? Spring-JdbcTemplate 总结

1． 查询单个对象:

a)????? 基本类型

================================================

下面两个方法主要适用于静态sql

◆???? public Object queryForObject(String sql, RowMapper rowMapper)

◆???? public Object queryForObject(String sql, Class requiredType)

注意：requiredType 只能是基本类型的class,只针对基本类型有效

◆???? public Object queryForObject(String sql, Object[] args, Class requiredType)

◆???? public Object queryForObject(String sql, Object[] args, RowMapper rowMapper)

◆???? public Object queryForObject(String sql, Object[] args, int [] argTypes, Class requiredType)

注：其中argTypes 可以使用java.sql.Types常量类中的常量值

◆???? public Object queryForObject(String sql, Object[] args, int [] argTypes, RowMapper rowMapper)

注： rowMapper是一个回调接口

以下主要用于查询数值对象

◆???? public int queryForInt(String sql, Object[] args)

◆???? public long queryForLong(String sql, Object[] args)

==================================================

下面的方法将返回的各个列封装成map对象，key为列名，value为列值.只能一行数据，不能返回多行数据.

◆???? public Map queryForMap(String sql, Object[] args)

b)????? 引用类型

◆???? public Object queryForObject(String sql, RowMapper rowMapper)

◆???? public Object queryForObject(String sql, Object[] args, RowMapper rowMapper)

◆???? public Map queryForMap(String sql, Object[] args)

2． 查询多个对象

a)????? 基本类型:

◆???? public List queryForList(String sql, Object[] args)

注：返回的list的每个元素都是一个map对象,该map对象封装了一行数据且只有一行数据，包括要查询的列字段

b)????? 引用类型: ???

◆???? public List queryForList(String sql, Object[] args)

??????? Iterator iter =? this .jdbcTemplate.queryForList(sql,new Object[]{}).iterator();

??????? List list = new ArrayList();

??????? while (iter.hasNext()){

??????????? User user = new User();

??????????? Map map = (Map) iter.next();

??????????? Set<Entry<String, String>> set = map.entrySet();

??????????? Iterator<Entry<String, String>> iter2 = set.iterator();

??????????? Entry<String, String> entry = iter2.next();

??????????? user.setUsername(entry.getValue());

??????????? entry = iter2.next();

??????????