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我最近一直在使用 r,rserve 和 ggplot。

这段代码在 R 控制台中执行时，会按预期直接呈现带有两个条形的图表。png(file='Yash_GenderVsTotalAccountBalance.png',width=400,height=350,res=72) ggplot(data=YashCustomersAccounts, aes(x=GENDER_DESC,y=ACCOUNT_BALANCE)) + geom_bar(stat='identity') dev.离开（）

但是当我使用 Rserve 从 JAVA 调用相同的代码（涉及 ggplot 调用）时，它会创建一个空白 png。代码如下。

package RRnD;
import java.awt.*;
import org.rosuda.REngine.*;
import org.rosuda.REngine.Rserve.*;

public class PlottingGenderVsTotalAccountBalance {

    public static void main(String[] args) throws RserveException {
        try {
            RConnection c = new RConnection(); // make a new local connection on default port (6311)
            System.out.println("1. Connection created ----------------------------------------------------------------------");            
            System.out.println("Working directory = "+c.eval("getwd()").asString());
            System.out.println("2. Working dir read ----------------------------------------------------------------------");
            c.eval("YashCustomers <- read.csv('YashCustomer.csv', header=TRUE)");
            c.eval("YashAccounts <- read.csv('YashAccount.csv', header=TRUE)");
            c.eval("YashCustomersAccounts <- merge(YashCustomers,YashAccounts, by='CUSTOMER_ID')");
            System.out.println("3. Data.frames read ----------------------------------------------------------------------");

            c.eval("library(ggplot2)");
            c.eval("require(ggplot2)");
            System.out.println("4. ggplot2 loaded ----------------------------------------------------------------------");

            c.eval("png(file='Yash_GenderVsTotalAccountBalance.png',width=400,height=350,res=72)");
            c.parseAndEval("ggplot(data=YashCustomersAccounts, aes(x=GENDER_DESC,y=ACCOUNT_BALANCE)) + geom_bar(stat='identity');dev.off()");            
            System.out.println("5. plotting done ----------------------------------------------------------------------");

            REXP xp = c.parseAndEval("r=readBin('Yash_GenderVsTotalAccountBalance.png','raw',1024*1024)");
            c.parseAndEval("unlink('Yash_GenderVsTotalAccountBalance.jpg'); r");
            Image img = Toolkit.getDefaultToolkit().createImage(xp.asBytes());
            System.out.println("img = "+img);
            System.out.println("6. File reading done ----------------------------------------------------------------------");

            System.out.println("10. All done ----------------------------------------------------------------------");            
            c.close();
        } catch (REngineException ree) {
            System.out.println("REngineException ...");
            System.out.println(ree.getMessage());
        } catch (Exception e) {
            System.out.println("Exception ...");
            System.out.println(e.getMessage());
        }
    }

}

注意：- 如果我像以下行一样进行简单的绘图调用，而不是 ggplot 调用，它可以正常工作。png 图像已正确创建。c.parseAndEval("plot(YashCustomers['CUSTOMER_ID']);dev.off()"); ... 而不是 ... c.parseAndEval("ggplot(data=YashCustomersAccounts, aes(x=GENDER_DESC,y=ACCOUNT_BALANCE)) + geom_bar(stat='identity');dev.off()");

请帮助我找到问题。非常感谢，--Yash

4

1 回答 1

3

在控制台中，ggplot 自动绘制图像。但是在从 Rserver 调用 ggplot plotting 时，我们需要显式地打印图像。

c.parseAndEval("print(ggplot(data=YashCustomersAccounts, aes(x=GENDER_DESC,y=ACCOUNT_BALANCE)) + geom_bar(stat='identity'));dev.off()");
于 2013-07-02T06:57:17.947 回答