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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包含两个条形图的图表。 png(文件='Yash_GenderVsTotalAccountBalance.png'，宽度=400，高度=350，res=72) ggplot(data=YashCustomersAccounts, aes(x=GENDER_DESC,y=ACCOUNT_BALANCE)) + geom_bar(stat='身份') dev.off()
但是当我使用 Rserve 从 JAVA 调用相同的代码(涉及 ggplot 调用)时，它会创建一个空白的 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:- 如果我不使用 ggplot 调用，而是像下面一行那样进行简单的绘图调用，它就可以正常工作。 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()");
请帮助我找出问题所在。 非常感谢， --亚什