IOUtils复制方法不能正常工作

Question

复制方法给出了以下错误：

类型InputStream中的方法副本(FileInputStream，OutputStream)不适用于参数(FileInputStream、StringWriter、String)

..。即使我有3个参数，而且IOUtils确实有

copy(InputStream, Writer, String)法

这是我的代码：

import java.awt.BorderLayout;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.StringWriter;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.SwingConstants;

import org.apache.poi.util.IOUtils;

@SuppressWarnings("serial")
public class AboutDialog extends JFrame {
    private final String fileLocation = "resources/Contents.html";
    private FileInputStream htmlStream;
    private JLabel lblMessage;

    public AboutDialog() {
        String message;
        setType(Type.POPUP);
        setTitle("About");
        setResizable(false);
        setEnabled(false);
        getContentPane().setLayout(new BorderLayout(0, 0));
        try {
            htmlStream = new FileInputStream(fileLocation);
            StringWriter writer = new StringWriter();
            IOUtils.copy(htmlStream, writer, "UTF-8");
            message = writer.toString();
            lblMessage = new JLabel(message);
            lblMessage.setHorizontalAlignment(SwingConstants.CENTER);
            getContentPane().add(lblMessage);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }       
    }

    public void display() {
        JOptionPane.showMessageDialog(null, lblMessage);
    }
}

Answer 1

我想您的意思是导入org.apache.commons.io.IOUtils而不是org.apache.poi.util.IOUtils。

前者有很多copy()方法，后者只有copy(InputStream, OutputStream)。

Answer 2

apache中的IOUtils只包含2个params方法。https://poi.apache.org/apidocs/org/apache/poi/util/IOUtils.html