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[zt]JdbcTemplate使用指南

key words:Spring,jdbcTemplate

注：因為Spring是以后的一個趨勢，Hibernate的集成已經很好了，對于單獨的jdbc的操作用DBUtils感覺已經沒有什么必要，不如全部轉到Spring的jdbc支持，從成本來考慮似乎更合適。

本文轉自這里

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 反轉控制的使用方法和 JDBC 的基本概念。目標是使讀者能夠對 JdbcTemplate 快速地掌握和使用。

?????? 準備：

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，并且每個函數都不斷地重復同樣的代碼。

?????? 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。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 {???

??????????????? }

??????????? } );

?????? 環境搭建：

1. 數據庫的配置

?????? 本文使用 Oracle 數據庫，新建表 admin ：

create table admin (
?????? IDnumber( 10 ) primarykey,
?????? NAMEvarchar2( 64 ),
?????? PASSWORDvarchar2( 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。簡要的關系如下：

??????

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

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

??? "http://www.springframework.org/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">

</property>

??? </bean>

???

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

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

??? </bean>

</beans>

?????? 3. 環境配置，如圖：

??????

使用方法：

1.?????? 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;

}

2.?????? 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.nextval 為 Oracle 設置好的序列，問號“ ? ”被 params 里的數據依次替代，最終執行 sql 。

3.?????? 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 層

?* @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

?* @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();

??? }

}

posted on 2006-10-16 16:28 Alex 閱讀(2749) 評論(0) 編輯收藏所屬分類: Spring

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