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

 1 jdbc.driver=com.mysql.jdbc.Driver
 2 jdbc.url=jdbc:mysql://localhost:3306/sampledb
 3 jdbc.username=root
 4 jdbc.password=123456
 5 jdbc.initialSize=5
 6 jdbc.maxActive=10
 7 jdbc.minIdle=5
 8 jdbc.maxIdle=10
 9 jdbc.timeBetweenEvictionRunsMillis=3600000
10 jdbc.minEvictableIdleTimeMillis=3600000
11 jdbc.testOnBorrow=true
12 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：

 1 public class User {
 2     private Long id;
 3     private String username;
 4     private String email;
 5     private String password;
 6     private Long credit;
 7     private Date lastVisitTime;
 8     private String lastVisitIp;
 9     //setter、getter
10 }

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：

 1 public User findUser(final String username, final String password) {
 2         String sql = "select id,user_name, credit from t_user_info where user_name = ? and password = ?";
 3         User user = null;
 4         try {
 5             RowMapper<User> rm = ParameterizedBeanPropertyRowMapper.newInstance(User.class);
 6             user = (User) jdbcTemplate.queryForObject(sql, new Object[]{username, password}, rm);
 7         }catch (Exception e){
 8             e.printStackTrace();
 9         }
10         return user;
11     }

2.3 添加UserService.java类，代码如下：

 1 @Service("userService")
 2 public class UserService {
 3     @Autowired
 4     UserDao userDao;
 5     public User findUser(String username,String password){
 6         return userDao.findUser(username,password);
 7     }
 8
 9     public int findUserCount(String username,String password){
10         return userDao.findUserCount(username,password);
11     }
12
13     public boolean insertUser(User user){
14         return userDao.insertUser(user);
15     }
16 }

2.4 修改UserController.java的userIndex方法：

 1 @RequestMapping(value = "/index.html", method = RequestMethod.POST)
 2     public ModelAndView userIndex(String username, String password) {
 3         if (StringUtil.isEmpty(username) || StringUtil.isEmpty(password)) {
 4             logger.error("用户名或密码为空");
 5             ModelAndView modelAndView = new ModelAndView("/index");
 6             modelAndView.addObject("error", "用户名或密码为空！");
 7             return modelAndView;
 8         }
 9
10 //        int count = userService.findUserCount(username,password);
11         User user = userService.findUser(username, password);
12         if (user == null) {
13             logger.info("用户名或密码错误");
14             ModelAndView modelAndView = new ModelAndView("/index");
15             modelAndView.addObject("username", username);
16             modelAndView.addObject("error", "用户：" + username + "不存在或用户密码错误！");
17             return modelAndView;
18         }
19         ModelAndView mav = new ModelAndView("success");
20         mav.addObject("username", username);
21         mav.addObject("password", password);
22         logger.info("username : " + username + ", password : " + password);
23         return mav;
24     }

这样就实现了登录的简单流程。