问题:有时候数据库连接失败,程序好像还继续往下运行,会报个空指针异常,现在就是怎么处理这个数据库连接出的问题,报错直接捕获,程序不往下运行,不就不会包那个空指针异常。。代码如下,帮修改下下。很感谢!public List selectMark(Integer ) {
jdbc = new JDBConnection();
connection = jdbc.connection;
List list = new ArrayList();
GoodsForm goods = null;
String sql = "";
try {
if(==0||==1||==null){
sql = "select * from tb_goods where spsd=1 order by id DESC";
}else if(==2){
sql = "select * from tb_goods where ="++" and spsd=1 and sysdate between begin_time and end_time order by id DESC";
}else if(==3){
sql = "select * from tb_goods where ="++" and spsd=1 order by id DESC";
}else if(==4){
sql = "select * from tb_goods where ="++" and spsd=1 order by id DESC";
}
ps = connection.prepareStatement(sql);
//ps.setInt(1, .intValue());
ResultSet rs = ps.executeQuery();
while (rs.next()) {
goods = new GoodsForm();
goods.setId(Integer.valueOf(rs.getString(1)));
goods.setBig(Integer.valueOf(rs.getString(2)));
goods.setSmall(Integer.valueOf(rs.getString(3)));
goods.setName(rs.getString(4));
goods.setFrom(rs.getString(5));
goods.setIntroduce(rs.getString(6));
goods.setCreaTime(rs.getString(7));
goods.setNowPrice(Float.valueOf(rs.getString(8)));
goods.setFreePrice(Float.valueOf(rs.getString(9)));
goods.setNumber(Integer.valueOf(rs.getString(10)));
goods.setPriture(rs.getString(11));
goods.setMark(Integer.valueOf(rs.getString(12)));
goods.setSpsd(Integer.valueOf(rs.getString(13)));
if (rs.getString(14) != null) {
goods.setSalesNumber(Integer.valueOf(rs.getString(14)));
} else {
goods.setSalesNumber(0);
}
if (rs.getString(15) != null) {
goods.setSpdm(Integer.valueOf(rs.getString(15)));
} else {
goods.setSpdm(0);
}
goods.setSpec(rs.getString(16));
goods.setUnit(rs.getString(17));
goods.setBarCode(rs.getString(18));
goods.setPurchase_price(rs.getString(19));
goods.setSpecialOffer(rs.getString(20));
list.add(goods);
}
rs.close();
ps.close();
connection.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
return list;
}
jdbc = new JDBConnection();
connection = jdbc.connection;
List list = new ArrayList();
GoodsForm goods = null;
String sql = "";
try {
if(==0||==1||==null){
sql = "select * from tb_goods where spsd=1 order by id DESC";
}else if(==2){
sql = "select * from tb_goods where ="++" and spsd=1 and sysdate between begin_time and end_time order by id DESC";
}else if(==3){
sql = "select * from tb_goods where ="++" and spsd=1 order by id DESC";
}else if(==4){
sql = "select * from tb_goods where ="++" and spsd=1 order by id DESC";
}
ps = connection.prepareStatement(sql);
//ps.setInt(1, .intValue());
ResultSet rs = ps.executeQuery();
while (rs.next()) {
goods = new GoodsForm();
goods.setId(Integer.valueOf(rs.getString(1)));
goods.setBig(Integer.valueOf(rs.getString(2)));
goods.setSmall(Integer.valueOf(rs.getString(3)));
goods.setName(rs.getString(4));
goods.setFrom(rs.getString(5));
goods.setIntroduce(rs.getString(6));
goods.setCreaTime(rs.getString(7));
goods.setNowPrice(Float.valueOf(rs.getString(8)));
goods.setFreePrice(Float.valueOf(rs.getString(9)));
goods.setNumber(Integer.valueOf(rs.getString(10)));
goods.setPriture(rs.getString(11));
goods.setMark(Integer.valueOf(rs.getString(12)));
goods.setSpsd(Integer.valueOf(rs.getString(13)));
if (rs.getString(14) != null) {
goods.setSalesNumber(Integer.valueOf(rs.getString(14)));
} else {
goods.setSalesNumber(0);
}
if (rs.getString(15) != null) {
goods.setSpdm(Integer.valueOf(rs.getString(15)));
} else {
goods.setSpdm(0);
}
goods.setSpec(rs.getString(16));
goods.setUnit(rs.getString(17));
goods.setBarCode(rs.getString(18));
goods.setPurchase_price(rs.getString(19));
goods.setSpecialOffer(rs.getString(20));
list.add(goods);
}
rs.close();
ps.close();
connection.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
return list;
}
想理清楚你想干嘛
1、数据库连接异常了,就自然查不出数据,那么,你想让前台知道然后处理还是你后台自己处理
2、后台处理:既然出错了,就告诉前台,后台出问题,该怎么怎么怎么
前台处理:后台出了错,就把异常一直往外面抛,直到某个前台页面,可以处理的(WEB应用中,不现实)