Spring 学习 （六）Spring 整合JDBC

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如何整合的？
其实就是Spring中提供了一个可以操作数据库的对象，对象封装了jdbc技术
JDBCTemplate jdbc模板对象
具体用法其实和DBUtils一样
直接放案例

bean

public class User {
   private Integer id ;
   private String name ;

   public Integer getId() {
      return id;
   }
   public void setId(Integer id) {
      this.id = id;
   }
   public String getName() {
      return name;
   }
   public void setName(String name) {
      this.name = name;
   }

}

接口

 */
public interface UserDao {

    //增
    void save ( User u ) ;

    //删除
    void delete (Integer id ) ;

    //改
    void update ( User u ) ;

    //查
    User getById ( Integer id ) ;

    //查
    int getTotalCount () ;

    //查
    List <User> getAll () ;

}

实现
基本包含dao常用操作

public class UserDaoImpl implements UserDao {

    private JdbcTemplate jt ;


    public JdbcTemplate getJt() {
        return jt;
    }

    public void setJt(JdbcTemplate jt) {
        this.jt = jt;
    }

    /*
     * @see com.study.spring.UserDao#save(com.study.spring.User)
     */
    @Override
    public void save(User u) {
        String sql = "insert into user values (null , ?)" ;

        jt.update(sql, u.getName()) ;

    }

    /*
     * @see com.study.spring.UserDao#delete(java.lang.Integer)
     */
    @Override
    public void delete(Integer id) {
        String sql = "delete from user where id = ?" ;

        jt.update(sql, id) ;
    }

    /*
     * @see com.study.spring.UserDao#update(com.study.spring.User)
     */
    @Override
    public void update(User u) {
        String sql = "update user set name = ? where id = ?" ;

        jt.update(sql, u.getName() , u.getId()) ;
    }

    /*
     * @see com.study.spring.UserDao#getById(java.lang.Integer)
     */
    @Override
    public User getById(Integer id) {

        String sql = "select * from User where id = ?" ;

        return jt.queryForObject(sql, new RowMapper <User> ()
                {
                    @Override //result 里存放每次遍历的结果  args 存放索引
                    public User mapRow(ResultSet result , int args ) throws SQLException {

                        User user = new User () ;
                        user.setId( result.getInt("id") );
                        user.setName( result.getString("name") );

                        return user ;
                    }
                } , id ) ;
    }

    /*
     * @see com.study.spring.UserDao#getTotalCount()
     */
    @Override
    public int getTotalCount() {

        String sql = "select count(*) from user" ;

        //当查询结果是值类型可以使用此方法，要手动指定值类型
        return jt.queryForObject( sql , Integer.class ) ;
    }

    /*
     * @see com.study.spring.UserDao#getAll()
     */
    @Override
    public List<User> getAll() {

        String sql = "select * from user " ;

        List <User> list =  jt.query( sql , new RowMapper <User> ()
                {
                    @Override
                    public User mapRow(ResultSet result, int args) throws SQLException {

                        User user = new User () ;
                        user.setId( result.getInt("id") );
                        user.setName( result.getString("name") );

                        return user ;
                    }

                }) ;

        return list ;
    }

}

xml

<?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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    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.xsd
         http://www.springframework.org/schema/aop
         http://www.springframework.org/schema/aop/spring-aop.xsd
         http://www.springframework.org/schema/tx
         http://www.springframework.org/schema/tx/spring-tx.xsd">

   <!-- 将数据库连接池交由Spring管理 -->
   <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
      <property name="jdbcUrl" value="jdbc:mysql:///Demo"></property>
      <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
      <property name="user" value="root"></property>
      <property name="password" value="zh123456"></property>
   </bean>

   <!-- jdbcTemplate -->
   <bean name="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
      <property name="dataSource" ref="dataSource"></property>
   </bean>

   <!-- dao -->
   <bean name="userDao" class="com.study.spring.UserDaoImpl">
      <property name="jt" ref="jdbcTemplate"></property>
   </bean>


</beans>

接下来介绍一个扩招 JDBCDaoSupport
继承此类后，一个类可以从其父类获得JDBCTemplate对象（父类根据数据库连接池类型创建的）

public class UserDaoImpl extends JdbcDaoSupport implements UserDao {


    /*
     * @see com.study.spring.UserDao#save(com.study.spring.User)
     */
    @Override
    public void save(User u) {
        String sql = "insert into user values (null , ?)" ;

        super.getJdbcTemplate().update(sql, u.getName()) ;

    }

    /*
     * @see com.study.spring.UserDao#delete(java.lang.Integer)
     */
    @Override
    public void delete(Integer id) {
        String sql = "delete from user where id = ?" ;

        super.getJdbcTemplate().update(sql, id) ;
    }

    /*
     * @see com.study.spring.UserDao#update(com.study.spring.User)
     */
    @Override
    public void update(User u) {
        String sql = "update user set name = ? where id = ?" ;

        super.getJdbcTemplate().update(sql, u.getName() , u.getId()) ;
    }

    /*
     * @see com.study.spring.UserDao#getById(java.lang.Integer)
     */
    @Override
    public User getById(Integer id) {

        String sql = "select * from User where id = ?" ;

        return super.getJdbcTemplate().queryForObject(sql, new RowMapper <User> ()
                {
                    @Override //result 里存放每次遍历的结果  args 存放索引
                    public User mapRow(ResultSet result , int args ) throws SQLException {

                        User user = new User () ;
                        user.setId( result.getInt("id") );
                        user.setName( result.getString("name") );

                        return user ;
                    }
                } , id ) ;
    }

    /*
     * @see com.study.spring.UserDao#getTotalCount()
     */
    @Override
    public int getTotalCount() {

        String sql = "select count(*) from user" ;

        //当查询结果是值类型可以使用此方法，要手动指定值类型
        return super.getJdbcTemplate().queryForObject( sql , Integer.class ) ;
    }

    /*
     * @see com.study.spring.UserDao#getAll()
     */
    @Override
    public List<User> getAll() {

        String sql = "select * from user " ;

        List <User> list =  super.getJdbcTemplate().query( sql , new RowMapper <User> ()
                {
                    @Override
                    public User mapRow(ResultSet result, int args) throws SQLException {

                        User user = new User () ;
                        user.setId( result.getInt("id") );
                        user.setName( result.getString("name") );

                        return user ;
                    }

                }) ;

        return list ;
    }

}

xml

<?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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    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.xsd
         http://www.springframework.org/schema/aop
         http://www.springframework.org/schema/aop/spring-aop.xsd
         http://www.springframework.org/schema/tx
         http://www.springframework.org/schema/tx/spring-tx.xsd">

   <!-- 将数据库连接池交由Spring管理 -->
   <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
      <property name="jdbcUrl" value="jdbc:mysql:///Demo"></property>
      <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
      <property name="user" value="root"></property>
      <property name="password" value="zh123456"></property>
   </bean>

   <!-- dao -->
   <bean name="userDao" class="com.study.spring.UserDaoImpl">
      <property name="dataSource" ref="dataSource"></property>
   </bean>


</beans>

读取properties配置

有时候数据库链接地址 用户 密码经常来回变动，一变动就要从Spring配置文件中找到此配置在修改，比较麻烦，所以为了方便修改可以将这些信息放到properties文件中

写properties文件时建议在key前面加上前缀，以免和Spring中其他关键字冲突（不想写也行）
注意：properties中不要有空格，否则运行慢+报错！！！

properties

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jdbcUrl=jdbc:mysql:///Demo
driverClass=com.mysql.jdbc.Driver
user=root
password=xxxxxxxx

用${key}取值
bean.xml

<?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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    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.xsd
         http://www.springframework.org/schema/aop
         http://www.springframework.org/schema/aop/spring-aop.xsd
         http://www.springframework.org/schema/tx
         http://www.springframework.org/schema/tx/spring-tx.xsd">

   <!-- 指定Spring读取DB.properties配置 -->
   <context:property-placeholder location="classpath:DB.properties"/>

   <!-- 将数据库连接池交由Spring管理 -->
   <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
      <property name="jdbcUrl" value="${jdbcUrl}"></property>
      <property name="driverClass" value="${driverClass}"></property>
      <property name="user" value="${user}"></property>
      <property name="password" value="${password}"></property>
   </bean>

   <!-- dao -->
   <bean name="userDao" class="com.study.spring.UserDaoImpl">
      <property name="dataSource" ref="dataSource"></property>
   </bean>


</beans>