如何解决为什么我的输出没有保存为文件？
我正在创建一个接受用户输入的应用程序，将其发送到我的pccalc方法，并在按下GUI类（不存在）中的提交按钮时打开pw类窗口以显示结果。我现在想做的是，一旦调用displayC方法，将输出打印到我的textArea到一个.txt文件中。您可以在下面看到我尝试过的内容，但是什么也没发生，而且我不确定从这里去哪里。
预期的输出将是display和displayC方法，它们都将出现在输出中，然后再以txt格式的文件名作为内部版本名称保存到文件中。
打印方法：
package pcbuilder;
public class pccalc {
public void display() {
curWatt = cpu + cpuO + mobo + gpu + fastStore + slowStore + store + exStore + fan + sound; ////(http://www.buildcomputers.net/power-consumption-of-pc-components.html) for high end Mobo
System.out.printf("The max PSU wattage estimate is: " + curWatt + ".%n");
System.out.println("We suggest a minimum of 80+ Gold rating.");
System.out.println("A wattage of even 100w - 200w less is doable!");
}
public void displayC(String n,String cb,String cl,String gb,String gl,String fs,String ss,String sa,String fq,String cf) {
curWatt = cpu + cpuO + mobo + gpu + fastStore + slowStore + store + exStore + fan + sound;
System.out.printf("%nBuild Name: %s",buildName);
System.out.printf("%nCPU - %s %s: %d",cb,cl,cpu);
System.out.printf("%nCPU OC Needed: %d",cpuO);
System.out.printf("%nMotherboard: %d",mobo);
System.out.printf("%nGPU - %s %s: %d",gb,gl,gpu);
System.out.printf("%nSSD/NVME - %s: %d",fs,fastStore);
System.out.printf("%nHDD - %s: %d",ss,slowStore);
System.out.printf("%nUnused Sata/NVME - %s: %d",sa,store);
System.out.printf("%nCD/DVD/BlueRay - %s: %d",fq,exStore);
System.out.printf("%nFans - %s: %d",cf,fan);
System.out.printf("%nOverhead for Sound: %d",sound);
System.out.printf("%nTotal Estimated Wattage: %d%n",curWatt);
}
}
在窗口中显示结果的类
package pcbuilder;
import java.awt.EventQueue;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class pw {
test nt = new test();
private JFrame framePU;
JLabel lblNewLabel = new JLabel("Your Max PSU Estimate!");
JScrollPane scrollPane_1 = new JScrollPane();
JTextArea psuArea = new JTextArea();
PrintStream printStream = new PrintStream(new CustomOutputStream(psuArea));
JScrollPane scrollPane = new JScrollPane();
JButton btnAdv = new JButton("Advanced Breakdown");
pccalc pcp = new pccalc("");
String in = "";
String cbrand = "N/A";
String cline = "N/A" ;
String oclock = "";
String gbrand = "N/A";
String gline = "N/A";
String fstorage = "0";
String sstorage = "0";
String savailable = "0";
String fquarter = "0";
String cfan = "0";
String soverhead = "";
String fn = in + ".txt";
int btnct = 0;
/**
* Launch the application.
*/
public void newScreen(String n,String oc,String cf,String so) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
lblNewLabel.setText("A different label");
in = n;
cbrand = cb;
cline = cl;
oclock = oc;
gbrand = gb;
gline = gl;
fstorage = fs;
sstorage = ss;
savailable = sa;
fquarter = fq;
cfan = cf;
soverhead = so;
//A method from the pccalc class that recalculates based on the strings passed through.
pcp.reCalc(in,cbrand,cline,oclock,gbrand,gline,fstorage,sstorage,savailable,fquarter,cfan,soverhead);
pcp.display();
framePU.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public pw() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
framePU = new JFrame();
framePU.setBounds(100,100,450,348);
framePU.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
framePU.getContentPane().setLayout(null);
lblNewLabel.setHorizontalAlignment(SwingConstants.CENTER);
lblNewLabel.setBounds(128,6,200,16);
framePU.getContentPane().add(lblNewLabel);
scrollPane_1.setBounds(6,26,438,246);
framePU.getContentPane().add(scrollPane_1);
scrollPane_1.setViewportView(psuArea);
JButton btnSave = new JButton("Save");
btnSave.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (btnct != 1) {
pcp.displayC(in,cfan);
}
PrintStream fileStream = null;
try {
fileStream = new PrintStream(new FileOutputStream(in));
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
System.setOut(fileStream);
}
});
btnSave.setBounds(45,284,86,29);
framePU.getContentPane().add(btnSave);
btnAdv.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
pcp.displayC(in,cfan);
btnAdv.setEnabled(false);
btnct++;
}
});
btnAdv.setBounds(214,187,29);
framePU.getContentPane().add(btnAdv);
scrollPane.setBounds(22,354,230);
System.setOut(printStream);
System.setErr(printStream);
}
}
解决方法
将输出写到System.out并使用System.setOut来更改其指向的内容，从长远来看最终会造成混乱。我建议将PrintStream传递给pccalc.display和pccalc.displayC方法，这样就不必更改System.out：
public void display(PrintStream out) {
curWatt = cpu + cpuO + mobo + gpu + fastStore + slowStore + store + exStore + fan + sound; ////(http://www.buildcomputers.net/power-consumption-of-pc-components.html) for high end Mobo
out.printf("The max PSU wattage estimate is: " + curWatt + ".%n");
out.println("We suggest a minimum of 80+ Gold rating.");
out.println("A wattage of even 100w - 200w less is doable!");
}
每次调用以下方法时，请不要忘记传递正确的输出流：
pcp.display(printStream);
现在写入新文件很容易：
try (PrintStream fileStream = new PrintStream(new FileOutputStream(name of your file here))) {
pcp.display(fileStream);
pcp.displayC(fileStream,the rest of your long parameter list here);
} catch (FileNotFoundException e1) {
// display an error dialog to the user here
}
我还建议您为您的方法和变量取有意义的名称-从长远来看，您会感激的
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