我已经在谷歌上搜索同样的问题很长一段时间了，这里是我的解决方案：使用documents 4j和microsoft office 2010（未尝试较新版本）（不需要在后台运行）。此解决方案将.rtf转换为.pdf
POM文件：

<dependencies>
    <dependency>
        <groupId>com.documents4j</groupId>
        <artifactId>documents4j-api</artifactId>
        <version>0.2.1</version>
    </dependency>       

    <dependency>
        <groupId>com.documents4j</groupId>
        <artifactId>documents4j-util-conversion</artifactId>
        <version>0.2.1</version>
    </dependency>

    <dependency>
        <groupId>com.documents4j</groupId>
        <artifactId>documents4j-transformer</artifactId>
        <version>0.2.1</version>
    </dependency>

    <dependency>
        <groupId>com.documents4j</groupId>
        <artifactId>documents4j-util-all</artifactId>
        <version>0.2.1</version>
    </dependency>

    <dependency>
        <groupId>com.documents4j</groupId>
        <artifactId>documents4j-local</artifactId>
        <version>0.2.1</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.8.0-beta2</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>1.8.0-beta2</version>
    </dependency>
    <dependency>
        <groupId>com.documents4j</groupId>
        <artifactId>documents4j-util-standalone</artifactId>
        <version>1.0.3</version>
    </dependency>
    <dependency>
        <groupId>com.documents4j</groupId>
        <artifactId>documents4j-transformer-msoffice-word</artifactId>
        <version>1.0.3</version>
    </dependency>
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>23.0</version>
    </dependency>
</dependencies>

包括所有的！在.rtf文件中，你需要一些字体和类似的东西。在java中使用的例子：

import com.documents4j.api.DocumentType;
import com.documents4j.api.IConverter;
import com.documents4j.job.LocalConverter;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

/**
 *
 * @author Neon/Jan Madle
 */
public class NewMain {

/**
 * @param args the command line arguments
 * @throws java.io.FileNotFoundException
 */
public static void main(String[] args) throws FileNotFoundException,             IOException, InterruptedException, ExecutionException {

    ByteArrayOutputStream bo = new ByteArrayOutputStream();

    InputStream in = new BufferedInputStream(new FileInputStream(System.getProperty("user.dir") + File.separator +"out.rtf"));
    IConverter converter = LocalConverter.builder()
            .baseFolder(new File(System.getProperty("user.dir") + File.separator +"test"))
            .workerPool(20, 25, 2, TimeUnit.SECONDS)
            .processTimeout(5, TimeUnit.SECONDS)
            .build();

    Future<Boolean> conversion = converter
            .convert(in).as(DocumentType.RTF)
            .to(bo).as(DocumentType.PDF)
            .prioritizeWith(1000) // optional
            .schedule();
    conversion.get();
    try (OutputStream outputStream = new FileOutputStream("out.pdf")) {
        bo.writeTo(outputStream);
    }
    in.close();
    bo.close();
}
}

希望有人觉得这个有用！

JODConverter帮助您使用Java将RTF文件转换为PDF。最新版本可以在here中找到。
根据他们的网站
JODConverter是Java OpenDocument Converter，它利用www.example.com在不同的Office格式之间转换文档，OpenOffice.org该网站为OpenDocument和Microsoft Office格式提供了可以说是最好的导入/导出过滤器。