试图写入文件。我做了研究，确保冲洗并关闭。我以为它可能是在读取消息框为空白而什么也没写，但是做了一个System.out.println以确保它正确地读取了。所以现在不确定。
原始代码：
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.io.*;
public class Form extends Applet implements ActionListener{
private TextField first = new TextField("First Name",12);
private TextField middle = new TextField("I",1);
private TextField last = new TextField("Last Name",15);
private TextField address = new TextField("Address",25);
private TextField city = new TextField("City",20);
private TextField state = new TextField("State",2);
private TextField zip = new TextField("Postal Code",10);
private Button submit =new Button("Submit");
private Button reset = new Button("Reset");
private Button save = new Button("Save");
private Button enlarge = new Button("Enlarge");
private TextArea message = new TextArea();
public void init()
{
GridBagLayout gbl = new GridBagLayout();
setLayout(gbl);
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.WEST;
c.weightx=1.0;
c.weighty=1.0;
c.fill=GridBagConstraints.HORIZONTAL;
c.insets=new Insets(5,5,5,5);
gbl.setConstraints(first,c); add(first);
c.fill=GridBagConstraints.NONE;
gbl.setConstraints(middle,c); add(middle);
c.fill=GridBagConstraints.HORIZONTAL;
gbl.setConstraints(last,c); add(last);
c.gridy=1;
gbl.setConstraints(address,c); add(address);
c.gridy=2;
gbl.setConstraints(city,c); add(city);
c.fill=GridBagConstraints.NONE;
gbl.setConstraints(state,c); add(state);
c.gridy=3;
gbl.setConstraints(zip,c); add(zip);
c.gridy=4;
c.anchor = GridBagConstraints.CENTER;
gbl.setConstraints(submit,c);add(submit);
gbl.setConstraints(reset,c); add(reset);
c.gridy=5;
c.anchor = GridBagConstraints.CENTER;
gbl.setConstraints(save, c); add(save);
gbl.setConstraints(enlarge, c); add(enlarge);
c.gridy=6;
c.gridwidth=3;
c.fill=GridBagConstraints.BOTH;
gbl.setConstraints(message,c);add(message);
submit.addActionListener(this);
reset.addActionListener(this);
enlarge.addActionListener(this);
save.addActionListener(this);
}
public void actionPerformed(ActionEvent event)
{
String initial = middle.getText();
String a=message.getText();
if (initial != null)
initial +=". ";
Object source = event.getSource();
if (source == submit)
{
message.setText(first.getText()+ ' ' +initial+last.getText());
message.append('\n'+address.getText());
message.append('\n'+city.getText()+", " +state.getText());
message.append(' ' +zip.getText());
message.append("\n\nYour message:\n"+a);
}
else if (source == reset)
{
message.setText("");
first.setText("");
middle.setText("");
last.setText("");
address.setText("");
city.setText("");
state.setText("");
zip.setText("");
}
else if (source == enlarge)
{
message.setFont(new Font("Serif", Font.PLAIN, 14));
message.setForeground(Color.BLUE);
message.setText(a);
}
else if (source == save)
{
try{
File file=new File("savedMessage.txt");
PrintWriter pw = new PrintWriter(file);
pw.println(message.getText());
//message.setText("Print was successful")
pw.flush();
pw.close();
System.out.println(message.getText());
}
catch (FileNotFoundException e) {
e.printStackTrace();
System.err.println("Error: " + e.getMessage());
} catch (IOException e) {
e.printStackTrace();
System.err.println("Error: " + e.getMessage());
}
}
}
}
这是用于解决问题的代码：
else if (source == save)
{
try{
f = new File("savedMessage.txt");
bw = new BufferedWriter(new FileWriter(f,true));
bw.write(message.getText());
if(f.canWrite()){
System.out.println("Success");
}
}
catch (FileNotFoundException e) {
e.printStackTrace();
System.err.println("Error: " + e.getMessage());
} catch (IOException e) {
e.printStackTrace();
System.err.println("Error: " + e.getMessage());
}
finally{
try {
bw.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
最佳答案
PrintWriter吞下异常。请参阅Javadoc。您需要致电checkError()。更好的是，使用BufferedWriter不会吞下它们。除非您的小程序已签名，否则您可能正在遇到一个苹果沙箱权限问题。
关于java - PrintWriter未写入文件，尝试添加flush()和close()Java，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13793375/