这里写目录标题
- 一、简介
- 二、使用
- 1. Java项目中
- （1）引入驱动
- （2）工具类
- （3）调用举例
- 2. sqlite-devel in linux
- sqlite-devel
- 使用
- 三、更多应用
- 1. 数据类型
- 2. 如何存储日期和时间
- 3. 备份
一、简介
- 非常轻量级，都没有服务器进程（mysql必须要有mysqld.service 3306）
- 一个.db或.sqlite文件就是一个数据库, 非常方便备份和传输，只要复制文件就可以
- sqlite 是本地数据库，不能远程。安全！
- SQLite 在任何时刻只允许一个写入操作执行，其他写入操作需要排队
- 数据库就是一个文件，这个文件可以在任意位置，任意后缀名，建议用.db 或者 .sqlite 作为后缀
二、使用
1. Java项目中
（1）引入驱动
<dependency>
<groupId>org.xerial</groupId>
<artifactId>sqlite-jdbc</artifactId>
<version>3.8.11.2</version>
</dependency>
（2）工具类
- SqlLiteHelper
package sample.common.sqlLite;
import sample.common.utils.LogUtil;
import java.lang.reflect.Field;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.logging.Logger;
/**
* @Author admin
* @Date 2023/4/4 11:20
*/
public class SqlLiteHelper {
private Connection connection;
private Statement statement;
private ResultSet resultSet;
private String dbFilePath; // db文件的位置
Logger logger = LogUtil.installFormatter(Logger.getLogger(SqlLiteHelper.class.getSimpleName()));
/**
* 每次创建都将建立一个连接
* @param dbFilePath
* @throws ClassNotFoundException
* @throws SQLException
*/
public SqlLiteHelper(String dbFilePath) throws ClassNotFoundException, SQLException{
this.dbFilePath = dbFilePath;
connection = getConnection(dbFilePath);
}
public Connection getConnection(String dbFilePath) throws ClassNotFoundException, SQLException {
Connection conn = null;
Class.forName("org.sqlite.JDBC");
conn = DriverManager.getConnection("jdbc:sqlite:" + dbFilePath);
return conn;
}
private Connection getConnection() throws ClassNotFoundException, SQLException {
if (null == connection) connection = getConnection(dbFilePath);
return connection;
}
private Statement getStatement() throws SQLException, ClassNotFoundException {
if (null == statement) statement = getConnection().createStatement();
return statement;
}
/**返回对象**/
public <T> T executeQuery(String sql, ResultSetExtractor<T> rse) throws SQLException, ClassNotFoundException {
try {
resultSet = getStatement().executeQuery(sql);
T rs = rse.extractData(resultSet);
return rs;
} finally {
destroyed();
}
}
/**返回对象集合**/
public <T> List<T> executeQuery(String sql, RowMapper<T> rm) throws SQLException, ClassNotFoundException {
List<T> rsList = new ArrayList<T>();
try {
resultSet = getStatement().executeQuery(sql);
while (resultSet.next()) {
rsList.add(rm.mapRow(resultSet, resultSet.getRow()));
}
} finally {
destroyed();
}
return rsList;
}
public <T> List<T> executeQueryList(String sql, Class<T> clazz) throws SQLException, ClassNotFoundException, IllegalAccessException, InstantiationException {
List<T> rsList = new ArrayList<T>();
try {
resultSet = getStatement().executeQuery(sql);
while (resultSet.next()) {
T t = clazz.newInstance();
for (Field field : t.getClass().getDeclaredFields()) {
field.setAccessible(true);
field.set(t,resultSet.getObject(field.getName()));
}
rsList.add(t);
}
} finally {
destroyed();
}
return rsList;
}
public <T> T executeQuery(String sql, Class<T> clazz) throws SQLException, ClassNotFoundException, IllegalAccessException, InstantiationException {
try {
resultSet = getStatement().executeQuery(sql);
T t = clazz.newInstance();
for (Field field : t.getClass().getDeclaredFields()) {
field.setAccessible(true);
// ---> 连接断开了
field.set(t,resultSet.getObject(field.getName()));
}
return t;
} finally {
destroyed();
}
}
public int count(String sql) throws SQLException, ClassNotFoundException, IllegalAccessException, InstantiationException {
try {
resultSet = getStatement().executeQuery(sql);
if(resultSet.next()){
return resultSet.getInt(1);
}
} finally {
destroyed();
}
return 0;
}
/**返回更新成功的条数**/
public int executeUpdate(String sql) throws SQLException, ClassNotFoundException {
try {
int c = getStatement().executeUpdate(sql);
return c;
} finally {
destroyed();
}
}
/**执行多个更新**/
public void executeUpdate(String...sqls) throws SQLException, ClassNotFoundException {
try {
for (String sql : sqls) {
getStatement().executeUpdate(sql);
}
} finally {
destroyed();
}
}
public void executeUpdate(List<String> sqls) throws SQLException, ClassNotFoundException {
try {
for (String sql : sqls) {
getStatement().executeUpdate(sql);
}
} finally {
destroyed();
}
}
/**数据插入更新**/
public int executeInsert(String tableName, Map<String,Object> param) throws SQLException, ClassNotFoundException {
try {
StringBuffer sql = new StringBuffer();
sql.append("INSERT INTO ");
sql.append(tableName);
sql.append(" ( ");
for (String key : param.keySet()) {
sql.append(key);
sql.append(",");
}
sql.delete(sql.length()-1,sql.length());
sql.append(") VALUES ( ");
for (String key : param.keySet()) {
sql.append("'");
sql.append(param.get(key));
sql.append("',");
}
sql.delete(sql.length()-1,sql.length());
sql.append(");");
int c = getStatement().executeUpdate(sql.toString());
return c;
} finally {
destroyed();
}
}
/**数据库资源关闭和释放**/
public void destroyed() {
// 每一次crud都关闭了所有的资源
try {
if (null != statement) {
statement.close();
statement = null;
}
if (null != connection) {
connection.close();
connection = null;
}
if (null != resultSet) {
resultSet.close();
resultSet = null;
}
} catch (SQLException e) {
logger.info("Sqlite数据库关闭时异常"+e.getMessage());
}
}
}
- 结果集实现
package sample.common.sqlLite;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* @Author admin
* @Date 2023/4/4 11:25
*/
public interface RowMapper<T> {
public abstract T mapRow(ResultSet rs, int index) throws SQLException;
}
package sample.common.sqlLite;
import java.sql.ResultSet;
/**
* @Author admin
* @Date 2023/4/4 11:24
*/
public interface ResultSetExtractor<T> {
public abstract T extractData(ResultSet resulltSet);
}
（3）调用举例
- 加载库和表
SqliteHelper sqlLiteHelper = new SqlLiteHelper(dbFilePath); // 库
String createCard = "create table if not exists card(id integer primary key autoincrement,name text,lastReport text)";
sqlLiteHelper.executeUpdate(createCard); // 建表
2. sqlite-devel in linux
sqlite-devel
centos7.6
https://www.sqlite.org/download.html
yum install sqlite-devel
使用
sqlite 连接不需要用户名和密码
[root@localhost trdp]# sqlite3 trdp.db
SQLite version 3.7.17 2013-05-20 00:56:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .database
# 输出显示了当前连接的数据库文件路径。
seq name file
--- --------------- ----------------------------------------------------------
0 main /usr/local/tynoo/trdp/trdp.db
sqlite> .tables
msgs port
sqlite> .schema port
CREATE TABLE port
(
port String
);
sqlite> select * from msgs;
sqlite> insert into port (port) values (null);
sqlite> .quit
三、更多应用
1. 数据类型
https://www.sqlite.net.cn/datatype3.html
2. 如何存储日期和时间
3. 备份
因为sqlite基于文件存储的特殊特性，
它的备份本质上是这个sqlite_database.db这个文件的备份，尤其是在单用户或低并发场景下，SQLite 3 的数据备份可以通过简单的文件复制cp来实现
但是这里就存在几个问题：
（1）文件 被锁定，比如说正在写入数据
（2）事务不一致，你复制的时候，某个事务正在进行中
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