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[Java教程]使用Jdbc Template的基本操作步骤


 1.appliactionContext.

<?     ="http://www.springframework.org/schema/p"     ="http://www.w3.org/2001/     xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">      <!--数据源的配置 -->   <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">     <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>     <property name="url" value="jdbc:mysql:///spring"></property>     <property name="username" value="root"></property>     <property name="password" value=""></property>   </bean>           <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">     <property name="dataSource" ref="dataSource"></property>   </bean>        <bean id="userDao" class="cn.happy.impl.UserDAOImpl">    <property name="jdbcTemplate" ref="jdbcTemplate"></property>   </bean> </beans>

  2.接口:IUserDAO.java

 public interface IUserDAO {    public void addUser(User user);   public void deleteUser(int id);   public void updateUser(User user);   public String searchUserName(int id);     public User searchUser(int id);     public List<User> findAll(); }

3.接口实现类:UserDAOImpl.java

Spring提供了JdbcDaoSupport支持类,所有DAO继承这个类,就会自动获得JdbcTemplate(前提是注入DataSource)。

<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">     <property name="dataSource" ref="dataSource"></property>   </bean>        <bean id="userDao" class="cn.happy.impl.UserDAOImpl">     <property name="jdbcTemplate" ref="jdbcTemplate"></property>   </bean>

JdbcTemplate主要提供下列方法:

  1、execute方法:可以用于执行任何SQL语句,一般用于执行DDL语句;

  2、update方法及batchUpdate方法:update方法用于执行新增、修改、删除等语句;batchUpdate方法用于执行批处理相关语句;

  3、query方法及queryForXXX方法:用于执行查询相关语句;

  4、call方法:用于执行存储过程、函数相关语句。

public class UserDAOImpl extends JdbcDaoSupport implements IUserDAO {   public void addUser(User user) {     String sql = "insert into user values(?,?,?)";     this.getJdbcTemplate().update(sql, user.getId(), user.getUsername(),         user.getPassword());   }   public void deleteUser(int id) {     String sql = "delete from user where id=?";     this.getJdbcTemplate().update(sql, id);   }   public void updateUser(User user) {     String sql = "update user set username=?,password=? where id=?";     this.getJdbcTemplate().update(sql, user.getUsername(),         user.getPassword(), user.getId());   }   public String searchUserName(int id) {// 简单查询,按照ID查询,返回字符串     String sql = "select username from user where id=?";     // 返回类型为String(String.class)     return this.getJdbcTemplate().queryForObject(sql, String.class, id);   }   public List<User> findAll() {// 复杂查询返回List集合     String sql = "select * from user";     return this.getJdbcTemplate().query(sql, new UserRowMapper());   }   public User searchUser(int id) {     String sql="select * from user where id=?";     return this.getJdbcTemplate().queryForObject(sql, new UserRowMapper(), id);   }   class UserRowMapper implements RowMapper<User> {      //rs为返回结果集,以每行为单位封装着     public User mapRow(ResultSet rs, int rowNum) throws SQLException {         User user = new User();       user.setId(rs.getInt("id"));       user.setUsername(rs.getString("username"));       user.setPassword(rs.getString("password"));       return user;     }   } }

4.测试类:UserTest.java

public class UserTest {     @Test//增   public void demo1(){     User user=new User();     user.setId(3);     user.setUsername("admin");     user.setPassword("123456");         ApplicationContext applicationContext=new ClassPath);     IUserDAO dao=(IUserDAO) applicationContext.getBean("userDao");     dao.addUser(user);       }     @Test//改   public void demo2(){     User user=new User();     user.setId(1);     user.setUsername("admin");    user.setPassword("admin");         ApplicationContext applicationContext=new ClassPath);     IUserDAO dao=(IUserDAO) applicationContext.getBean("userDao");     dao.updateUser(user);   }     @Test//删   public void demo3(){     ApplicationContext applicationContext=new ClassPath);     IUserDAO dao=(IUserDAO) applicationContext.getBean("userDao");     dao.deleteUser(3);   }     @Test//查(简单查询,返回字符串)   public void demo4(){     ApplicationContext applicationContext=new ClassPath);     IUserDAO dao=(IUserDAO) applicationContext.getBean("userDao");     String name=dao.searchUserName(1);     System.out.println(name);   }     @Test//查(简单查询,返回对象)   public void demo5(){     ApplicationContext applicationContext=new ClassPath);     IUserDAO dao=(IUserDAO) applicationContext.getBean("userDao");     User user=dao.searchUser(1);     System.out.println(user.getUsername());   }     @Test//查(复杂查询,返回对象集合)   public void demo6(){     ApplicationContext applicationContext=new ClassPath);     IUserDAO dao=(IUserDAO) applicationContext.getBean("userDao");     List<User> users=dao.findAll();     System.out.println(users.size());   }      }