Spring+SpringMVC+JDBC实现登录的示例(附源码)

2021-04-03 我要评论

有一位程序员去相亲的时候，非常礼貌得说自己是一名程序员，并解释自己是做底层架构的，于是女方听到"底层"两个字，就一脸嫌弃：什么时候能够到中高级？

用久了框架，把原生都忘记了，本章从零开始，熟悉一遍JDBC实现增删改查

开发环境

jdk 1.8
Maven 3.6
Spring、SpringMVC 4.3.18
dbcp2
jsp
Idea

创建项目

创建项目时，我们选择传统的Maven项目结构

创建项目时不要选择任何模板，直接点Next

填写包名及项目名Next --> Finish

在main文件夹下创建webapp --> WEB-INF --> web.xml (如下图)

web.xml内容如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="http://xmlns.jcp.org/xml/ns/javaee"
     xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
     http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
     id="WebApp_ID" version="3.1">
  
  <display-name>Demo-JDBC</display-name>

  <!-- 欢迎页 -->
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

引入jar包，添加Spring、SpringMVC配置

在pom.xml中添加需要用到的jar包

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
     http://maven.apache.org/xsd/maven-4.0.0.xsd">

  <modelVersion>4.0.0</modelVersion>
  <groupId>com.wayne</groupId>
  <artifactId>Demo-JDBC</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <!-- 统一控制jar包版本 -->
  <properties>
    <servlet-version>3.1.0</servlet-version>
    <mysql-version>5.1.38</mysql-version>
    <commons-dbcp2-version>2.1.1</commons-dbcp2-version>
    <dbutil-version>1.6</dbutil-version>
    <spring-version>4.3.18.RELEASE</spring-version>
    <jstl-version>1.2</jstl-version>
  </properties>

  <!-- jar包依赖 -->
  <dependencies>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>${servlet-version}</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql-version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-dbcp2</artifactId>
      <version>${commons-dbcp2-version}</version>
    </dependency>
    <dependency>
      <groupId>commons-dbutils</groupId>
      <artifactId>commons-dbutils</artifactId>
      <version>${dbutil-version}</version>
    </dependency>

    <!-- spring-mvc -->
    <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>

    <!-- spring -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</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>${spring-version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring-version}</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>${jstl-version}</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>Demo-JDBC</finalName>
    <plugins>
      <!-- Tomcat插件 -->
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
        <configuration>
          <port>80</port>
          <path>/</path>
          <uriEncoding>UTF-8</uriEncoding>
        </configuration>
      </plugin>

      <!-- 编译插件 -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
          <encoding>UTF-8</encoding>
        </configuration>
      </plugin>
    </plugins>
  </build>

  <!-- 资源仓库地址： 阿里云仓库 -->
  <repositories>
    <repository>
      <id>public</id>
      <name>aliyun nexus</name>
      <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
      <releases>
        <enabled>true</enabled>
      </releases>
    </repository>
  </repositories>

  <!-- 插件仓库下载地址 -->
  <pluginRepositories>
    <pluginRepository>
      <id>public</id>
      <name>aliyun nexus</name>
      <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
      <releases>
        <enabled>true</enabled>
      </releases>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </pluginRepository>
  </pluginRepositories>
</project>

在resources下创建spring.xml，并添加一下内容

<!-- 自动扫描的包 -->
  <context:component-scan base-package="com.wayne">
    <!-- 扫描是忽略的注解 -->
    <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
  </context:component-scan>

在resources下创建springmvc.xml，并添加一下内容

<!-- 开启自动扫描 -->
  <context:component-scan base-package="com.wayne">
    <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
  </context:component-scan>

  <!-- 开启基于注解的mvc -->
  <mvc:annotation-driven/>

  <!-- 开启静态资源访问 -->
  <mvc:default-servlet-handler/>

  <!-- 配置视图解析器 -->
  <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
    <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
    <property name="prefix" value="/WEB-INF/views/"/>
    <property name="suffix" value=".jsp"/>
  </bean>

此时项目结构如下

配置监听器及中央控制器，在web.xml中添加如下内容

<!-- 监听器 -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:spring.xml</param-value>
  </context-param>

  <!-- 字符过滤器 -->
  <filter>
    <filter-name>encodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
    <init-param>
      <param-name>forceEncoding</param-name>
      <param-value>true</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>encodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <!-- 配置中央控制器 -->
  <servlet>
    <servlet-name>springmvc</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>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

至此，项目基础配置完成，我们顺便将项目所用各包创建完成，稍后介绍各类所起作用，此时项目结构如下

配置数据库连接

在resources下的config.properties中声明我们要访问的数据库

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/db_test
jdbc.username=你的数据库用户名
jdbc.password=你的数据库密码

在utils包下的ConnectionManager中配置数据库连接池

package com.wayne.utils;

import org.apache.commons.dbcp2.BasicDataSource;

import javax.sql.DataSource;
import java.io.IOException;
import java.util.Properties;

/**
 * 数据库连接池
 * @author Wayne
 * @date 2019/5/24
 */
public class ConnectionManager {

  private static BasicDataSource dataSource = new BasicDataSource();
  private static String DRIVER;
  private static String URL;
  private static String USERNAME;
  private static String PASSWORD;

  static {
    try {
      // 加载config.properties中配置的数据库连接信息
      Properties prop = new Properties();
    prop.load(ConnectionManager.class.getClassLoader().getResourceAsStream("config.properties"));
      DRIVER = prop.getProperty("jdbc.driver");
      URL = prop.getProperty("jdbc.url");
      USERNAME = prop.getProperty("jdbc.username");
      PASSWORD = prop.getProperty("jdbc.password");
    } catch (IOException e) {
      e.printStackTrace();
    }
    dataSource.setDriverClassName(DRIVER);
    dataSource.setUrl(URL);
    dataSource.setUsername(USERNAME);
    dataSource.setPassword(PASSWORD);
    
    // 配置数据库连接池参数
    dataSource.setInitialSize(2);
    dataSource.setMaxIdle(5);
    dataSource.setMinIdle(1);
    dataSource.setMaxWaitMillis(5000);
  }

  public static DataSource getConection() {
    return dataSource;
  }
}

在utils下的DBHelp编写CRUD工具类

package com.wayne.utils;

import com.wayne.exception.DataAccessException;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;

import java.sql.SQLException;

/**
 * CRUD工具类
 * @author Wayne
 * @date 2019/5/24
 */
public class DbHelp {

  // 从连接池中获得连接
  private static QueryRunner runner = new QueryRunner(ConnectionManager.getConection());

  /**
   * 新增
   * @param sql 待执行的SQL
   * @param rsh 结果集处理方式
   * @param params SQL中的参数
   * @param <T> 结果的类的详情信息
   * @throws DataAccessException SQL执行错误时抛出的异常
   */
  public static <T> T insert(String sql, ResultSetHandler<T> rsh, Object...params) throws DataAccessException {
    T t = null;
    try {
      t = runner.insert(sql, rsh, params);
    } catch (SQLException e) {
      throw new DataAccessException("执行: " + sql + "异常");
    }
    return t;
  }

  /**
   * @param sql 待执行的SQL
   * @param params 结果集处理方式
   * @throws DataAccessException SQL执行错误时抛出的异常
   */
  public static void update(String sql, Object... params) throws DataAccessException {
    try {
      runner.update(sql, params);
    } catch (SQLException e) {
      throw new DataAccessException("执行: " + sql + "异常");
    }
  }

  /**
   * @param sql 待执行的SQL
   * @param rsh 结果集处理方式
   * @param params SQL中的参数
   * @param <T> 结果的类的详情信息
   * @throws DataAccessException SQL执行错误时抛出的异常
   */
  public static <T> T query(String sql, ResultSetHandler<T> rsh, Object... params) throws DataAccessException {
    T t = null;
    try {
      t = runner.query(sql, rsh, params);
    } catch (SQLException e) {
      throw new DataAccessException("执行: " + sql + "异常");
    }
    return t;
  }
}

在exception包下自定义DataAccessException异常

package com.wayne.exception;

/**
 * 自定义异常类，用于转化sql异常
 * @author Wayne
 * @date 2019/5/24
 */
public class DataAccessException extends RuntimeException {
  private static final long serialVersionUID = 1L;

  public DataAccessException() {

  }

  public DataAccessException(String message) {
    super(message);
  }

  public DataAccessException(Throwable th) {
    super(th);
  }

  public DataAccessException(String message, Throwable th) {
    super(message, th);
  }
}

至此，工具类配置完成，可以开始写页面和接口了，我们顺带将登录页一并创建，此时项目结构如下