Java Swing 实现的个人所得税计算模拟器源码分享

GUI 界面实现

Swing 开发中，线程安全是个关键点。主窗口创建必须在 EDT（事件分发线程）上执行，所以我们使用了 SwingUtilities.invokeLater。

package com.tax.calculator;

import javax.swing.*;
import javax.swing.border.TitledBorder;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.math.BigDecimal;
import java.util.Map;

/**
 * 个税计算器主界面
 */
public class TaxCalculatorFrame extends JFrame {
    
    private JTextField incomeField;
    private JTextField specialDeductionField;
    private JTextField additionalDeductionField;
    private JTextArea resultArea;
    private JComboBox<String> deductionTypeCombo;
    private JLabel standardLabel;
    
    public TaxCalculatorFrame() {
        initUI();
        initData();
    }
    
    private void initUI() {
        setTitle("个人所得税计算模拟器 v1.0");
        setSize(800, 600);
        setLocationRelativeTo(null);
        
        // 主面板
        JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
        mainPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        
        // 输入面板
        mainPanel.add(createInputPanel(), BorderLayout.NORTH);
        
        // 结果面板
        mainPanel.add(createResultPanel(), BorderLayout.CENTER);
        
        // 按钮面板
        mainPanel.add(createButtonPanel(), BorderLayout.SOUTH);
        
        add(mainPanel);
    }
    
    private JPanel createInputPanel() {
        JPanel panel = new JPanel(new GridLayout(5, 2, 10, 10));
        panel.setBorder(BorderFactory.createTitledBorder(
            BorderFactory.createLineBorder(Color.GRAY),
            "个税计算参数输入",
            TitledBorder.LEFT,
            TitledBorder.TOP
        ));
        
        // 年度总收入
        panel.add(new JLabel("年度总收入 (¥):"));
        incomeField = new JTextField("120000");
        panel.add(incomeField);
        
        // 专项扣除
        panel.add(new JLabel("三险一金专项扣除 (¥):"));
        specialDeductionField = new JTextField("10000");
        panel.add(specialDeductionField);
        
        // 专项附加扣除
        panel.add(new JLabel("专项附加扣除 (¥):"));
        additionalDeductionField = new JTextField("3000");
        panel.add(additionalDeductionField);
        
        // 扣除标准查询
        panel.add(new JLabel("扣除项目查询:"));
        JPanel queryPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
        deductionTypeCombo = new JComboBox<>();
        queryPanel.add(deductionTypeCombo);
        standardLabel = new JLabel("标准：¥0");
        queryPanel.add(standardLabel);
        panel.add(queryPanel);
        
        return panel;
    }
    
    private JScrollPane createResultPanel() {
        resultArea = new JTextArea();
        resultArea.setEditable(false);
        resultArea.setFont(new Font("宋体", Font.PLAIN, 14));
        resultArea.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        
        JScrollPane scrollPane = new JScrollPane(resultArea);
        scrollPane.setBorder(BorderFactory.createTitledBorder("计算结果"));
        
        return scrollPane;
    }
    
    private JPanel createButtonPanel() {
        JPanel panel = new JPanel(new FlowLayout(FlowLayout.CENTER, 20, 10));
        
        // 计算按钮
        JButton calculateBtn = new JButton("计算个税");
        calculateBtn.setFont(new Font("微软雅黑", Font.BOLD, 14));
        calculateBtn.setBackground(new Color(70, 130, 180));
        calculateBtn.setForeground(Color.WHITE);
        calculateBtn.setPreferredSize(new Dimension(120, 40));
        
        calculateBtn.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                calculateTax();
            }
        });
        
        // 清除按钮
        JButton clearBtn = new JButton("清除结果");
        clearBtn.setFont(new Font("微软雅黑", Font.PLAIN, 14));
        clearBtn.setPreferredSize(new Dimension(120, 40));
        clearBtn.addActionListener(e -> clearResults());
        
        // 税率表按钮
        JButton rateTableBtn = new JButton("查看税率表");
        rateTableBtn.setFont(new Font("微软雅黑", Font.PLAIN, 14));
        rateTableBtn.setPreferredSize(new Dimension(120, 40));
        rateTableBtn.addActionListener(e -> showTaxRateTable());
        
        panel.add(calculateBtn);
        panel.add(clearBtn);
        panel.add(rateTableBtn);
        
        return panel;
    }
    
    private void initData() {
        // 初始化扣除类型下拉框
        Map<String, BigDecimal> standards = TaxCalculator.getSpecialDeductionStandards();
        for (String key : standards.keySet()) {
            deductionTypeCombo.addItem(key);
        }
        
        // 添加下拉框监听
        deductionTypeCombo.addActionListener(e -> {
            String selected = (String) deductionTypeCombo.getSelectedItem();
            if (selected != null) {
                BigDecimal standard = standards.get(selected);
                standardLabel.setText(String.format("标准：¥%.2f", standard));
            }
        });
        
        // 默认选择第一个
        if (deductionTypeCombo.getItemCount() > 0) {
            deductionTypeCombo.setSelectedIndex(0);
        }
    }
    
    /**
     * 执行个税计算
     */
    private void calculateTax() {
        try {
            // 获取输入值
            double income = Double.parseDouble(incomeField.getText());
            double special = Double.parseDouble(specialDeductionField.getText());
            double additional = Double.parseDouble(additionalDeductionField.getText());
            
            // 验证输入
            if (income < 0 || special < 0 || additional < 0) {
                JOptionPane.showMessageDialog(this,
                    "输入值不能为负数！",
                    "输入错误",
                    JOptionPane.WARNING_MESSAGE);
                return;
            }
            
            // 执行计算
            TaxCalculator.TaxResult result = TaxCalculator.calculateAnnualTax(
                income, special, additional);
            
            // 显示结果
            displayResult(result);
            
        } catch (NumberFormatException ex) {
            JOptionPane.showMessageDialog(this,
                "请输入有效的数字！",
                "输入错误",
                JOptionPane.ERROR_MESSAGE);
        }
    }
    
    /**
     * 显示计算结果
     */
    private void displayResult(TaxCalculator.TaxResult result) {
        StringBuilder sb = new StringBuilder();
        sb.append("=== 个人所得税计算结果 ===\n\n");
        sb.append(String.format("年度总收入：¥%,.2f\n", result.getTotalIncome()));
        sb.append(String.format("应纳税所得额：¥%,.2f\n", result.getTaxableIncome()));
        sb.append(String.format("适用税率档次：%s\n", result.getTaxBracket()));
        sb.append(String.format("应纳个人所得税：¥%,.2f\n", result.getTaxAmount()));
        sb.append(String.format("年度税后收入：¥%,.2f\n\n", result.getAfterTaxIncome()));
        
        // 计算月度数据
        double monthlyTax = result.getTaxAmount() / 12;
        double monthlyAfterTax = result.getAfterTaxIncome() / 12;
        
        sb.append("=== 月度数据估算 ===\n");
        sb.append(String.format("月度平均纳税：¥%,.2f\n", monthlyTax));
        sb.append(String.format("月度税后收入：¥%,.2f\n\n", monthlyAfterTax));
        
        // 添加税务建议
        sb.append("=== 税务优化建议 ===\n");
        if (result.getTaxableIncome() > 0) {
            sb.append("1. 充分利用专项附加扣除项目\n");
            sb.append("2. 合理规划年度收入时间分布\n");
            sb.append("3. 符合条件的捐赠可税前扣除\n");
        } else {
            sb.append("当前收入无需缴纳个人所得税\n");
        }
        
        resultArea.setText(sb.toString());
        resultArea.setCaretPosition(0);
    }
    
    /**
     * 显示税率表
     */
    private void showTaxRateTable() {
        StringBuilder sb = new StringBuilder();
        sb.append("=== 个人所得税税率表（综合所得） ===\n\n");
        sb.append("级数 | 全年应纳税所得额 | 税率 | 速算扣除数\n");
        sb.append("----|-----------------|------|----------\n");
        
        TaxCalculator.TaxBracket[] brackets = new TaxCalculator.TaxBracket[]{
            new TaxCalculator.TaxBracket(0, 36000, 0.03, 0),
            new TaxCalculator.TaxBracket(36000, 144000, 0.10, 2520),
            new TaxCalculator.TaxBracket(144000, 300000, 0.20, 16920),
            new TaxCalculator.TaxBracket(300000, 420000, 0.25, 31920),
            new TaxCalculator.TaxBracket(420000, 660000, 0.30, 52920),
            new TaxCalculator.TaxBracket(660000, 960000, 0.35, 85920),
            new TaxCalculator.TaxBracket(960000, Double.MAX_VALUE, 0.45, 181920)
        };
        
        for (int i = 0; i < brackets.length; i++) {
            TaxCalculator.TaxBracket b = brackets[i];
            String range;
            if (b.getUpperBound() == Double.MAX_VALUE) {
                range = String.format("超过%,.0f 元", b.getLowerBound());
            } else {
                range = String.format("%,.0f - %, .0f 元", 
                    b.getLowerBound(), b.getUpperBound());
            }
            
            sb.append(String.format("%-4d| %-15s | %.1f%% | %, .0f 元\n",
                i + 1, range, b.getRate() * 100, b.getQuickDeduction()));
        }
        
        sb.append("\n注：应纳税所得额 = 年度收入 - 6 万元 (基本扣除) - 专项扣除 - 专项附加扣除\n");
        
        resultArea.setText(sb.toString());
    }
    
    /**
     * 清除结果
     */
    private void clearResults() {
        resultArea.setText("");
    }
}

编译与运行

确保环境已安装 Java 8 或更高版本，并支持 Swing。

# 编译所有 Java 文件
javac -d . com/tax/calculator/*.java

# 运行程序
java com.tax.calculator.PersonalIncomeTaxApp

扩展建议

如果打算在此基础上继续完善，可以考虑以下方向：

1. 数据持久化：添加本地文件保存/加载历史计算记录的功能。
2. 图表展示：引入 JFreeChart 库，将收入与税负比例可视化。
3. 联网更新：增加接口自动同步最新的个税政策与税率调整。
4. 导出功能：支持将计算结果导出为 PDF 或 Excel 格式。

注意事项

本程序仅作为技术学习与演示用途，实际报税请以官方税务系统为准。税率政策如有更新，需相应修改代码中的税率表数据。计算结果仅供参考，不构成专业税务建议。