本篇文章我们通过一个简单的应用程序一起来了解下H2在spring boot应用、以及在junit中如何使用（其他类似的数据库还有HSQL、Derby）
1.H2的特性
- 速度快、完全开源、支持JDBC API
- 同时提供内嵌和server两种模式
- 提供基于浏览器的控制台
- 非常轻量，jar只有1.5M左右
2.和其他数据库的对比
| H2 | Derby | HSQLDB | MySQL | PostgreSQL | |
| Pure Java | Yes | Yes | Yes | No | No |
| Memory Mode | Yes | Yes | Yes | No | No |
| Encrypted Database | Yes | Yes | Yes | No | No |
| ODBC Driver | Yes | No | No | Yes | Yes |
| Fulltext Search | Yes | No | No | Yes | Yes |
| Multi Version Concurrency | Yes | No | Yes | Yes | Yes |
| Footprint (jar/dll size) | ~1 MB | ~2 MB | ~1 MB | ~4 MB | ~6 MB |
3.在spring boot应用中引入H2，在pom.xml中追加如下依赖
com.h2database h2 runtime
4.完整的工程结构如下
5.完整的pom.xml文件
4.0.0 chengf.falcon spring-boot-data-h2 0.0.1-SNAPSHOT org.springframework.boot spring-boot-starter-parent 2.0.2.RELEASE pom import org.springframework.boot spring-boot-starter-jdbc org.springframework.boot spring-boot-starter-web com.h2database h2 runtime org.springframework.boot spring-boot-starter-test test org.springframework.boot spring-boot-maven-plugin
6.启动类
/**
*
*/
package chengf.falcon.spring.data.h2;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
/**
* @author: 作者： chengaofeng
* @date: 创建时间：2018-07-20 16:02:57
* @Description: TODO
* @version V1.0
*/
@SpringBootApplication
@RestController
public class H2DataApp implements CommandLineRunner {
public static void main(String[] args) {
SpringApplication.run(H2DataApp.class, args);
}
@Autowired
H2CommandProcessor processor;
/*
* (non-Javadoc)
*
* @see org.springframework.boot.CommandLineRunner#run(java.lang.String[])
*/
@Override
public void run(String... args) throws Exception {
processor.create();
}
@RequestMapping("/insert")
public void insert(@RequestParam String id) {
processor.insert(new User(id, "xuefei", 27));
}
@RequestMapping("/query")
public User query(@RequestParam String id) {
return processor.query(id);
}
}
实现CommandLineRunner在启动时创建好相应的表
7.数据库操作类
/**
*
*/
package chengf.falcon.spring.data.h2;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowCallbackHandler;
import org.springframework.stereotype.Component;
/**
* @author: 作者： chengaofeng
* @date: 创建时间：2018-07-20 15:58:47
* @Description: TODO
* @version V1.0
*/
@Component
public class H2CommandProcessor {
@Autowired
JdbcTemplate jdbcTemplate;
public void create() {
jdbcTemplate.execute("CREATE TABLE USER (ID VARCHAR2(128),NAME VARCHAR2(128),AGE NUMBER(3), SCORE NUMBER(12,4))");
}
public void insert(User user) {
String sql = "INSERT INTO USER VALUES(?, ?, ?,?)";
jdbcTemplate.update(sql, new Object[] { user.getId(), user.getName(), user.getAge(), 89.75d });
}
public User query(String id) {
User user = new User();
String sql = String.format("SELECT ID, NAME, AGE FROM USER WHERE ID = ?");
jdbcTemplate.query(sql, new Object[] { id }, new RowCallbackHandler() {
public void processRow(ResultSet rs) throws SQLException {
user.setId(rs.getString("id"));
user.setName(rs.getString("name"));
user.setAge(rs.getInt("age"));
for (int i = 0; i< rs.getMetaData().getColumnCount() ; i++) {
System.out.println(rs.getMetaData().getColumnName(i));
System.out.println(rs.getMetaData().getColumnTypeName(i));
System.out.println(rs.getMetaData().getColumnType(i));
}
}
});
return user;
}
}
8.对应的bean
/**
*
*/
package chengf.falcon.spring.data.h2;
/**
* @author: 作者： chengaofeng
* @date: 创建时间：2018-07-20 15:59:47
* @Description: TODO
* @version V1.0
*/
public class User {
private String id;
private String name;
private int age;
/**
* @param name
* @param age
*/
public User(String id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
/**
*
*/
public User() {
// TODO Auto-generated constructor stub
}
/**
* @return the id
*/
public String getId() {
return id;
}
/**
* @param id
* the id to set
*/
public void setId(String id) {
this.id = id;
}
/**
* @return the name
*/
public String getName() {
return name;
}
/**
* @param name
* the name to set
*/
public void setName(String name) {
this.name = name;
}
/**
* @return the age
*/
public int getAge() {
return age;
}
/**
* @param age
* the age to set
*/
public void setAge(int age) {
this.age = age;
}
}
9.配置文件
spring.h2.console.enabled: true spring.datasource.url: jdbc:h2:mem:testdb;MODE=Oracle;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE
10.启动后访问 http://localhsot:8080/h2-console,进入页面控制台
点击connect按钮进入
可以看到创建的USER表
11.Junit中使用H2
package chengf.falcon.spring.data.h2;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.h2.jdbcx.JdbcDataSource;
import org.junit.Assert;
import org.junit.Test;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowCallbackHandler;
/**
*
*/
/**
* @author: 作者： chengaofeng
* @date: 创建时间：2018-08-09 18:49:57
* @Description: TODO
* @version V1.0
*/
public class H2DoubleTest {
JdbcTemplate jdbcTemplate;
@Test
public void test() {
JdbcDataSource dd = new JdbcDataSource();
dd.setUrl("jdbc:h2:mem:testdb;MODE=Oracle;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE");
jdbcTemplate = new JdbcTemplate(dd);
create();
insert();
User user = query("3");
Assert.assertEquals("chengf", user.getName());
}
public void create() {
jdbcTemplate.execute("CREATE TABLE USER (ID VARCHAR2(128),NAME VARCHAR2(128),AGE NUMBER(3), SCORE NUMBER(12,4))");
}
public void insert() {
String sql = "INSERT INTO USER VALUES(?, ?, ?,?)";
jdbcTemplate.update(sql, new Object[] { "3", "chengf", 20, 89.75d });
}
public User query(String id) {
User user = new User();
String sql = String.format("SELECT ID, NAME, AGE,SCORE FROM USER WHERE ID = ?");
jdbcTemplate.query(sql, new Object[] { id }, new RowCallbackHandler() {
public void processRow(ResultSet rs) throws SQLException {
user.setId(rs.getString("id"));
user.setName(rs.getString("name"));
user.setAge(rs.getInt("age"));
for (int i = 1; i<= rs.getMetaData().getColumnCount() ; i++) {
System.out.print(rs.getMetaData().getColumnName(i));
System.out.print(":");
System.out.print(rs.getMetaData().getColumnTypeName(i));
System.out.print(":");
System.out.print(rs.getMetaData().getPrecision(i));
System.out.print(".");
System.out.println(rs.getMetaData().getScale(i));
// System.out.println(rs.getMetaData().getColumnType(i));
}
}
});
return user;
}
}
这个junit简单演示了直接利用h2创建数据库连接以及创建表，插入和查询功能
- 查看图片附件