dbutil 的使用方法

public static void main(String[] args) {
TestHandler t = new TestHandler();
try {
t.test9();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void test1() throws SQLException {
String sql = "select * from product where id = ? and count = ? ";
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
List<Product> list = qr.query(sql, new BeanListHandler<>(Product.class));
for (Product product : list) {
System.out.println(product.getName());
}
}
//适合取一条数据
public void test2() throws SQLException {
String sql = "select * from product where id = ? and count = ? ";
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
Object[] query = qr.query(sql, new ArrayHandler());
List<Object[]> query2 = qr.query(sql, new ArrayListHandler());
}
//取一条数据变为实体类对象
public void test3() throws SQLException {
String sql = "select * from product where id = ? and count = ? ";
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
Product query = qr.query(sql, new BeanHandler<>(Product.class));
}
//取一列数据
public void test4() throws SQLException {
String sql = "select * from product ";
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
List<Object> query = qr.query(sql, new ColumnListHandler<>(1));
for (Object object : query) {
System.out.println(object);
}
}
//取多条数据,每一条数据是小map,把小map放到大map中
//key是你指定的字段值
//大map的key是某列数列,小map的key是表的列名
public void test5() throws SQLException {
String sql = "select * from product ";
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
Map<Object, Map<String, Object>> query = qr.query(sql, new KeyedHandler<>(2));
for(Map.Entry<Object, Map<String, Object>> m : query.entrySet()) {
for(Map.Entry<String, Object> mm : m.getValue().entrySet()) {
System.out.println(mm.getKey()+"\t"+mm.getValue());
}
}
}

//update

public void test6() throws SQLException {
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
String sql = "insert into product values(12,'电视21',10,100) ";
int row = qr.update(sql);
}
public void test7() throws SQLException {
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
String sql = "update product set name = ? where id = ?";
int row = qr.update(sql,"你好",12);
}
public void test8() throws SQLException {
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
String sql = "delete from product where id = ? ";
int row = qr.update(sql,12);
}

public void test9()throws SQLException {
QueryRunner qr = new QueryRunner(C3P0Util.getCpds());
String sql ="select count(*) from product";
Object query = qr.query(sql,new ScalarHandler<>());
Integer count = Integer.valueOf(query.toString());
System.out.println(count);
}