SSM学习04spring的数据库开发之query（）方法

继续从上一个进行了insert update delete的地方开始用query进行find和list操作

在Dao接口中再写两个方法：

 1 package com.zyk.database;
 2 
 3 import java.util.List;
 4 
 5 public interface AccountDao {
 6     public int add(Account account);
 7     public int update(Account account);
 8     public int delete(int id);
 9     public Account find(int id);
10     public List<Account> listAll();
11 }

在DaoImpl中实现这两个方法：

 1 @Override
 2     public Account find(int id) {
 3         String sql="select * from account where id=?";
 4         RowMapper<Account> rowMapper=new BeanPropertyRowMapper<Account>(Account.class);
 5         return this.jdbcTemplate.queryForObject(sql, rowMapper,id);
 6     }
 7 
 8     @Override
 9     public List<Account> listAll() {
10         // TODO Auto-generated method stub
11         String sql="select * from account";
12         RowMapper<Account> rowMapper=new BeanPropertyRowMapper<Account>(Account.class);
13         return this.jdbcTemplate.query(sql, rowMapper);
14     }

FindTest进行测试查找数据库：

 1 package com.zyk.database;
 2 
 3 
 4 import org.springframework.context.ApplicationContext;
 5 import org.springframework.context.support.ClassPathXmlApplicationContext;
 6 
 7 public class FindTest {
 8 
 9     public static void main(String[] args) {
10         // TODO Auto-generated method stub
11         ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
12         AccountDao accountDao= (AccountDao)applicationContext.getBean("accountDao");
13         Account account=accountDao.find(2);
14         System.out.println(account);
15         
16     }
17 
18 }

截图：

ListAll进行显示：

 1 package com.zyk.database;
 2 
 3 import java.util.List;
 4 
 5 import org.springframework.context.ApplicationContext;
 6 import org.springframework.context.support.ClassPathXmlApplicationContext;
 7 
 8 public class ListAllTest {
 9 
10     public static void main(String[] args) {
11         // TODO Auto-generated method stub
12         ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
13         AccountDao accountDao=(AccountDao)applicationContext.getBean("accountDao");
14         List<Account> accounts=accountDao.listAll();
15         for(Account act: accounts) {
16             System.out.println(act);
17         }
18     }
19 
20 }

截图：

总结：

RowMapper<Account> rowMapper=new BeanPropertyRowMapper<Account>(Account.class)
是创建一个新的BeanPropertyRowMapper对象。

 return this.jdbcTemplate.queryForObject(sql, rowMapper,id);
将id绑定到sql语句中，并通过rowMapper返回一个object类型的单行记录。