java - Scala:从 Java 到 Scala，如何消除 setter 和 getter 并减少代码大小

Question

更新:根据一位专家的建议，我清理了以下 Java 代码:有一个名为 MyRespModifier 的类，它包含两个名为 ResponseMail 和 Response 的内部静态类我重写了这段 Scala 代码作为练习。 Scala 版本:2.11.2。我对结果不满意。它类似于 Java，并且看起来可以从头开始使用大量惯用的 Scala。我希望减少行数，并且在检查代码时，它应该作为优雅的 Scala 代码脱颖而出。至少我的目标是了解如何用惯用的 Scala 重写一些 Java 结构。

Scala 等效项发布在 Java 代码之后:

import java.util.ArrayList;
import java.io.ByteArrayInputStream;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.io.FileInputStream;

import java.io.File;
import java.io.InputStream;
import java.io.IOException;
import org.apache.http.HttpResponse;
import org.apache.http.HttpEntity;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.util.EntityUtils;
import org.apache.http.entity.ContentType;

public class MyRespModifier {

private static final String VERSION           = "1.0.0";
private static final String USER_AGENT  = "myuseragent/"+ VERSION + "java";
private static final String ARG_TO          = "to[%d]";
private static final String ARG_TONAME      = "toname[%d]";
private static final String ARG_CC          = "cc[%d]";
private static final String ARG_FROM        = "from";
private static final String ARG_FROMNAME    = "fromname";
private static final String ARG_REPLYTO     = "replyto";
private static final String ARG_SUBJECT     = "subject";
private static final String ARG_CONTENTS    = "content[%s]";
private static final String ARG_MYSMTPAPI    = "x-respModifierSmtpApi";

private String apikey;
private String apivalue;
private String apiUrlBasePath;
private String port;
private String endpoint;
private CloseableHttpClient client;

  public MyRespModifier() {
      this.apiUrlBasePath = "api/responseshaper/response";
      this.endpoint = "/myapi/mymail.dispatch.json";
      this.client = HttpClientBuilder.create().setUserAgent(USER_AGENT).build();
  }

  public MyRespModifier setUrl(String url) {
    this.apiUrlBasePath = apiUrlBasePath;
    return this;
  }

  public MyRespModifier setEndpoint(String endpoint) {
    this.endpoint = endpoint;
    return this;
  }


  public MyRespModifier setClient(CloseableHttpClient client) {
    this.client = client;
    return this;
  }



public HttpEntity constructRespBody(ResponseEmail respEmail) {
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();

        builder.addTextBody("api_user", this.apikey);
        builder.addTextBody("api_key", this.apivalue);

        String[] tos = respEmail.getTos();
        String[] tonames = respEmail.getToNames();
        String[] ccs = respEmail.getCcs();

        if (tos.length == 0) {
          builder.addTextBody(String.format(ARG_TO, 0), respEmail.getFrom(), ContentType.create("text/plain", "UTF-8"));
        }
        for (int i = 0, len = tos.length; i < len; i++)
          builder.addTextBody(String.format(ARG_TO, i), tos[i], ContentType.create("text/plain", "UTF-8"));

        for (int i = 0, len = tonames.length; i < len; i++)
          builder.addTextBody(String.format(ARG_TONAME, i), tonames[i], ContentType.create("text/plain", "UTF-8"));

        for (int i = 0, len = ccs.length; i < len; i++)
          builder.addTextBody(String.format(ARG_CC, i), ccs[i], ContentType.create("text/plain", "UTF-8"));

        if (respEmail.getContentIds().size() > 0) {
          Iterator it = respEmail.getContentIds().entrySet().iterator();
          while (it.hasNext()) {
                Map.Entry entry = (Map.Entry) it.next();
                builder.addTextBody(String.format(ARG_CONTENTS, entry.getKey()), (String) entry.getValue());
            }
        }

            if (respEmail.getFrom() != null && !respEmail.getFrom().isEmpty())
              builder.addTextBody(ARG_FROM, respEmail.getFrom(), ContentType.create("text/plain", "UTF-8"));

            if (respEmail.getFromName() != null && !respEmail.getFromName().isEmpty())
              builder.addTextBody(ARG_FROMNAME, respEmail.getFromName(), ContentType.create("text/plain", "UTF-8"));

            if (respEmail.getReplyTo() != null && !respEmail.getReplyTo().isEmpty())
              builder.addTextBody(ARG_REPLYTO, respEmail.getReplyTo(), ContentType.create("text/plain", "UTF-8"));

            if (respEmail.getSubject() != null && !respEmail.getSubject().isEmpty())
              builder.addTextBody(ARG_SUBJECT, respEmail.getSubject(), ContentType.create("text/plain", "UTF-8"));

            String tmpString = respEmail.respModifierSmtpApi.jsonString();
            if (!tmpString.equals("{}"))
              builder.addTextBody(ARG_MYSMTPAPI, tmpString, ContentType.create("text/plain", "UTF-8"));

            return builder.build();
  } //end of method constructRespBody

  public MyRespModifier.Response send(ResponseEmail respMail) throws RespModifierException {
    HttpPost httppost = new HttpPost(this.apiUrlBasePath + this.endpoint);
    httppost.setEntity(this.constructRespBody(respMail));
    try {
      HttpResponse res = this.client.execute(httppost);
      return new MyRespModifier.Response(res.getStatusLine().getStatusCode(), EntityUtils.toString(res.getEntity()));
    } catch (IOException e) {
      throw new RespModifierException(e);
    }

  }

  //*********************************************************************

  public static class ResponseEmail {
    private MyExperimentalApi respModifierSmtpApi;
    private ArrayList<String> to;
    private ArrayList<String> toname;
    private ArrayList<String> cc;
    private String from;
    private String fromname;
    private String replyto;
    private String subject;
    private String text;
    private Map<String, String> contents;
    private Map<String, String> headers;

    public ResponseEmail () {
      this.respModifierSmtpApi = new MyExperimentalApi();
      this.to = new ArrayList<String>();
      this.toname = new ArrayList<String>();
      this.cc = new ArrayList<String>();
      this.contents = new HashMap<String, String>();
      this.headers = new HashMap<String, String>();
    }
public ResponseEmail addTo(String to) {
  this.to.add(to);
  return this;
}

public ResponseEmail addTo(String[] tos) {
  this.to.addAll(Arrays.asList(tos));
  return this;
}

public ResponseEmail addTo(String to, String name) {
  this.addTo(to);
  return this.addToName(name);
}

public ResponseEmail setTo(String[] tos) {
  this.to = new ArrayList<String>(Arrays.asList(tos));
  return this;
}

public String[] getTos() {
  return this.to.toArray(new String[this.to.size()]);
}

public ResponseEmail addSmtpApiTo(String to) {
  this.respModifierSmtpApi.addTo(to);
  return this;
}

public ResponseEmail addSmtpApiTo(String[] to) {
  this.respModifierSmtpApi.addTos(to);
  return this;
}



public ResponseEmail addToName(String toname) {
      this.toname.add(toname);
      return this;
    }

public ResponseEmail addToName(String[] tonames) {
  this.toname.addAll(Arrays.asList(tonames));
  return this;
}

public ResponseEmail setToName(String[] tonames) {
  this.toname = new ArrayList<String>(Arrays.asList(tonames));
  return this;
}

public String[] getToNames() {
  return this.toname.toArray(new String[this.toname.size()]);
}

public ResponseEmail addCc(String cc) {
  this.cc.add(cc);
  return this;
}

public ResponseEmail addCc(String[] ccs) {
  this.cc.addAll(Arrays.asList(ccs));
  return this;
}

public ResponseEmail setCc(String[] ccs) {
  this.cc = new ArrayList<String>(Arrays.asList(ccs));
  return this;
}

public String[] getCcs() {
  return this.cc.toArray(new String[this.cc.size()]);
}

public ResponseEmail setFrom(String from) {
  this.from = from;
  return this;
}

public String getFrom() {
  return this.from;
}

public ResponseEmail setFromName(String fromname) {
  this.fromname = fromname;
  return this;
}

public String getFromName() {
  return this.fromname;
}

public ResponseEmail setReplyTo(String replyto) {
  this.replyto = replyto;
  return this;
}

public String getReplyTo() {
  return this.replyto;
}


public ResponseEmail setSubject(String subject) {
  this.subject = subject;
  return this;
}

public String getSubject() {
  return this.subject;
}

public ResponseEmail setText(String text) {
  this.text = text;
  return this;
}

public String getText() {
  return this.text;
}


public JSONObject getFilters() {
  return this.respModifierSmtpApi.getFilters();
}


public ResponseEmail addContentId(String attachmentName, String cid) {
      this.contents.put(attachmentName, cid);
      return this;
}

public Map getContentIds() {
      return this.contents;
}

public ResponseEmail addHeader(String key, String val) {
  this.headers.put(key, val);
  return this;
}

public Map getHeaders() {
  return this.headers;
}

public MyExperimentalApi getSMTPAPI() {
  return this.respModifierSmtpApi;
}

}

public static class Response {
    private int code;
    private boolean success;
    private String message;

    public Response(int code, String msg) {
      this.code = code;
      this.success = code == 200;
      this.message = msg;
    }

    public int getCode() {
      return this.code;
    }

    public boolean getStatus() {
      return this.success;
    }

    public String getMessage() {
      return this.message;
    }

}//类(class)结束响应

Answer 1

您可以更改导入以节省一些行

import java.util.Arrays
import java.util.HashMap
import java.util.Iterator

变成了

import java.util.{Arrays, HashMap, Iterator}

可以为您生成 getter 和 setter。如果您使用 val 或 var 声明构造函数参数，这就是 Scala 类的一个功能。

您的类(class)的简化版本变为:

class ResponseEmail(var to: ArrayList[String], var cc: ArrayList[String])

此 getter 为 cc 和 to，setter 为 cc_= 和 to_=

scala> res6.
asInstanceOf   cc   cc_=   isInstanceOf   to   toString   to_=