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我正在尝试从 org.rosuda.REngine.Rserve.RConnection 获取 R 脚本文件，然后从该脚本调用一个函数，但我得到，“错误：找不到函数“main”。

从终端启动 Rserve

> require(Rserve)
Loading required package: Rserve
> Rserve()
Starting Rserve...
 "C:\Users\slenzi\DOCUME~1\R\WIN-LI~1\3.3\Rserve\libs\x64\Rserve.exe"
> Rserve: Ok, ready to answer queries.
Error: could not find function "main"

外部脚本 rdbcTest1.R

require(RJDBC)

main <- function() {
    jdbcDriver <- JDBC(driverClass = dbDriverClass, classPath = dbDriverPath)
    jdbcConnection <- dbConnect(jdbcDriver, dbUrl, dbUser, dbPwd)
    dbResult <- dbGetQuery(jdbcConnection, dbQuery)
    dbDisconnect(jdbcConnection)
    return(dbResult)
}

Java 代码

import org.rosuda.REngine.REXP;
import org.rosuda.REngine.REXPMismatchException;
import org.rosuda.REngine.REngine;
import org.rosuda.REngine.REngineException;
import org.rosuda.REngine.RList;
import org.rosuda.REngine.Rserve.RConnection;
import org.rosuda.REngine.Rserve.RserveException;

REXP result = null;
RConnection c = null;
try {

    c = new RConnection();

    String driverPath = "C:/temp/ojbdc6.jar";
    String scriptPath = "C:/temp/rdbcTest1.R";

    c.assign("dbUser", "foo");
    c.assign("dbPwd", "******");// commented out
    c.assign("dbUrl", "jdbc:oracle:thin:@myhost:1511:ecogtst");
    c.assign("dbDriverClass", "oracle.jdbc.driver.OracleDriver");
    c.assign("dbDriverPath", driverPath);       

    // assign query to execute
    c.assign("dbQuery", "SELECT count(*) FROM prs.members");            

    String evalSource = String.format("try(source(\"%s\", local=TRUE), silent=TRUE)", scriptPath);

    c.eval("evalSource");

    // debug
    result = c.eval("ls()");
    logger.info("REXP debug => " + result.toDebugString());         

    result = c.eval("main()");

} catch (RserveException e) {
    logger.error("error running script test, " + e.getMessage());
} finally {
    if(c != null){
        c.close();
    }
}

输出

evaluating => try(source("C:/temp/rdbcTest1.R", local=TRUE), silent=TRUE)
REXP debug => org.rosuda.REngine.REXPString@61c6bc05[6]{"dbDriverClass","dbDriverPath","dbPwd","dbQuery","dbUrl","dbUser"}

Error: could not find function "main"
error running oracle script test, eval failed, request status: error code: 127

直接从 R 终端运行脚本可以正常工作。当从 RConnection 运行时，我可以看到我分配的变量的值 (c.assign(...)) 但不是来自源脚本的 main() 函数。

我在采购脚本方面缺少什么？如何从脚本访问函数？

谢谢。

**更新**

我得到了以下工作，但如果有人知道为什么 source() 在我上面的示例中似乎不起作用，请告诉我！

RConnection c = ...
REXP x = c.parseAndEval("try(eval(parse(file=\"C:/temp/rdbcTest3.R\")), silent=TRUE)")
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0 回答 0