我需要Java的代码

好的，以下是使用Java实现港口不同类型货物吞吐趋势和统计港口吞吐量的代码示例：

1. 绘制港口不同类型货物吞吐趋势图

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.renderer.category.BarRenderer;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;

public class PortCargoTrendChart extends JFrame {
    
    public PortCargoTrendChart() {
        super("港口不同类型货物吞吐趋势");
        CategoryDataset dataset = createDataset();
        JFreeChart chart = createChart(dataset);
        ChartPanel chartPanel = new ChartPanel(chart);
        chartPanel.setPreferredSize(new Dimension(500, 300));
        getContentPane().add(chartPanel);
    }
    
    private CategoryDataset createDataset() {
        DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.addValue(100, "货物类型A", "2016年");
        dataset.addValue(150, "货物类型A", "2017年");
        dataset.addValue(200, "货物类型A", "2018年");
        dataset.addValue(250, "货物类型A", "2019年");
        dataset.addValue(300, "货物类型A", "2020年");
        dataset.addValue(120, "货物类型B", "2016年");
        dataset.addValue(170, "货物类型B", "2017年");
        dataset.addValue(220, "货物类型B", "2018年");
        dataset.addValue(270, "货物类型B", "2019年");
        dataset.addValue(320, "货物类型B", "2020年");
        dataset.addValue(140, "货物类型C", "2016年");
        dataset.addValue(190, "货物类型C", "2017年");
        dataset.addValue(240, "货物类型C", "2018年");
        dataset.addValue(290, "货物类型C", "2019年");
        dataset.addValue(340, "货物类型C", "2020年");
        return dataset;
    }
    
    private JFreeChart createChart(CategoryDataset dataset) {
        JFreeChart chart = ChartFactory.createBarChart(
            "港口不同类型货物吞吐趋势", 
            "年份", 
            "吞吐量(单位:万吨)", 
            dataset, 
            PlotOrientation.VERTICAL, 
            true, 
            true, 
            false
        );
        chart.setBackgroundPaint(Color.white);
        CategoryPlot plot = (CategoryPlot) chart.getPlot();
        plot.setBackgroundPaint(Color.lightGray);
        plot.setDomainGridlinePaint(Color.white);
        plot.setRangeGridlinePaint(Color.white);
        BarRenderer renderer = (BarRenderer) plot.getRenderer();
        renderer.setDrawBarOutline(false);
        renderer.setItemMargin(0.2);
        CategoryAxis domainAxis = plot.getDomainAxis();
        domainAxis.setCategoryLabelPositions(CategoryLabelPositions.UP_45);
        domainAxis.setTickLabelFont(new Font("SansSerif", Font.BOLD, 12));
        domainAxis.setTickLabelsVisible(true);
        NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
        rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
        rangeAxis.setTickLabelsVisible(true);
        return chart;
    }
    
    public static void main(String[] args) {
        PortCargoTrendChart chart = new PortCargoTrendChart();
        chart.pack();
        chart.setVisible(true);
    }
}

2. 统计港口吞吐量

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class PortThroughputStatistics {
    
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            // 连接数据库
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/port_throughput";
            String user = "root";
            String password = "123456";
            conn = DriverManager.getConnection(url, user, password);
            System.out.println("成功连接到数据库！");
            
            // 查询港口吞吐量
            stmt = conn.createStatement();
            String sql = "SELECT year, SUM(cargo_volume) AS total_volume FROM throughput GROUP BY year";
            rs = stmt.executeQuery(sql);
            System.out.println("年份\t吞吐量(单位:万吨)");
            while (rs.next()) {
                int year = rs.getInt("year");
                int totalVolume = rs.getInt("total_volume");
                System.out.println(year + "\t" + totalVolume);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) rs.close();
                if (stmt != null) stmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

以上是使用Java实现港口不同类型货物吞吐趋势和统计港口吞吐量的示例代码，您可以根据自己的需要进行修改和完善。