本文主要是介绍内存数据库 HSQLDB，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
应用
在JUnit单元测试中，由于，很多时候没有真实数据库环境，所以，我们很自然的会借助内存数据库HSQLDB。内存数据库非常轻量级，当内存数据库关闭后，内存中的数据也随之消失。代码虽然简单，但还是贴出来，呵呵，供以后复制粘贴方便。
jdbcDriver in pom.xml of Maven:
<dependency><groupId>org.hsqldb</groupId><artifactId>hsqldb</artifactId><version>2.3.2</version></dependency>package shuai.study.memorydb;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class MemoryDB {private static Connection connection = null;private static Statement statement = null;private static PreparedStatement preparedStatement = null;private static ResultSet resultSet = null;// Load jdbcDriverstatic {try {Class.forName("org.hsqldb.jdbcDriver");} catch (ClassNotFoundException e) {e.printStackTrace();}}// Get DB connectionpublic static Connection getConnection() {if (connection == null) {try {connection = DriverManager.getConnection("jdbc:hsqldb:mem:mdb", "shuai", "123");} catch (SQLException e) {e.printStackTrace();}}return connection;}// Get DB statementpublic static Statement getStatement() {if (connection == null) {getConnection();}if (statement == null) {try {statement = connection.createStatement();} catch (SQLException e) {e.printStackTrace();}}return statement;}// Execute SQLpublic static void executeSQL(String sql) {if (statement == null) {getStatement();}try {statement.executeUpdate(sql);} catch (SQLException e) {e.printStackTrace();}}// Get resultSetpublic static ResultSet executeQuerySQL(String sql) {if (connection == null) {getConnection();}try {preparedStatement = connection.prepareStatement(sql);resultSet = preparedStatement.executeQuery();} catch (SQLException e) {e.printStackTrace();}return resultSet;}// Print resultSetpublic static void resultPrint(ResultSet resultSet) {try {int columnCount = resultSet.getMetaData().getColumnCount();String columnValue = null;while (resultSet.next()) {for (int n = 1; n <= columnCount; n++) {columnValue = resultSet.getString(n);if (n == columnCount) {System.out.println(columnValue);} else {System.out.print(columnValue + "\t");}}}} catch (SQLException e) {e.printStackTrace();}}// Close DBpublic static void closeDB() {try {if (resultSet != null) {resultSet.close();}if (preparedStatement != null) {preparedStatement.close();}if (statement != null) {statement.close();}if (connection != null) {connection.close();}} catch (SQLException e) {e.printStackTrace();}}public static void main(String[] args) {MemoryDB.executeSQL("CREATE TABLE EMPLOYEE(ID INTEGER, NAME VARCHAR(20), SEX VARCHAR(10), TEAM VARCHAR(20))");MemoryDB.executeSQL("INSERT INTO EMPLOYEE VALUES(1,'shuai', 'male', 'FMC')");MemoryDB.executeSQL("INSERT INTO EMPLOYEE VALUES(2,'hellen', 'female', 'MUS')");MemoryDB.executeSQL("INSERT INTO EMPLOYEE VALUES(3,'mery', 'female', 'SDM')");MemoryDB.executeSQL("COMMIT");ResultSet resultSet = MemoryDB.executeQuerySQL("SELECT * FROM EMPLOYEE");MemoryDB.resultPrint(resultSet);MemoryDB.closeDB();}
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