为什么我的输出没有保存为文件？

Question

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，当按下 GUI class（不存在）中的提交按钮时，会打开 pw class window 显示结果。我现在要做的是在调用 displayC 方法后将输出打印到我的 textArea 到 .txt 文件中。您可以在下面看到我尝试过的内容，但没有任何反应，我不确定从这里该何去何从。

预期的输出将是 display 和 displayC 方法，它们在保存到以构建名称作为 txt 格式的文件名的文件之前都出现在输出中。

打印的方法：

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);

    }
}

Class 在 window

中显示结果

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 cb, String cl, String oc, String gb, String gl, String fs, String ss, String sa, String fq, 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, cbrand, cline, gbrand, gline, fstorage, sstorage, savailable, fquarter, 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, cbrand, cline, gbrand, gline, fstorage, sstorage, savailable, fquarter, cfan);
                btnAdv.setEnabled(false);
                btnct++;
            }
        });
        btnAdv.setBounds(214, 284, 187, 29);
        framePU.getContentPane().add(btnAdv);
        
        scrollPane.setBounds(22, 354, 354, 230);
        System.setOut(printStream);
        System.setErr(printStream);
    }
}

Answer 1

将输出写入 System.out 并使用 System.setOut 更改它指向的内容最终导致长运行混乱。我建议将 PrintStream 传递给 pccalc.display 和 pccalc.displayC 方法，这样您就不必更改 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!");
}

不要忘记在每次调用这些方法时传递正确的输出流：

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
}

我还建议你给你的方法和变量起有意义的名字——你会在很长一段时间内感谢自己运行

为什么我的输出没有保存为文件？

Why isn't my output being saved as a file?

java

io

swing

text-files