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Spring | JdbcTemplate & Mysql

2006-09-24 00:06 274 查看

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-----张汉东

Spring提供的JDBC抽象框架core、datasource、object和support四个不同的包组成.
org.springframework.jdbc.core包里定义了提供核心功能的类,其中包含了一个用语JdbcTemplate的DAO基础类.我就是用这个基础类来实战连接Mysql数据库的.
对于没有Spring的日子的代码,这样的代码用来把记录集存储到一个对象中:
Object vo = new Object();
vo.setXX(rs.getXType(fieldName1));
vo.setYY(rs.getYType(fieldName2));
在Spring里,提供了这样一个接口RowMapper,其方法是public Object mapRow(ResultSet rs,int index),来完成这样的工作.
对于:
while(rs.next()) {
Object vo = new Object();
vo.setXX(rs.getXType(fieldName1)); vo.setYY(rs.getYType(fieldName2));
……
results.add(vo);
}
Spring中用new RowMapperResultReader(new RowMapper())来取代.
这样,JDBC中的查询过程,就被如下一句话所取代:
JdbcTemplate.query(sql,params,new RowMapperResultReader(new RowMapper()));
这个JdbcTemplate的query()方法封装了对JDBC底层API的调用,以及一些回调方法. 回调方法也是Spring框架的一种基本方法.
程序中使用了DAO来封装了对数据库的操作……JdbcTemplate的使用需要有一个DataSource的支持,所以在配置文件中,我们首先要配置一个Spring的DriverManagerDataSource,然后将这个DataSource配置到JdbcTemplate里.接着将JdbcTemplate配置到DAO层.最后将DAO配置到Model层:
具体的代码如下:(连接数据库为Mysql)
一.cn.zhd.DAO层
UserDAO接口:

package cn.zhd.DAO;
import cn.zhd.Model.User;
import java.util.List;
public interface UserDAO {
public void selectWithTemp();
public List select(String where);
public void update(String how);
public void insert(User u);
public User selectById(String id);
public void insertBatchData(final List<User> user);
}

DAO接口实现类

package cn.zhd.DAO.Imp;

import cn.zhd.DAO.UserDAO;
import cn.zhd.Model.User;
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;

public class UserDAOImp implements UserDAO{
private JdbcTemplate jt;

public JdbcTemplate getJt() {
return jt;
}

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

//Inner Class提供一个RresultSet中的row的映射对象
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";
System.out.println("Id"+"/t"+"Name"+"/t"+"Password");
jt.query(sql,new RowCallbackHandler(){//一个实现了回调接口的类
//此方法为回调方法,每读取一行ResultSet被调用一次,它采用的是Statement, not a PreparedStatement
public void processRow(ResultSet rs) throws SQLException{

System.out.println(rs.getString("Id")+"/t"+rs.getString("Name")+"/t"+rs.getString("Password"));
}

});

}
//多行查询
public List select(String where){
List list=null;
String sql="select * from admin"+”/t”+where;//这里不能少”/t”,教训
list=jt.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};
jt.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"));
System.out.println(rs.getString("Name")+"/t"+rs.getString("Password"));
}
});
return u;
}
public void update(String how){
String sql=how;
jt.update(sql);
}
//将插入数据封装为一个对象作为参数传递给JdbcTemplate
public void insert(User u){
String sql="insert into admin(id,name,password) values(null,?,?)";
Object[] params=new Object[]{u.getName(),u.getPassword()};
jt.update(sql,params);
}
//批量插入数据
public void insertBatchData(final List<User> user){
String sql="insert into admin(id,name,password) values(null,?,?)";
BatchPreparedStatementSetter setter=new BatchPreparedStatementSetter(){
public int getBatchSize(){
return user.size();
}
// 给PreparedStatement 设置value
public void setValues(PreparedStatement ps,int index){
User u= user.get(index);
try{
ps.setString(1,u.getName());
ps.setString(2,u.getPassword());

}catch(SQLException e){
e.printStackTrace();
}
}
};
jt.batchUpdate(sql, setter);
}
}

二Model层

cn.zhd.Model.User.java

package cn.zhd.Model;
import java.util.List;
import cn.zhd.DAO.UserDAO;

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);
}
//得到查询结果
public void selectWithTemp(){
dao.selectWithTemp();
}
//按id查询
public User selectById(String id){
return dao.selectById(id);
}
//批量插入数据
public void insertBatchData(final List<User> user){
dao.insertBatchData(user);
}
}

三.xml配置文件beans.xml

<?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="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName">
<value>com.mysql.jdbc.Driver</value>
</property>

<property name="url">
<value>jdbc:mysql:///students</value>
</property>

<property name="username">
<value>root</value>
</property>

<property name="password">
<value></value>
</property>
</bean>

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

<bean id="userDAO" class="cn.zhd.DAO.Imp.UserDAOImp">
<property name="jt">
<ref bean="jdbcTemplate" />
</property>
</bean>

<bean id="user" class="cn.zhd.Model.User">
<property name="dao">
<ref bean="userDAO"/>
</property>
<property name="name">
<value>zjd</value>
</property>
<property name="password">
<value>888</value>
</property>
</bean>
</beans>

四.测试类 JavaTest.java

package cn.zhd.Model;

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;

public class UserTest {
public static void main(String []args){
// User u=new User("zjd","888");
//批量插入数据
List<User> u = new ArrayList<User>();
u.add(new User("haha","123"));
u.add(new User("hoho","234"));
u.add(new User("zhansan","345"));
u.add(new User("lisi","456"));
u.add(new User("maqi","577"));
u.add(new User("wo","899"));
u.add(new User("admin","haha"));
u.add(new User("fdsdf","675"));
u.add(new User("werwr","89"));
Resource resource=new ClassPathResource("beans.xml");
BeanFactory factory = new XmlBeanFactory(resource);
User user = (User) factory.getBean("user");
// user.insert();
// user.update("update admin set name='zbj' where id=2");
user.insertBatchData(u);
// user.selectWithTemp();
// user.selectById("2");
// user.getInfo("2");
}
}

虽然做完了,但是感觉对Spring的理解还是不够深入,慢慢学习吧…

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Spring | JdbcTemplate &amp; Mysql

Spring | JdbcTemplate & Mysql