QueryRunner的使用

欢迎使用Markdown编辑器写博客

public class JdbcUtil {
private static ComboPooledDataSource dataSource =new ComboPooledDataSource();
public static ComboPooledDataSource getDataSource()
{
return dataSource;
}

}

src目录下c3p0-config.xml

从数据库中取count(*)数据

1 int topicNum=0;
2 QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
3 String sql =”select count(*) from topic where type_id= ? order by time desc”;
4 Object[] params={typeId};
5 topicNum=(int)(long) runner.query(sql,new ScalarHandler(),params);
6 return topicNum;

取一条数据 其中表的字段名字和类的名字要对应相同

1 Topic newlyTopic=null;
2 QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
3 String sql =”select * from topic where type_id= ? order by time desc”;
4 Object[] params={typeId};
5 newlyTopic= runner.query(sql,new BeanHandler(Topic.class),params);
6 return newlyTopic;

取集合数据List<>返回 其中表的字段名字和类的名字要对应相同

1 List topicList=new ArrayList();
2 QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
3 String sql =”select * from topic where type_id= ? order by time desc”;
4 Object[] params={typeId};
5 topicList=runner.query(sql, new BeanListHandler(Topic.class),params);
6 return topicList;
插入

复制代码
1 QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
2 String sql =”insert into topic(name,author,content,time,type_id) values(?,?,?,?,?)”;
3 Object[] params={topic.getName(),topic.getAuthor(),topic.getContent(),topic.getTime(),topic.getTypeId()};
4 try {
5 //事务开始
6 runner.update(sql,params);
7 //事务提交
8 } catch (SQLException e) {
9 e.printStackTrace();
10 //事务回滚
11 throw e;
12 }
复制代码
更新

复制代码
1 QueryRunner runner= new QueryRunner(JdbcUtil.getDataSource());
2 String sql =”update topic set name=? , content=? , time=? where id= ?”;
3 Object[] params={topic.getName(),topic.getContent(),topic.getTime(),topic.getId()};
4 try {
5 //事务开始
6 runner.update(sql,params);
7 //事务提交
8 } catch (SQLException e) {
9 e.printStackTrace();
10 //事务回滚
11 throw e;
12 }