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【100天精通Python】Day50：Python Web编程_Django框架从安装到使用

有点d伤 2023-09-10 阅读 11
sqlitejdbcjavafx

注入依赖

    <dependency>
        <groupId>org.xerial</groupId>
        <artifactId>sqlite-jdbc</artifactId>
        <version>3.43.0.0</version>
    </dependency>

工具类


import org.sqlite.SQLiteConnection;

/**
 * @Author cpf
 * @Date 2023/9/8
 */
import java.sql.*;

public class SQLiteUtils {
    private static final String DB_FILE = "src/main/resources/database.db"; // SQLite数据库文件名


    public static void main(String[] args) throws SQLException {
        Connection conn = getConnection();

        //创建表
        String[] columns = new String[]{"id", "name", "age", "gender"};
        createTable(conn, "students", columns);

        //插入
        Object[] column = new Object[]{"name", "age", "gender"};
        Object[] values = new Object[]{"张三", "16", "汉族"};
        insertRecord(conn, "students",column, values);

        //查询所有记录
        ResultSet students = queryAll(conn, "students");
        while (students.next()){
            System.out.println(students.getString("name") + " | " + students.getString("age") + " | " + students.getString("gender"));
        }

        //查询指定字段的记录
        ResultSet resultSet = queryByColumn(conn, "students", "name");
        while (resultSet.next()){
            System.out.println("姓名: " + resultSet.getString("name"));
        }

        //查询指定条件的记录
        String[] column01 = new String[]{"name"};
        Object[] values01 = new Object[]{"张三"};
        ResultSet students1 = queryByCondition(conn, "students", column01, values01);
        while (students1.next()){
            System.out.println(students1.getString("name") + " | " + students1.getString("age") + " | " + students1.getString("gender"));
        }

        /**
         * 更新一条记录
         * @param conn 数据库连接
         * @param tableName 表名
         * @param conditionSet 更新字段的数组
         * @param conditionSetValue 更新字段的数组
         * @param conditions 条件的数组
         * @param conditionsValue 条件值的数组
         */
        String[] conditionSet = new String[]{"age"};
        Object[] conditionSetValue = new Object[]{"45"};

        String[] conditions = new String[]{"id"};
        Object[] conditionsValue = new Object[]{"5"};
        updateRecord(conn, "students", conditionSet, conditionSetValue, conditions, conditionsValue);

        //根据条件删除数据
        String[] conditions02 = new String[]{"id"};
        Object[] conditionsValue02 = new Object[]{"5"};
        deleteRecord(conn, "students", conditions02, conditionsValue02);

        //根据ID删除数据
        deleteRecordById(conn, "students", "4");

        closeConnection(conn);
    }

    /**
     * 创建SQLite数据库连接
     * @return 数据库连接
     */
    public static Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName("org.sqlite.JDBC");
            conn = DriverManager.getConnection("jdbc:sqlite:" + DB_FILE);
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    /**
     * 关闭数据库连接
     * @param conn 数据库连接
     */
    public static void closeConnection(Connection conn) {
        try {
            if (conn != null) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 创建SQLite表
     * @param conn 数据库连接
     * @param tableName 表名
     * @param columns 列名和数据类型的数组
     */
    public static void createTable(Connection conn, String tableName, String[] columns) {
        StringBuilder sql = new StringBuilder();
        sql.append("CREATE TABLE IF NOT EXISTS ").append(tableName).append(" (");
        for (int i = 0; i < columns.length; i++) {
            sql.append(columns[i]).append(" ").append(getColumnType(columns[i]));
            if (i != columns.length - 1) {
                sql.append(",");
            }
        }
        sql.append(")");
        try (Statement stmt = conn.createStatement()) {
            System.out.println("建表sql: " + sql.toString());
            stmt.executeUpdate(sql.toString());
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取列的数据类型
     * @param columnName 列名
     * @return 数据类型
     */
    private static String getColumnType(String columnName) {
        /*if (columnName.equalsIgnoreCase("id")) {
            return "INTEGER PRIMARY KEY";
        } else if (columnName.equalsIgnoreCase("name")) {
            return "TEXT";
        } else if (columnName.equalsIgnoreCase("age")) {
            return "INTEGER";
        } else if (columnName.equalsIgnoreCase("gender")) {
            return "TEXT";
        } else {
            return "TEXT";
        }*/
        if (columnName.equalsIgnoreCase("id")) {
            return "INTEGER PRIMARY KEY";
        } else {
            return "TEXT";
        }
    }

    /**
     * 插入一条记录
     * @param conn 数据库连接
     * @param tableName 表名
     * @param columns 字段的数组
     * @param values 值的数组
     */
    public static void insertRecord(Connection conn, String tableName, Object[] columns, Object[] values) {
        StringBuilder sql = new StringBuilder();
        sql.append("INSERT INTO ").append(tableName).append(" (");
        for (int i = 0; i < columns.length; i++) {
            sql.append(columns[i].toString()).append(",");
        }
        sql.deleteCharAt(sql.length() - 1);
        sql.append(") VALUES (");
        for (int i = 0; i < columns.length; i++) {
            sql.append("?,");
        }
        sql.deleteCharAt(sql.length() - 1);
        sql.append(")");
        System.out.println("插入: " + sql.toString());
        try (PreparedStatement pstmt = conn.prepareStatement(sql.toString())) {
            for (int i = 0; i < values.length; i++) {
                pstmt.setObject(i + 1, values[i]);
            }
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 查询所有记录
     * @param conn 数据库连接
     * @param tableName 表名
     * @return 查询结果
     */
    public static ResultSet queryAll(Connection conn, String tableName) {
        StringBuilder sql = new StringBuilder();
        sql.append("SELECT * FROM ").append(tableName);
        System.out.println("查询所有记录: " + sql.toString());
        try {
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery(sql.toString());
            return rs;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 查询指定字段的记录
     * @param conn 数据库连接
     * @param tableName 表名
     * @param columnName 列名
     * @return 查询结果
     */
    public static ResultSet queryByColumn(Connection conn, String tableName, String columnName) {
        StringBuilder sql = new StringBuilder();
        sql.append("SELECT ").append(columnName).append(" FROM ").append(tableName);
        try{
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery(sql.toString());
            return rs;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 查询指定条件的记录
     * @param conn 数据库连接
     * @param tableName 表名
     * @param conditions 条件字段的数组
     * @param values 条件值的数组
     * @return 查询结果
     */
    public static ResultSet queryByCondition(Connection conn, String tableName, String[] conditions, Object[] values) {
        StringBuilder sql = new StringBuilder();
        sql.append("SELECT * FROM ").append(tableName).append(" WHERE ");
        for (int i = 0; i < conditions.length; i++) {
            sql.append(conditions[i]).append("=?");
            if (i != conditions.length - 1) {
                sql.append(" AND ");
            }
        }
        System.out.println("询指定条件的记录: " + sql.toString());
        try{
            PreparedStatement pstmt = conn.prepareStatement(sql.toString());
            for (int i = 0; i < values.length; i++) {
                pstmt.setObject(i + 1, values[i]);
            }
            return pstmt.executeQuery();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 更新一条记录
     * @param conn 数据库连接
     * @param tableName 表名
     * @param conditionSet 更新字段的数组
     * @param conditionSetValue 更新字段的数组
     * @param conditions 条件的数组
     * @param conditionsValue 条件值的数组
     */
    public static void updateRecord(Connection conn, String tableName, String[] conditionSet, Object[] conditionSetValue, String[] conditions, Object[] conditionsValue) {
        StringBuilder sql = new StringBuilder();
        sql.append("UPDATE ").append(tableName).append(" SET ");
        for (int i = 0; i < conditionSet.length; i++) {
            sql.append(conditionSet[i]).append("=?");
            if (i != conditionSet.length - 1) {
                sql.append(",");
            }
        }
        sql.append(" WHERE ");
        for (int i = 0; i < conditions.length; i++) {
            sql.append(conditions[i]).append("=?");
            if (i != conditions.length - 1) {
                sql.append(" AND ");
            }
        }
        try{
            System.out.println("更新一条记录: " + sql.toString());
            PreparedStatement pstmt = conn.prepareStatement(sql.toString());
            for (int i = 0; i < conditionSetValue.length; i++) {
                pstmt.setObject(i + 1, conditionSetValue[i]);
            }
            for (int i = 0; i < conditionsValue.length; i++) {
                pstmt.setObject(i + conditionsValue.length + 1, conditionsValue[i]);
            }
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 删除一条记录
     * @param conn 数据库连接
     * @param tableName 表名
     * @param conditions 条件的数组
     * @param conditionsValue 条件值的数组
     */
    public static void deleteRecord(Connection conn, String tableName, String[] conditions, Object[] conditionsValue) {
        StringBuilder sql = new StringBuilder();
        sql.append("DELETE FROM ").append(tableName).append(" WHERE ");
        for (int i = 0; i < conditions.length; i++) {
            sql.append(conditions[i]).append("=?");
            if (i != conditions.length - 1) {
                sql.append(" AND ");
            }
        }
        try{
            System.out.println("根据条件删除数据: " + sql.toString());
            PreparedStatement pstmt = conn.prepareStatement(sql.toString());
            for (int i = 0; i < conditionsValue.length; i++) {
                pstmt.setObject(i + 1, conditionsValue[i]);
            }
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 根据ID删除一条记录
     * @param conn 数据库连接
     * @param tableName 表名
     * @param id ID值
     */
    public static void deleteRecordById(Connection conn, String tableName, String id) {
        StringBuilder sql = new StringBuilder();
        sql.append("DELETE FROM ").append(tableName).append(" WHERE id=?");

        try{
            System.out.println("根据条件删除数据: " + sql.toString());
            PreparedStatement pstmt = conn.prepareStatement(sql.toString());
            pstmt.setString(1, id);
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}
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