//使用SimpleTemplate
public class UserDaoSpringImpl implementsUserDao{
SimpleJdbcTemplate simple=newSimpleJdbcTemplate(JdbcUtils.getDataSource());
//增加
public void addUser(User user){
String sql="insert into user(name.birthday)vlaues(:name,:birthday)";
SqlParameterSource param=newBeanPropertySqlParameterSource(user);
KeyHolder keyHolder=new GeneratedKeyHolder();
this.simpleJdbcTemplate.getNamedParameterJdbcOperations().update(sql,param,keyHolder);
user.setId(keyHolder.getKey().initValue());
}
//删除
public void delete(User user){
String sql="delete from user where id=?";
this.simpleJdbcTemplate.update(sql,user.getId());
}
//查询
publci User findUser(String loginName,String password){
String sql="select id,name from user where name=?";
returnthis.simpleJdbcTemplate.queryForObject(sql,ParameterizedBanPropertyRowMapper.newInstance(User.class),loginName);
}
//查询
publci User getUser(int userId){
String sql="select id,name from user where id=?";
returnthis.simpleJdbcTemplate.queryForObject(sql,ParameterizedBanPropertyRowMapper.newInstance(User.class),userId);
}
//更新
public void update(User user){
String sql="update user set name=?,birthday=? where id=?";
this.simpleJdbcTemplate.update(sql,user.getName(),use.getBirthday(),user.getId())
//或者
String sql="update user set name=:name,birthday=:birthday whereid=:id";
this.simpleJdbcTemplate.update(sql,newBeanPropertySqlParameterSource(user));//BeanPropertySqlParameterSource方法中的:id必须和类的属性名一样
}
}
一、Spring JDBC 概述
Spring提供了一个强有力的模板类JdbcTemplate简化JDBC操作,DataSource,JdbcTemplate都可以以Bean的方式定义在想xml配置文件,JdbcTemplate创建只需注入一个DataSource,应用程序Dao层只需要继承JdbcDaoSupport,或者注入JdbcTemplate,便可以获取JdbcTemplate,JdbcTemplate是一个线程安全的类,多个Dao可以注入一个JdbcTemplate;
Xml代码
<!-- Oracle数据源 -->
<bean id="dataSource"class="org.apache.commons.dbcp.BasicDataSource"destroy-method="close">
<property name="driverClassName"value="oracle.jdbc.driver.OracleDriver"/>
<property name="url"value="jdbc:oracle:thin:@oracle.devcake.co.uk:1521:INTL"/>
<property name="username"value="sa"/>
<property name="password"value=""/>
</bean>
<bean id="jdbcTemplate"class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource"ref="dataSource"/>
</bean>
<bean id="customerDao" class="JdbcCustomerDao">
<property name="dataSource"ref="dataSource"/>
</bean>
<!-- Oracle数据源 -->
<bean id="dataSource"class="org.apache.commons.dbcp.BasicDataSource"destroy-method="close">
<property name="driverClassName"value="oracle.jdbc.driver.OracleDriver"/>
<property name="url"value="jdbc:oracle:thin:@oracle.devcake.co.uk:1521:INTL"/>
<property name="username"value="sa"/>
<property name="password"value=""/>
</bean>
<bean id="jdbcTemplate"class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource"ref="dataSource"/>
</bean>
<bean id="customerDao" class="JdbcCustomerDao">
<property name="dataSource"ref="dataSource"/>
</bean>
然后将jdbcTemplate对象注入自定义的Dao、或者继承JdbcDaoSupport,例如:
Java代码
public class JdbcCustomerDao extends JdbcDaoSupport implementsCustomerDao {
}
public class JdbcCustomerDao implements CustomerDao{
private JdbcTemplatejdbcTemplate
public void setJdbcTemplate()JdbcTemplatejdbcTemplate{
this.jdbcTemplate=jdbcTemplate
}
}
public class JdbcCustomerDao extends JdbcDaoSupport implementsCustomerDao {
}
public class JdbcCustomerDao implements CustomerDao {
private JdbcTemplate jdbcTemplate
public void setJdbcTemplate()JdbcTemplate jdbcTemplate{
this.jdbcTemplate=jdbcTemplate
}
}
二、 JdbcTemplate 提供以下主要方法简化JDBC操作:
2.1、List query(String sql,Ojbect[] args,RowMapper rowMapper)
说明:常用的查询,sql待执行的sql语句,args是sql语句的参数,rowMapper负责将每一行记录转化为java对象存放在list,并最终返回,例如:
Java代码
public List<Book>queryByAuthor(String author){
String sql = "select * from book whereauthor=?";
Collection c =getJdoTemplate().find(sql,
new Object[] { author },newBookRowMapper());
List<Book> books = newArrayList<Book>();
books.addAll(c);
return books;
}
class BookRowMapper implementsRowMapper{
public Object mapRow(ResultSet res, int index) throws SQLException{
Book book = new Book();
book.setId(rs.getInt("id"));
//省略set
return book;
}
}
public List<Book>queryByAuthor(String author) {
String sql = "select * from book where author=?";
Collection c = getJdoTemplate().find(sql,
new Object[] { author },new BookRowMapper());
List<Book> books = newArrayList<Book>();
books.addAll(c);
return books;
}
class BookRowMapper implements RowMapper{
public Object mapRow(ResultSet res, int index) throws SQLException{
Book book = new Book();
book.setId(rs.getInt("id"));
//省略set
return book;
}
}
更新、删除、其他查询操作类似,举例如下,详细细节请参考spring api:
Java代码
//返回值为一个长整形
public long getAverageAge(){
returngetJdbcTemplate().queryForLong("SELECT AVG(age) FROMemployee");
}
//返回一个整数
public int getTotalNumberOfEmployees(){
returngetJdbcTemplate().queryForInt("SELECT COUNT(0) FROMemployees");
}
//更新操作
this.jdbcTemplate.update(
"insert into t_actor (first_name, surname) values (?,?)",
new Object[] {"Leonor", "Watling"});
//返回值为一个长整形
public long getAverageAge() {
returngetJdbcTemplate().queryForLong("SELECT AVG(age) FROMemployee");
}
//返回一个整数
public int getTotalNumberOfEmployees() {
returngetJdbcTemplate().queryForInt("SELECT COUNT(0) FROMemployees");
}
//更新操作
this.jdbcTemplate.update(
"insert into t_actor (first_name, surname) values (?, ?)",
new Object[] {"Leonor", "Watling"});
2.2、spring 2.5新功能,另类的jdbcORM:BeanPropertyRowMapper
上面我们检索时必须实现RowMapper,将结果集转化为java对象。Spring2.5简化了这一操作,使得我们不必再实现RowMapper,实现此功能的俩个神奇东东便是:ParameterizedRowMapper,ParameterizedBeanPropertyRowMapper,貌似通过java反射机制实现了将resultset字段映射到java对象,但是数据表的列必须和java对象的属性对应,没有研究源码,有点类似于apache的BeanUtil,不知为何这部分在spring开发参考手册没有,难道不是经典。
Java代码
//使用ParameterizedBeanPropertyRowMapper
@SuppressWarnings({"unchecked"})
publicList<Customer> getAll(){
return getJdbcTemplate().query("select * from t_customer",ParameterizedBeanPropertyRowMapper.newInstance(Customer.class));
}
//使用BeanPropertyRowMapper
@SuppressWarnings({"unchecked"})
publicList<Customer> getAll(){
return getJdbcTemplate().query("select * from t_customer", newBeanPropertyRowMapper(Customer.class));
}
//使用ParameterizedBeanPropertyRowMapper
@SuppressWarnings({"unchecked"})
publicList<Customer> getAll() {
return getJdbcTemplate().query("select * from t_customer",ParameterizedBeanPropertyRowMapper.newInstance(Customer.class));
}
//使用BeanPropertyRowMapper
@SuppressWarnings({"unchecked"})
publicList<Customer> getAll() {
return getJdbcTemplate().query("select * from t_customer", newBeanPropertyRowMapper(Customer.class));
}
注意:ParameterizedBeanPropertyRowMapper是BeanPropertyRowMapper子类。另外表的字段名称必须和实体类的成员变量名称一致;
2.3、spring之JDBC批量操作
jdbcTemplate.batchUpdate(final String[] sql) ,API解释:Issue multipleSQL updates on a single JDBC Statement usingbatching,翻译过来大致为:解决多个sql的插入、更新、删除操作在一个Statement中。性能一般。
jdbcTemplate.batchUpdate(String sql, finalBatchPreparedStatementSetterpss),类似于JDBC的PreparedStatement,性能较上着有所提高。
我们举例说明如何使用,示例如下:
Java代码
final int count = 2000;
finalList<String> firstNames = newArrayList<String>(count);
finalList<String> lastNames = newArrayList<String>(count);
for (int i =0; i < count; i++) {
firstNames.add("First Name " + i);
lastNames.add("Last Name " + i);
}
jdbcTemplate.batchUpdate(
"insert into customer (id, first_name, last_name, last_login,comments) values (?, ?, ?, ?, ?)",
new BatchPreparedStatementSetter() {
//为prepared statement设置参数。这个方法将在整个过程中被调用的次数
public void setValues(PreparedStatement ps, int i) throwsSQLException {
ps.setLong(1, i + 10);
ps.setString(2, firstNames.get(i));
ps.setString(3, lastNames.get(i));
ps.setNull(4, Types.TIMESTAMP);
ps.setNull(5, Types.CLOB);
}
//返回更新的结果集条数
public int getBatchSize() {
return count;
}
});
}
BatchSqlUpdate类是SqlUpdate的子类,适用于插入、删除、更新批量操作,内部使用PreparedStatement,所以效率很高,批量语句达到设定的batchSize,或者手动调用flush才会执行批量操作。注意:此类是非线程安全的,必须为每个使用者创建一个实例,或者在同一个线程中使用前调用reset。
下面我们举例说明如何使用BatchSqlUpdate,来执行批量操作。示例如下:
Java代码
class BatchInsert extends BatchSqlUpdate{
private static final String SQL = "insert intot_customer (id, first_name, last_name, last_login,"
+ "comments) values (?, ?, ?, ?,null)";
BatchInsert(DataSource dataSource){
super(dataSource, SQL);
declareParameter(newSqlParameter(Types.INTEGER));
declareParameter(newSqlParameter(Types.VARCHAR));
declareParameter(newSqlParameter(Types.VARCHAR));
declareParameter(newSqlParameter(Types.TIMESTAMP));
setBatchSize(10);
}
}
class BatchInsert extends BatchSqlUpdate {
private static final String SQL = "insert intot_customer (id, first_name, last_name, last_login, "
+ "comments) values (?, ?, ?, ?, null)";
BatchInsert(DataSource dataSource) {
super(dataSource, SQL);
declareParameter(new SqlParameter(Types.INTEGER));
declareParameter(new SqlParameter(Types.VARCHAR));
declareParameter(new SqlParameter(Types.VARCHAR));
declareParameter(new SqlParameter(Types.TIMESTAMP));
setBatchSize(10);
}
}
Java代码
int count = 5000;
for (int i =0; i < count; i++) {
batchInsert.update(new Object[] { i + 100L, "a" + i, "b" + i, null});
}
至此,springJDBC主要的应用基本上都简单罗列一番,抛砖引玉,希望有独特见解的拍砖