Subsidy(补贴表) 字段名 类型 注释 其他 id int 序号 主键，非空 subsidyname varchar(50) 考勤 空 Amount decimal(10) 补贴金额 空 根据以上内容用java写出增删改查方法类

以下是使用Java语言实现的增删改查方法类：

import java.math.BigDecimal;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class SubsidyDao {
    private Connection conn = null;
    private PreparedStatement pstmt = null;
    private ResultSet rs = null;

    // 连接数据库
    public Connection getConnection() throws Exception {
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/test";
        String user = "root";
        String password = "123456";
        conn = DriverManager.getConnection(url, user, password);
        return conn;
    }

    // 关闭连接
    public void closeConnection() throws Exception {
        if (rs != null) {
            rs.close();
        }
        if (pstmt != null) {
            pstmt.close();
        }
        if (conn != null) {
            conn.close();
        }
    }

    // 添加补贴记录
    public void addSubsidy(Subsidy subsidy) throws Exception {
        conn = getConnection();
        String sql = "INSERT INTO subsidy (id, subsidyname, Amount) VALUES (?, ?, ?)";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, subsidy.getId());
        pstmt.setString(2, subsidy.getSubsidyname());
        pstmt.setBigDecimal(3, subsidy.getAmount());
        pstmt.executeUpdate();
        closeConnection();
    }

    // 删除补贴记录
    public void deleteSubsidy(int id) throws Exception {
        conn = getConnection();
        String sql = "DELETE FROM subsidy WHERE id=?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, id);
        pstmt.executeUpdate();
        closeConnection();
    }

    // 修改补贴记录
    public void updateSubsidy(Subsidy subsidy) throws Exception {
        conn = getConnection();
        String sql = "UPDATE subsidy SET subsidyname=?, Amount=? WHERE id=?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, subsidy.getSubsidyname());
        pstmt.setBigDecimal(2, subsidy.getAmount());
        pstmt.setInt(3, subsidy.getId());
        pstmt.executeUpdate();
        closeConnection();
    }

    // 查询所有补贴记录
    public List<Subsidy> queryAllSubsidy() throws Exception {
        conn = getConnection();
        String sql = "SELECT * FROM subsidy";
        pstmt = conn.prepareStatement(sql);
        rs = pstmt.executeQuery();
        List<Subsidy> list = new ArrayList<>();
        while (rs.next()) {
            Subsidy subsidy = new Subsidy();
            subsidy.setId(rs.getInt("id"));
            subsidy.setSubsidyname(rs.getString("subsidyname"));
            subsidy.setAmount(rs.getBigDecimal("Amount"));
            list.add(subsidy);
        }
        closeConnection();
        return list;
    }

    // 根据id查询补贴记录
    public Subsidy querySubsidyById(int id) throws Exception {
        conn = getConnection();
        String sql = "SELECT * FROM subsidy WHERE id=?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, id);
        rs = pstmt.executeQuery();
        Subsidy subsidy = null;
        if (rs.next()) {
            subsidy = new Subsidy();
            subsidy.setId(rs.getInt("id"));
            subsidy.setSubsidyname(rs.getString("subsidyname"));
            subsidy.setAmount(rs.getBigDecimal("Amount"));
        }
        closeConnection();
        return subsidy;
    }
}

其中，Subsidy类如下所示：

public class Subsidy {
    private int id;
    private String subsidyname;
    private BigDecimal amount;

    public Subsidy() {}

    public Subsidy(int id, String subsidyname, BigDecimal amount) {
        this.id = id;
        this.subsidyname = subsidyname;
        this.amount = amount;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getSubsidyname() {
        return subsidyname;
    }

    public void setSubsidyname(String subsidyname) {
        this.subsidyname = subsidyname;
    }

    public BigDecimal getAmount() {
        return amount;
    }

    public void setAmount(BigDecimal amount) {
        this.amount = amount;
    }
}

使用方法：

public class Main {
    public static void main(String[] args) {
        SubsidyDao dao = new SubsidyDao();

        // 添加补贴记录
        Subsidy subsidy1 = new Subsidy(1, "考勤", new BigDecimal("1000.00"));
        try {
            dao.addSubsidy(subsidy1);
        } catch (Exception e) {
            e.printStackTrace();
        }

        // 查询所有补贴记录
        List<Subsidy> list = null;
        try {
            list = dao.queryAllSubsidy();
        } catch (Exception e) {
            e.printStackTrace();
        }
        for (Subsidy subsidy : list) {
            System.out.println(subsidy.getId() + " " + subsidy.getSubsidyname() + " " + subsidy.getAmount());
        }

        // 修改补贴记录
        Subsidy subsidy2 = new Subsidy(1, "出勤", new BigDecimal("1500.00"));
        try {
            dao.updateSubsidy(subsidy2);
        } catch (Exception e) {
            e.printStackTrace();
        }

        // 查询特定补贴记录
        Subsidy subsidy3 = null;
        try {
            subsidy3 = dao.querySubsidyById(1);
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println(subsidy3.getId() + " " + subsidy3.getSubsidyname() + " " + subsidy3.getAmount());

        // 删除补贴记录
        try {
            dao.deleteSubsidy(1);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}