Java 生成Sqlite的.db文件

import java.io.File;
import java.lang.reflect.Field;
import java.sql.*;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author Zc
 * @date 2022年03月20日 11:24
 */
public class DBUtill {
    private static Connection connection = null;
    private static Statement statement = null;
    private static String username = "zc";
    private static String password = "zc";

    /**
     * 开始事务
     * @param cnn
     */
    public static void beginTransaction(Connection cnn){
        if(cnn!=null){
            try {
                if(cnn.getAutoCommit()){
                    cnn.setAutoCommit(false);
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    /**
     * 提交事务
     * @param cnn
     */
    public static void commitTransaction(Connection cnn){
        if(cnn!=null){
            try {
                if(!cnn.getAutoCommit()){
                    cnn.commit();
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    /**
     * 回滚事务
     * @param cnn
     */
    public static void rollBackTransaction(Connection cnn){
        if(cnn!=null){
            try {
                if(!cnn.getAutoCommit()){
                    cnn.rollback();
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    /**
     * @describe: 设置连接  
     * @params:  
     * @Author: zc  
     * @Date: 2022/03/20
     */
    public static void setConnection(String path) {
        try {
            File f  = new File(path);
            if(!f.exists()){
                File file = new File(path);
                file.mkdirs();
            }
//            声明驱动类型
            Class.forName("org.sqlite.JDBC");
//            设置 sqlite文件路径，等同于mysql连接地址(jdbc:mysql://127.0.0.1:3306/test)
            String url = "jdbc:sqlite:" + path + "\\data.db";
//            获取连接
            connection = DriverManager.getConnection(url, username, password);
//            声明
            statement = connection.createStatement();
        } catch (Exception e) {
            throw new RuntimeException("建立Sqlite连接失败");
        }


    }

    /**
     * @describe: 创建表
     * @params: tableName: 要创建的表的名称 className：项目中Pojo的类名(需要注意的是该类名需要加上包名 如 com.xxx.xxx.xxx)
     * @Author: zc
     * @Date: 2022/03/20
     */
    public synchronized static void create(String tableName, String className) throws SQLException {
        try {
            statement.executeUpdate("DROP TABLE IF EXISTS " + tableName + ";");
//            通过反射，获取传入类名的字段信息
            Field[] fields = Class.forName(className).getDeclaredFields();
            StringBuffer sb = new StringBuffer();
            String reg = " ";
            sb.append("create table " + tableName + " (");
            for (Field field : fields) {
//                设置使用反射时,可以访问私有变量,当pojo的变量设置为private修饰时,isAccessible()得到的值是false，必须要改成true才可以访问
                field.setAccessible(true);
//                通过获得的字段,获取字段类型,和字段名,来定义创建表的字段名和字段类型
                if (field.getType().getName().equals(java.lang.Long.class.getName())) {
                    sb.append(reg + field.getName() + " bigint(20) ");
                } else if (field.getType().getName().equals(java.lang.String.class.getName())) {
                    sb.append(reg + field.getName() + " varchar(255) ");
                } else if (field.getType().getName().equals(java.util.Date.class.getName())) {
                    sb.append(reg + field.getName() + " datetime ");
                } else {
                    sb.append(reg + field.getName() + " int(11) ");
                }
                reg = ",";
            }
            sb.append(") ; ");
            statement.executeUpdate(sb.toString());
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("建表失败，表名称：" + tableName);
        }
    }

    /**
     * @describe: 表中插入数据
     * @params: tableName：表名 list:待插入的对象集合 需要注意的是插入的对象要跟表名对应
     * @Author: zc
     * @Date: 2022/03/20
     */
    public synchronized static <T> int insert(String tableName, List<T> list) throws SQLException {
        StringBuffer declaration = new StringBuffer();
        List<String> dataSqlArray = new ArrayList<>();
        AtomicInteger count = new AtomicInteger();
        beginTransaction(connection);
        try {
            list.stream().map(t -> {
                if (dataSqlArray.size() < 1) {
                    Field[] fields = t.getClass().getDeclaredFields();
                    declaration.append(" (");
                    String reg = "";
                    for (Field field : fields) {
                        field.setAccessible(true);
                        declaration.append(reg + field.getName());
                        reg = ",";
                    }
                    declaration.append(")");
                }
                return t;
            }).forEach((t) -> {
                Field[] fields = t.getClass().getDeclaredFields();
                StringBuffer oneData = new StringBuffer();
                String reg = "";
                oneData.append(" (");

                for (Field field : fields) {
                    try {
                        field.setAccessible(true);
                        if (null == field.get(t) || "".equals(field.get(t))) {
                            oneData.append(reg + null);
                        } else if (field.getType().getName().equals(java.lang.String.class.getName())) {
//                            传入的对象中字段是字符串时,插入数据库需要转义单引号
                            oneData.append(reg + "\'" + field.get(t) + "\'");
//                            传入的对象中字段是日期类型时,先将日期转换为 yyyy-MM-dd 的形式
                        } else if (field.getType().getName().equals(java.util.Date.class.getName())) {
                            String dd = field.get(t).toString();
                            SimpleDateFormat sdf1 = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy", Locale.ENGLISH);
                            SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                            String date = sdf2.format(sdf1.parse(dd));
                            oneData.append(reg + "\'" + date + "\'");
                        } else if (field.getType().getName().equals(java.lang.Integer.class.getName())||field.getType().getName().equals(java.lang.Double.class.getName())){
                            oneData.append(reg + (field.get(t)==null?0:field.get(t)));
                        }else {
                            oneData.append(reg + field.get(t));
                        }
                        reg = ",";
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                oneData.append(")");
                dataSqlArray.add(oneData.toString());
                String retSQL = "INSERT INTO " + tableName + declaration.toString()
                        + " VALUES " + oneData + ";";
                PreparedStatement prep = null;
                try {
                    prep = connection.prepareStatement(retSQL);
                    count.set(count.get()+prep.executeUpdate());
                } catch (SQLException e) {
                    e.printStackTrace();
                    throw new RuntimeException(tableName+"表插入数据失败");
                }
            });
            //之前使用的将所有values(insert(xx,xx,...)values(xx,xx,...),(xx,xx,..)... )
           /* String dataSql = StringUtils.join(dataSqlArray, ",");
            if (dataSql!=null&&!"".equals(dataSql)) {
                String retSQL = "INSERT INTO " + tableName + declaration.toString()
                        + " VALUES " + dataSql + ";";
                PreparedStatement prep = connection.prepareStatement(retSQL);
               count.set(prep.executeUpdate());
            }*/
            //先插入数据后建索引，数据量大时速度会有点提升
            if ("skutm3".equals(tableName)){
                statement.executeUpdate("CREATE INDEX index_tm ON skutm3(tm) ; ");
            }
            //事务提交
            commitTransaction(connection);
        } catch (Exception e) {
            //事务回滚
            rollBackTransaction(connection);
            e.printStackTrace();
            throw new RuntimeException(tableName+"表插入数据失败");
        }
        return count.get();
    }

    /**
     * @describe: 关闭链接
     * @params:
     * @Author: zc
     * @Date: 2022/03/20
     */
    public static void endConnection() {
        try {

            connection.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}