【Java】创建一个Maven管理的Web项目并连接数据库 创建项目 配置Spring 项目结构
使用Maven来构建一个javaee项目，使用spring框架，mysql数据库
首先创建一个项目，选择maven构建，并选择相应的组件。
下一步，这里按照需求更改即可。
这一步，最好自己配一下maven仓库地址，不要使用自带的，并设置一下阿里源，速度快点。
如图，我设置了自己的：
在项目中创建两个文件夹，一个放java代码，一个放资源文件
并选中该文件夹右键设置为root、资源文件夹
导入相关jar包
<dependencies> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.19</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jsp-api</artifactId> <version>2.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.10</version> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet.jsp.jstl/jstl --> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <!-- https://mvnrepository.com/artifact/org.apache.taglibs/taglibs-standard-impl --> <dependency> <groupId>taglibs</groupId> <artifactId>standard</artifactId> <version>1.1.2</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-expression</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-instrument</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-instrument-tomcat</artifactId> <version>4.3.26.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jms</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-messaging</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-oxm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc-portlet</artifactId> <version>4.3.26.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-websocket</artifactId> <version>${spring.version}</version> </dependency> </dependencies>
配置Spring
创建配置文件
在resource中，我们创建一个配置文件用来配置Spring
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd"> <!-- 自动扫描包，实现支持注解的IOC --> <context:component-scan base-package="com.paul" /> <!-- 视图解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver"> <!-- 前缀 --> <property name="prefix" value="/WEB-INF/pages/" /> <!-- 后缀 --> <property name="suffix" value=".jsp" /> </bean> <mvc:annotation-driven/> </beans>
配置web.xml
<servlet> <servlet-name>dispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>dispatcherServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping>
创建一个Controller
@Controller public class helloController { @RequestMapping("hello") public String sayHello(){ System.out.println("hello"); return "success"; } }
这里返回的success是一个jsp
配置数据库
我们使用阿里的druid来创建连接池。
创建一个druid.properties用来配置
driverClassName=com.mysql.jdbc.Driver url=jdbc:mysql:///数据库名称?serverTimezone=Asia/Shanghai username=root password=密码 # 初始化连接数量 initialSize=5 # 最大连接数 maxActive=10 # 最大等待时间 maxWait=3000
这里的时区，如果你的mysql没有设置的话就需要带上，否则会报错。
写一个工具用来封装
import com.alibaba.druid.pool.DruidDataSourceFactory; import sun.misc.IOUtils; import javax.sql.DataSource; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.sql.Connection; import java.sql.SQLException; import java.util.Properties; public class JDBCUtils { private static DataSource ds ; static { try { //1.加载配置文件 Properties pro = new Properties(); //使用ClassLoader加载配置文件，获取字节输入流 InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"); pro.load(is); //2.初始化连接池对象 ds = DruidDataSourceFactory.createDataSource(pro); } catch (Exception e) { e.printStackTrace(); } } /** * 获取连接池对象 */ public static DataSource getDataSource(){ return ds; } /** * 获取连接Connection对象 */ public static Connection getConnection() throws SQLException { return ds.getConnection(); } }
使用的时候也很简单：
JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource()); String sql = "select * from account"; List<Account> users = template.query(sql, new BeanPropertyRowMapper<Account>(Account.class));