Java应用程序在Eclipse中正常运行,但不是.jar

时间:2010-09-01 14:12:28

标签: java eclipse jar executable-jar

我正在创建一个使用iText创建4个PDF文件的Java应用程序。在创建带有图像的PDF的情况下,.jar会创建一个0字节的文件,并且不会继续执行。但是,当我右键单击>>运行方式>> Java应用程序,它工作得很好。要创建jar,我正在执行以下操作

  • 右键单击src
  • 导出
  • Runnable JAR文件
  • 将所需的库提取到生成的JAR
  • 完成

文件“penguin.jpg”位于src目录下。

这是我的代码

import com.itextpdf.text.*;
import com.itextpdf.text.pdf.PdfPTable;
import com.itextpdf.text.pdf.PdfWriter;
import java.io.FileOutputStream;

public class ITextHelloWorld 
{
    public ITextHelloWorld() throws Exception
    {
        // Create the new document objects
        Document helloWorld = new Document();
        Document bigHello = new Document();
        Document linux = new Document();
        Document tables = new Document();


    /**********************************************************
                        start Big Hello.pdf
    This document is a huge document of text. Approximately 
    28 million characters, 24,391 pages, and 9.5 MB.
     **********************************************************/
    PdfWriter.getInstance(bigHello, new FileOutputStream("Big Hello.pdf"));
    bigHello.open();

    for (int i=0; i <1000000; i++)
    {
        bigHello.add(new Paragraph("Hello World. It's me again."));
    }

    bigHello.close();
    /**********************************************************
                        end Big Hello.pdf
     **********************************************************/

    /**********************************************************
                        start Tables.pdf
    This document will have tables in it
     **********************************************************/

    PdfWriter.getInstance(tables, new FileOutputStream("Tables.pdf"));
    tables.open();

    PdfPTable table=new PdfPTable(4);
    for (int i = 1; i<100; i++)
    {       
        table.addCell("This is cell #" + i + ".\n");
    }

    tables.add(table);
    tables.close();
    /**********************************************************
                        end Tables.pdf
     **********************************************************/

    /**********************************************************
                        start Linux.pdf
    This is a document that has text, graphics, and links.
     **********************************************************/
    PdfWriter.getInstance(linux, new FileOutputStream("Graphics and Text.pdf"));
    linux.open();       
    Image image = Image.getInstance("penguin.jpg");
    linux.add(image);

    linux.add(new Paragraph("Let's talk about Linux. \n\n" +
            "Linux (commonly pronounced /ˈlɪnəks/ LIN-əks in American English, also pronounced " +
            "/ˈlɪnʊks/ LIN-ooks in Europe and Canada) refers to the family of Unix-like computer " +
            "operating systems using the Linux kernel. Linux can be installed on a wide variety of " +
            "computer hardware, ranging from mobile phones, tablet computers and video game consoles, " +
            "to mainframes and supercomputers. Linux is predominantly known for its use " +
            "in servers; in 2009 it held a server market share ranging between 20–40%. Most desktop " +
            "computers run either Microsoft Windows or Mac OS X, with Linux having anywhere from a " +
            "low of an estimated 1–2% of the desktop market to a high of an estimated 4.8%. " +
            "However, desktop use of Linux has become increasingly popular in recent years, partly " +
            "owing to the popular Ubuntu, Fedora, Mint, and openSUSE distributions and the emergence" +
            " of netbooks and smartphones running an embedded Linux."));

    linux.close();
    /**********************************************************
                        end Linux.pdf
     **********************************************************/

    /**********************************************************
                        start Hello World.pdf
    This document is one line of text.
     **********************************************************/
    PdfWriter.getInstance(helloWorld, new FileOutputStream("Hello World.pdf"));
    helloWorld.open();
    helloWorld.add(new Paragraph("Hello World. It's me again."));
    helloWorld.close();
    /**********************************************************
                        end Hello World.pdf
     **********************************************************/

}

public static void main (String args[])
{
    try
    {
        new ITextHelloWorld();
    }

    catch (Exception e)
    {
        System.out.println(e);
    }
}

}

感谢您的帮助! 托马斯

3 个答案:

答案 0 :(得分:4)

托马斯,问题在于,当你创建jar时,你会“弄乱”目录结构。您需要使用以下方法从jar中提取图像:

InputStream stream = this.getClass().getClassLoader()
                              .getResourceAsStream("/images/image.jpg");

您应该根据需要编辑图像的路径。

您的Image代码将如下所示:

Image image = Image.getInstance(this.getClass().getResource("/penguin.jpg"));

相关问题:

  

Java Swing Displaying Images From Within-a Jar

答案 1 :(得分:2)

猜测,问题出在这一行:

Image image = Image.getInstance("penguin.jpg");

由于这是在src目录中,它将最终在JAR文件中。但是,您无法仅使用文件名直接从JAR文件加载文件。

但是,Image.getInstance an overload的{{3}}需要URL,这使得这很容易:

Image image = Image.getInstance(this.getClass().getResource("/penguin.jpg"));

/是src目录或jar文件的根目录,而不是文件系统根目录,以防你想知道。

答案 2 :(得分:0)

在不知道你得到的错误的情况下,我猜这是一个CLASSPATH问题。从命令行运行jar文件时,您需要传递类路径以指向依赖的jar文件,或者系统类路径(环境变量)必须指向运行应用程序所需的所有jar文件。