Spring MVC篇二、使用JdbcTemplate进行数据库操作

上一篇只是一个简单的Spring MVC框架，接下来添加一些跟数据库的交互。

一、添加jdbc相关配置

 

在maven中添加相关依赖后，配置数据库访问参数及数据源。数据库参数使用配置文件，代码如下：

jdbc.properties

 jdbc.driver=com.mysql.jdbc.Driver
 jdbc.url=jdbc:mysql://localhost:3306/sampledb
 jdbc.username=root
 jdbc.password=123456
 jdbc.initialSize=5
 jdbc.maxActive=10
 jdbc.minIdle=5
 jdbc.maxIdle=10
 jdbc.timeBetweenEvictionRunsMillis=3600000
 jdbc.minEvictableIdleTimeMillis=3600000
 jdbc.testOnBorrow=true
 jdbc.validationQuery=SELECT 1 FROM DUAL

在app-servlet.xml中添加数据源配置和jdbcTemplate配置：

<bean id="jdbcConfig" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location">
        <value>classpath:jdbc.properties</value>
    </property>
</bean>
<bean id="databasesource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="${jdbc.driver}"/>
    <property name="url" value="${jdbc.url}"/>
    <property name="username" value="${jdbc.username}"/>
    <property name="password" value="${jdbc.password}"/>
    <property name="maxActive" value="${jdbc.maxActive}"/>
    <property name="initialSize" value="${jdbc.initialSize}"/>
    <property name="maxIdle" value="${jdbc.maxIdle}"/>
    <property name="minIdle" value="${jdbc.minIdle}"/>
    <property name="timeBetweenEvictionRunsMillis"     value="${jdbc.timeBetweenEvictionRunsMillis}"/>
    <property name="minEvictableIdleTimeMillis" value="${jdbc.minEvictableIdleTimeMillis}"/>
    <property name="testOnBorrow" value="${jdbc.testOnBorrow}"/>
    <property name="validationQuery" value="${jdbc.validationQuery}"/>
</bean>
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
    <property name="dataSource" ref="databasesource"/>
</bean>

二、实现一个使用用户名为super，密码为123456的用户登录过程

2.1 添加User实体类

User.java代码如下：

 public class User {
     private Long id;
     private String username;
     private String email;
     private String password;
     private Long credit;
     private Date lastVisitTime;
     private String lastVisitIp;
     //setter、getter
 }

2.2 实现对数据库的访问操作

新建UserDao.java，在UserDao类上添加@Repository注解

首先在该类中装配JdbcTemplate，使用@Autowired注解

@Autowired
private JdbcTemplate jdbcTemplate;

然后在里面添加一个根据用户名和密码查询用户的方法：

 public User findUser(final String username, final String password) {
         String sql = "select id,user_name, credit from t_user_info where user_name = ? and password = ?";
         User user = null;
         try {
             RowMapper<User> rm = ParameterizedBeanPropertyRowMapper.newInstance(User.class);
             user = (User) jdbcTemplate.queryForObject(sql, new Object[]{username, password}, rm);
         }catch (Exception e){
             e.printStackTrace();
         }
         return user;
     }

2.3 添加UserService.java类，代码如下：

 @Service("userService")
 public class UserService {
     @Autowired
     UserDao userDao;
     public User findUser(String username,String password){
         return userDao.findUser(username,password);
     }

     public int findUserCount(String username,String password){
         return userDao.findUserCount(username,password);
     }

     public boolean insertUser(User user){
         return userDao.insertUser(user);
     }
 }

2.4 修改UserController.java的userIndex方法：

 @RequestMapping(value = "/index.html", method = RequestMethod.POST)
     public ModelAndView userIndex(String username, String password) {
         if (StringUtil.isEmpty(username) || StringUtil.isEmpty(password)) {
             logger.error("用户名或密码为空");
             ModelAndView modelAndView = new ModelAndView("/index");
             modelAndView.addObject("error", "用户名或密码为空！");
             return modelAndView;
         }

 //        int count = userService.findUserCount(username,password);
         User user = userService.findUser(username, password);
         if (user == null) {
             logger.info("用户名或密码错误");
             ModelAndView modelAndView = new ModelAndView("/index");
             modelAndView.addObject("username", username);
             modelAndView.addObject("error", "用户：" + username + "不存在或用户密码错误！");
             return modelAndView;
         }
         ModelAndView mav = new ModelAndView("success");
         mav.addObject("username", username);
         mav.addObject("password", password);
         logger.info("username : " + username + ", password : " + password);
         return mav;
     }

这样就实现了登录的简单流程。