获取参数的元数据信息

public class parameterMedaData {

public static void main(String[] args) {
//创建sql语句
String sql = "select * from user where id >?";
//创建一个数组
Object obj[] = new Object[]{3};
read(sql,obj);
}

static void read(String sql,Object obj[]){
Connection conn=null;
PreparedStatement ps =null;
ResultSet rs = null;
JDBCUtils utils =JDBCUtils.getInstance();
try {
conn=utils.getConnection();
//获取数据库元数据
DatabaseMetaData dmd = conn.getMetaData();
System.out.println(dmd.getDatabaseProductName());//获取数据库名
ps = conn.prepareStatement(sql);
//获取参数的元数据信息
ParameterMetaData pmd = ps.getParameterMetaData();
//获取参数个数，即问号的个数
int count = pmd.getParameterCount();
for(int i=1;i<=count;i++){
//将数组里的元素赋值给对应的问号
ps.setObject(i, obj[i-1]);
}
rs = ps.executeQuery();
while(rs.next()){
System.out.print(rs.getObject("username"));
}
} catch (SQLException e) {
e.printStackTrace();
}

}
}