws" % "2.3.1"

)
dependencyOverrides += "org.fluentlenium" % "fluentlenium-core" % "0.10.3"

// Adds additional packages …

使用 Scala 2.13.10 的本地解释器我运行以下代码

scala> val it = Iterator("a", "number", "of", "words")
val it: Iterator[String] = <iterator>
scala> it.size
val res0: Int = 4
scala> it.next()
val res14: String = a

我假设运行命令 it.size 将遍历迭代器，并且 it.next() 将失败，正如 Scala 文档中所述

it.size 它返回的元素数量。注意：此操作结束！

https://docs.scala-lang.org/overviews/collections-2.13/iterators.html

我在这里缺少什么？

我是 scala 新手，我将一些代码从 scala 2.12 迁移到 13。我有以下代码

override def transformSchema(schema: StructType): StructType = {
    StructType(schema.fields ++ this.getOutputCols.map[StructField, Array[StructField]]( col => StructField(col, StringType)))
  }

我面临以下错误：

wrong number of type parameters for method map: [B](f: String => B)(implicit ct: scala.reflect.ClassTag[B]): Array[B]
[ERROR]     StructType(schema.fields ++ this.getOutputCols.map[StructField, Array[StructField]]( col => StructField(col, StringType)))

你能解释一下为什么scala 2.13有这个问题吗，我没有找到与文档相关的东西map方法尝试转换数组，应该没问题

我在java中创建一个简单的登录程序.这是我到目前为止的代码.

import java.util.Scanner;
import java.io.*;
import java.util.Arrays;

public class PasswordProgram {

    public static String user;
    public String password;
    public static boolean part1Finish = false;
    public File file = new File("D:/file.txt");
    public FileWriter UsernameWrite;
    public char[] user1;

    public void part1() {
        System.out.println("Please create an account: ");
        Scanner input = new Scanner(System. in );
        System.out.println("Type in a username: ");
        String user = input.next();

        System.out.println("Type in a Password: ");
        String password = input.next();
        try {
            UsernameWrite = new FileWriter(file);
            UsernameWrite.write(user);
            UsernameWrite.write(password);
            System.out.println(user);
            UsernameWrite.close(); …

package com.company;

import java.text.NumberFormat;
public class Main {

    public static void main(String[] args) {
        NumberFormat currency = NumberFormat.getCurrencyInstance();
        String result = currency.format(number: 1234837.343);
        System.out.println(result);
    }
}

第一种方法:

public void Calculate (int a, int b) {
    int sum =a+b;
}

第二种方法:

public int getResult(){
    return sum ;
}