【Java】創建一個Maven管理的Web項目並連接數據庫

使用Maven來構建一個javaee項目，使用spring框架，mysql數據庫

創建項目

首先創建一個項目，選擇maven構建，並選擇相應的組件。

  下一步，這里按照需求更改即可。

 這一步，最好自己配一下maven倉庫地址，不要使用自帶的，並設置一下阿里源，速度快點。

 如圖，我設置了自己的：

 在項目中創建兩個文件夾，一個放java代碼，一個放資源文件

 並選中該文件夾右鍵設置為root、資源文件夾

 導入相關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

創建配置文件

在resource中，我們創建一個配置文件用來配置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">

    <!-- 自動掃描包，實現支持注解的IOC -->
    <context:component-scan base-package="com.paul" />


    <!-- 視圖解析器 -->
    <bean
            class="org.springframework.web.servlet.view.InternalResourceViewResolver"
            id="internalResourceViewResolver">
        <!-- 前綴 -->
        <property name="prefix" value="/WEB-INF/pages/" />
        <!-- 后綴 -->
        <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>

 

創建一個Controller

@Controller
public class helloController {

    @RequestMapping("hello")
    public String sayHello(){
        System.out.println("hello");

        return "success";
    }
}

這里返回的success是一個jsp

配置數據庫

我們使用阿里的druid來創建連接池。

創建一個druid.properties用來配置

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///數據庫名稱?serverTimezone=Asia/Shanghai
username=root
password=密碼
# 初始化連接數量
initialSize=5
# 最大連接數
maxActive=10
# 最大等待時間
maxWait=3000

這里的時區，如果你的mysql沒有設置的話就需要帶上，否則會報錯。

寫一個工具用來封裝

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.加載配置文件
            Properties pro = new Properties();
            //使用ClassLoader加載配置文件，獲取字節輸入流
            InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            pro.load(is);
            //2.初始化連接池對象
            ds = DruidDataSourceFactory.createDataSource(pro);

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

    /**
     * 獲取連接池對象
     */
    public static DataSource getDataSource(){
        return ds;
    }


    /**
     * 獲取連接Connection對象
     */
    public static Connection getConnection() throws SQLException {
        return  ds.getConnection();
    }
}

使用的時候也很簡單：

JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
String sql = "select * from account";
List<Account> users = template.query(sql, new BeanPropertyRowMapper<Account>(Account.class));

項目結構