Question

我想用JFreeChart制作一个饼图并使用我从XML文件中获取的变量

Methode类：

package Statistik;

import xmlModul.XmlLoader;

public class Data {
    XmlLoader xml = new XmlLoader();

    int deleted;
    int created;
    int edited;

    public int getDeleted() {
        return deleted;
    }

    public void setDeleted(int deleted) {
        this.deleted = deleted;
    }

    public int getCreated() {
        return created;
    }

    public void setCreated(int created) {
        this.created = created;
    }

    public int getEdited() {
        return edited;
    }

    public void setEdited(int edited) {
        this.edited = edited;
    }



    public void setDeletedValue(String s) {
       xml.setStringByTagName("Deleted", "Statistik", s);
    }

    public void setCreatedValue(String s) {
        xml.setStringByTagName("Created", "Statistik", s);
    }

    public void setEditedValue(String s) {
        xml.setStringByTagName("Edited", "Statistik", s);
    }

    public int getDeletedValue() {
        return Integer.parseInt(xml.getStringByTagName("Deleted", "Statistik"));
    }

    public int getCreatedValue() {
        return Integer.parseInt(xml.getStringByTagName("Created", "Statistik"));
    }

    public int getEditedValue() {
        return Integer.parseInt(xml.getStringByTagName("Edited", "Statistik"));
    }

    public void setAll(String d, String c, String e){
        xml.setStringByTagName("Deleted", "Statistik", d);
        xml.setStringByTagName("Created", "Statistik", c);
        xml.setStringByTagName("Edited", "Statistik", e);
    }

}

统计类中的按钮调用：

    DefaultPieDataset pieDataset = new DefaultPieDataset();
    Data data = new Data();

    int created = data.getCreatedValue();
    int deleted = data.getDeletedValue();
    int edited = data.getEditedValue();

    pieDataset.setValue("one", new Integer(15));
    pieDataset.setValue("two", new Integer(40));
    pieDataset.setValue("created", new Integer(created));
    pieDataset.setValue("edited", edited);
    pieDataset.setValue("deleted", deleted);

    JFreeChart chart = ChartFactory.createPieChart("Pie Chart", pieDataset, true, true, true);
    ChartFrame frame = new ChartFrame("Pie Chart", chart);

    frame.setSize(600, 800);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);

在我尝试使用变量之前，我只使用了

之类的语句

pieDataset.setValue("one", new Integer(15));

它有效。但是现在我尝试使用int变量deleted，edited和created，但它无论如何都不起作用。

这是我的错误输出：

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: " 0 "
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:569)
    at java.lang.Integer.parseInt(Integer.java:615)
    at Statistik.Data.getCreatedValue(Data.java:65)
    at Statistik.StatistikWithFreeChart_USE_THIS.jButton1ActionPerformed(StatistikWithFreeChart_USE_THIS.java:65)
    at Statistik.StatistikWithFreeChart_USE_THIS.access$000(StatistikWithFreeChart_USE_THIS.java:8)
    at Statistik.StatistikWithFreeChart_USE_THIS$1.actionPerformed(StatistikWithFreeChart_USE_THIS.java:26)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6525)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6290)
    at java.awt.Container.processEvent(Container.java:2234)
    at java.awt.Component.dispatchEventImpl(Component.java:4881)
    at java.awt.Container.dispatchEventImpl(Container.java:2292)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
    at java.awt.Container.dispatchEventImpl(Container.java:2278)
    at java.awt.Window.dispatchEventImpl(Window.java:2739)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:719)
    at java.awt.EventQueue$4.run(EventQueue.java:717)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:716)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

修改我尝试用

设置数据

data.setAll("10", "20", "5");

并且它工作但是当我在另一个按钮中使用此方法时，它不会取出这个值，所以我需要在方法中设置它，但我必须从xml中取出它。

Answer 1

问题是您正在解析XML文件中的数字，但您的数字周围有空格。方法Integer.parseInt不接受数字周围的空格，传递给它的字符串只能包含数字。

在Java中，您可以使用方法String.trim()来删除字符串开头和结尾的空格。您可以使用它来清除从XML文件中获取的数字，然后再将其传递给Integer.parseInt（或者，您编写代码使用像JAXB这样的XML数据绑定工具，但只有在您的XML格式具有适当的XML格式时才有效XML模式定义）

要修复您的代码（请注意，Integer.parseInt的所有行最后都有trim()）：

public int getDeletedValue() {
    return Integer.parseInt(xml.getStringByTagName("Deleted", "Statistik").trim());
}

public int getCreatedValue() {
    return Integer.parseInt(xml.getStringByTagName("Created", "Statistik").trim());
}

public int getEditedValue() {
    return Integer.parseInt(xml.getStringByTagName("Edited", "Statistik").trim());
}

Answer 2

错误消息告诉您需要知道的全部内容：输入字符串中有空格，因此无法将字符串解析为整数。

因此，在您的函数getDeletedValue()，getCreatedValue()和getEditedValue()中，您需要执行trim（）以删除这些不必要的空白。例如：

public int getCreatedValue() {
    return Integer.parseInt(xml.getStringByTagName("Created", "Statistik").trim());
}

变量作为图表中的参数

2 个答案: