Java Swing 多线程加载图片（保证顺序一致）

大二的时候做的课程设计，图片管理器，当时遇到图片很多的文件夹，加载顺序非常慢。虽然尝试用多个thread加载图片，却无法保证图片按顺序加载。直到今天学会了使用callable接口和future接口，于是心血来潮实现了这个功能。

废话不多说，看代码。

多线程加载图片（核心）：

package com.lin.imagemgr;

import java.awt.dimension;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.filenamefilter;
import java.io.ioexception;
import java.util.arraylist;
import java.util.list;
import java.util.concurrent.executionexception;
import java.util.concurrent.executorservice;
import java.util.concurrent.executors;
import java.util.concurrent.future;
import java.util.stream.collectors;
import javax.swing.imageicon;
import javax.swing.jlabel;

import net.coobird.thumbnailator.thumbnails;

public class imagemgr {
 private static imagemgr instance = new imagemgr();
 private imagemgr() {}
 public static imagemgr getinstance() {
  return instance;
 }

 //线程池
 private executorservice executor = executors.newfixedthreadpool(8);

 public list<jlabel> loadimages(string path) {
  list<jlabel> images = new arraylist<>();
  file file = new file(path);
  if (!file.isdirectory()) {
   throw new runtimeexception("need directory!");
  }
  file[] files = file.listfiles(new filenamefilter() {

   @override
   public boolean accept(file dir, string name) {
    //thumbnail只支持jpg??
    if (name.endswith(".jpg")) {
     return true;
    }
    return false;
   }
  });

  //并发加载图片，并使用future保存加载结果
  list<future<mylabel>> futures = new arraylist<>();
  for (final file f : files) {
   future<mylabel> future = executor.submit(() -> {
    return new mylabel(f.getname(), f.getabsolutepath());
   });
   futures.add(future);
  }

  //等待所有并发加载返回结果
  try {
   for (future<mylabel> future : futures) {
    mylabel icon = future.get();
    images.add(icon);
   }
  } catch (interruptedexception e) {
   e.printstacktrace();
  } catch (executionexception e) {
   e.printstacktrace();
  }

  //java8使用stream api 进行排序
  list<jlabel> sortedlist = images.stream().sorted().collect(collectors.tolist());

  return sortedlist;
 }

 //继承jlabel并实现comparable接口，从而对jlabel进行排序
 private static class mylabel extends jlabel implements comparable<mylabel>{
  private static final long serialversionuid = 1l;
  private string filename;

  public mylabel(string filename, string fullpath) {
   this.filename = filename;
   //使用thumbnailator生成缩略图
   try {
    bufferedimage bufferedimage = thumbnails.of(fullpath) 
    .size(100, 120)
    .asbufferedimage();
    seticon(new imageicon(bufferedimage));
    setpreferredsize(new dimension(100, 120));
   } catch (ioexception e) {
    e.printstacktrace();
   }
  }

  @override
  public int compareto(mylabel o) {
   int result = this.filename.compareto(o.filename);
   return result;
  }


 }

}

swing界面：

package com.lin.imagemgr;

import java.awt.borderlayout;
import java.awt.dimension;
import java.awt.flowlayout;
import java.util.list;
import javax.swing.jbutton;
import javax.swing.jframe;
import javax.swing.jlabel;
import javax.swing.jpanel;
import javax.swing.jscrollpane;
import javax.swing.jtextfield;

public class mainframe extends jframe{
 private static final long serialversionuid = 1l;
 private jtextfield pathfield;
 private jbutton showbtn;
 private jpanel contentpanel;

 public void init() {
  jpanel toppanel = new jpanel(new flowlayout(flowlayout.left, 5, 0));
  toppanel.setpreferredsize(new dimension(800, 40));
  pathfield = new jtextfield(50);
  showbtn = new jbutton("显示图片");
  toppanel.add(pathfield);
  toppanel.add(showbtn);
  getcontentpane().add(borderlayout.north, toppanel);
  contentpanel = new jpanel();
  contentpanel.setlayout(new flowlayout(flowlayout.left, 5, 5));
  contentpanel.setpreferredsize(new dimension(750, 1800));
  jscrollpane jsp = new jscrollpane(contentpanel);
  getcontentpane().add(borderlayout.center, jsp);

  showbtn.addactionlistener((e) -> {
   try {
    loadimages();
   } catch (exception ex) {
    ex.printstacktrace();
   }
  });

  setsize(800, 650);
  setdefaultcloseoperation(jframe.exit_on_close);
  setlocationrelativeto(null);
  setvisible(true);
 }

 public void loadimages() {
  contentpanel.removeall();
  string path = pathfield.gettext();
  long start = system.currenttimemillis();
  list<jlabel> images = imagemgr.getinstance().loadimages(path);
  for (jlabel label :images) {
   contentpanel.add(label);
  }
  contentpanel.updateui();
  long end = system.currenttimemillis();
  system.out.println("加载需要" + (end - start) + "毫秒！");

 }

 public static void main(string[] args) {
  new mainframe().init();
 }

}

运行结果

在我的电脑上，加载92张图片并渲染到界面上，总共花了1568毫秒。大家可以找一个图片很多的文件夹，尝试加载大量图片的情况。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。