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Spring:JdbcTemplate使用指南

 小朋 2009-02-18

前言:

本文指在介紹Spring框架中的JdbcTemplate類的使用方法,涉及基本的Spring反轉(zhuǎn)控制的使用方法和JDBC的基本概念。目標(biāo)是使讀者能夠?qū)?/span>JdbcTemplate快速地掌握和使用。

 

       準(zhǔn)備:

1. Spring的基本概念

       Spring框架核心的思想就是建立一個Java對象的大工廠,用戶只要給工廠一個指令,工廠就能將用戶需要的對象根據(jù)配置文件組裝好返還給用戶。用戶需要做的許多工作則可以寫成簡單的配置文件。

       2. 丑陋的JDBC代碼

Connection con= null;

PreparedStatement pStmt=null;

ResultSet rs = null;

try{          

            con = ods.getConnection();

            String sql = "select * from admin";

            pStmt=con.prepareStatement(sql);           

            rs=pStmt.executeQuery();

            while(rs.next())

            {            }

}

catch(Exception ex) {

try{

         con.rollback();

    }catch(SQLException sqlex){

          sqlex.printStackTrace(System.out);

     }

     ex.printStackTrace();

}finally{

   try{

            rs.close();

            pStmt.close();

            con.close();

   }catch(Exception e){e.printStackTrace();}

}

 

 

       以上是常見的JDBC代碼,簡單的select語句也需要冗長的出錯處理,并且每個函數(shù)都不斷地重復(fù)同樣的代碼。

 

       3. JdbcTemplate的作用

       JdbcTemplate正是為了減少上述繁瑣的代碼而設(shè)計出來的。它是對JDBC的一種封裝,抽象我們常用的一些方法。Simple and Stupid就是它的目標(biāo)。下面是完成了剛才JDBC代碼同樣功能的JdbcTemplate的代碼:

String sql = "select * from admin";

jdbcTemplate.query(sql,new RowCallbackHandler() {

         public void processRow(ResultSet rs) throws SQLException {   

                }

            } );

 

 

       環(huán)境搭建:

1. 數(shù)據(jù)庫的配置

       本文使用Oracle數(shù)據(jù)庫,新建表admin

create table admin (
       ID number(
10) primary key,
       NAME varchar2(
64),
       PASSWORD varchar2(
64)
)

 

 

       2. Spring配置

       JdbcTemplate的使用需要有DataSource的支持,所以在配置文件中,我們首先要配置一個OracleDataSource,然后在將這個DataSource配置到JdbcTemplate里。接著將JdbcTemplate配置進DAO層,最后將DAO配置進Model層。簡要的關(guān)系如下:

 

      

模型層 : User

數(shù)據(jù)訪問層:UserDAO

JdbcTemplate

OracleDataSource

<!--[if !vml]--><!--[endif]-->

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"

    "http://www./dtd/spring-beans.dtd">

<beans>

    <bean id="dataSource" class="oracle.jdbc.pool.OracleDataSource">

        <property name="URL">

            <value>jdbc:oracle:thin:root/123@localhost:1521/XE</value>

        </property>

    </bean>

   

    <bean id="jdbcTemplate"

class="org.springframework.jdbc.core.JdbcTemplate">

        <property name="dataSource"><ref bean="dataSource"/></property>

    </bean>

 

    <bean id="userDAO" class="DAO.Imp.UserDAOImp">

        <property name="jdbcTemplate">

<ref bean="jdbcTemplate" />

</property>

    </bean>

   

    <bean id="user" class="Model.User">

        <property name="dao"><ref bean="userDAO"/></property>

    </bean>

</beans>

 

       3. 環(huán)境配置, 如圖:

       <!--[if !vml]--><!--[endif]-->

 

使用方法:

<!--[if !supportLists]-->1.       <!--[endif]-->查找

多行查詢:

class UserRowMapper implements RowMapper {

        public Object mapRow(ResultSet rs,int index) throws SQLException

        {

            User u = new User();

            u.setId(rs.getString("ID"));

            u.setName(rs.getString("Name"));

            u.setPassword(rs.getString("Password"));

            return u;

        }

    }

public List select(String where)

    {

        List list;       

        String sql = "select * from admin "+where;       

        list = jdbcTemplate.query(sql,new RowMapperResultReader(new UserRowMapper()));

        return list;

    }

 

 

 

List最終返回的是滿足條件的User隊列。

 

單行查詢:

public User selectById(String id){

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

    final User u = new User();

    final Object[] params = new Object[] {id};

    jdbcTemplate.query(sql, params, new RowCallbackHandler(){

                        public void processRow(ResultSet rs) throws SQLException {

                                 u.setId(rs.getString("ID"));

                                 u.setName(rs.getString("NAME"));

                                 u.setPassword(rs.getString("PASSWORD"));

                        }                     

    });         

    return u;

}

 

 

 

<!--[if !supportLists]-->2.       <!--[endif]-->插入

public void insert(User u)

{

     String sql = "insert into admin (ID,NAME,PASSWORD) values (admin_id_seq.nextval,?,?)";

     Object[] params = new Object[] {

                                                u.getName(),

                                                u.getPassword() };

     jdbcTemplate.update(sql,params);

 }

 

admin_id_seq.nextvalOracle設(shè)置好的序列,問號“?”被params里的數(shù)據(jù)依次替代,最終執(zhí)行sql。

 

<!--[if !supportLists]-->3.       <!--[endif]-->修改

非常簡單:

public void update(String how)

{

        jdbcTemplate.update(how);

    }

 

 

源代碼:

User.class:

package Model;

 

import java.util.List;

import DAO.UserDAO;

/**

 *  Model

 *

 *

 * @author 李嘉陵

 * @since 2006-4-30 12:10:30

 * @version 0.10a

 **/

 

public class User {

    private String name;

    private String id;

    private String password;

    private UserDAO dao;

   

    public User()

    {

      

    }

   

    public User(String name, String password)

    {

       this.name = name;

       this.password = password;

    }

   

    public void setDao(UserDAO dao)

    {

        this.dao = dao;

    }

    public String getId() {

        return id;

    }

   

    public void setId(String id) {

        this.id = id;

    }

   

    public String getName() {

        return name;

    }

   

    public void setName(String name) {

        this.name = name;

    }

   

    public String getPassword() {

        return password;

    }

   

    public void setPassword(String password) {

        this.password = password;

    }

   

    public void getInfo(String id)

    {

        List list = dao.select("where id="+id);

        User u = (User) list.get(0);

       

        this.id=id;

        this.name = u.getName();

        this.password = u.getPassword();

       

    }

   

    public void insert()

    {

        dao.insert(this);

    }

   

    public void update(String how)

    {

        dao.update(how);

    }

   

    public void update()

    {

        dao.update("update admin set name='"+name+"', password='"+password+"' where id="+id);

    }

   

    public List selectWithTemp(String where)

    {

        return dao.select(where);

    }

   

    public void selectWithTemp()

    {

        dao.selectWithTemp();

    }

   

    public User selectById(String id)

    {

       return dao.selectById(id);

    }

    

    public void insertUsers(List users)

    {

       dao.insertUsers(users);

    }

}

 

 

UserDAO.class :

package DAO;

 

import java.util.List;

 

import Model.User;

 

/**

 * DAO層接口

 *

 *

 * @author 李嘉陵

 * @since 2006-4-30 8:40:56

 * @version 0.10a

 **/

 

public interface UserDAO {

    public void select();

    public void test();

    public void selectWithTemp();

    public List select(String where);

    public void update(String how);

    public void insert(User u);

    public User selectById(String id);

    public int[] insertUsers(final List users);

   

}

 

UserDAOImp.class:

package DAO.Imp;

 

 

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.List;

 

import org.springframework.jdbc.core.BatchPreparedStatementSetter;

import org.springframework.jdbc.core.JdbcTemplate;

import org.springframework.jdbc.core.RowCallbackHandler;

import org.springframework.jdbc.core.RowMapper;

import org.springframework.jdbc.core.RowMapperResultReader;

 

import DAO.UserDAO;

import Model.User;

 

/**

 *  DAO層的實現(xiàn)

 *

 *

 * @author 李嘉陵

 * @since 2006-4-30 8:41:26

 * @version 0.10a

 **/

 

public class UserDAOImp implements UserDAO{

   

    private JdbcTemplate jdbcTemplate;

   

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate)

    {

        this.jdbcTemplate = jdbcTemplate;

    }

   

    class UserRowMapper implements RowMapper

    {

        public Object mapRow(ResultSet rs,int index) throws SQLException

        {

            User u = new User();

            u.setId(rs.getString("ID"));

            u.setName(rs.getString("Name"));

            u.setPassword(rs.getString("Password"));

 

            return u;

        }

    }

   

    public void selectWithTemp()

    {

        String sql = "select * from admin";

              

        jdbcTemplate.query(sql,new RowCallbackHandler() {

                public void processRow(ResultSet rs) throws SQLException {

                System.out.println("ID: "+rs.getString("ID")+"   Name: "+rs.getString("name"));

                }

            } );

 

    }

   

    public List select(String where)

    {

        List list;

        String sql = "select * from admin "+where;

        list = jdbcTemplate.query(sql,new RowMapperResultReader(new UserRowMapper()));

        return list;

    }

   

    public User selectById(String id)

    {

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

       final User u = new User();

       final Object[] params = new Object[] {id};

      

       jdbcTemplate.query(sql,params, new RowCallbackHandler(){

                         public void processRow(ResultSet rs) throws SQLException {

                                   u.setId(rs.getString("ID"));

                                   u.setName(rs.getString("NAME"));

                                   u.setPassword(rs.getString("PASSWORD"));

                         }

       });

      

       return u;

    }

   

    public void update(String how)

    {

        String sql = how;

        jdbcTemplate.update(sql);

    }

   

    public void insert(User u)

    {

        String sql = "insert into admin (ID,NAME,PASSWORD) values (admin_id_seq.nextval,?,?)";

        Object[] params = new Object[] {

                                                   u.getName(),

                                                   u.getPassword()};

        jdbcTemplate.update(sql,params);

    }

  

}

 

 

UserAction.class:

//測試類

public class UserAction {

    public static void main(String[] args)

    {

        Resource resource=new ClassPathResource("beans.xml");

        BeanFactory factory = new XmlBeanFactory(resource);       

        User user = (User) factory.getBean("user");   

       

        user.selectWithTemp();

    }

}

 

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