从jdbc中检索数据

Question

I have a string array which holds the name of 500 stocks. Now i have a table in my mysql database which holds the symbol for more than 1000 stocks alonwith their name. What i would like to do is retrieve the symbol of those 500 stocks from the table i have. I have tried the following code

Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection("jdbc:mysql//localhost/mydatabase","user","pass");
PreparedStatement stmt = conn.prepareStatement("SELECT (NAME) FROM stocks1 WHERE FULLNAME =?"); 
for(int i1=0;i1<i;i1++)
{   
  stmt.setString(1, name[i1]); 


  stmt.addBatch(); 
} 
ResultSet t=stmt.executeQuery(); 
while(t.next())
  System.out.println(t.getString("NAME"));

But it doesnt work. Nothing is printed. I think i am making a mistake in stmt.addBatch(). Also if i wanted the name[i1] to be follwed by a wildcard charcter(%) how would i do this.

Answer 1

You could create a table for the stocks in your string array and do a join with your stocks1 table.

Let's say the table for your arraystocks is named stocksperuser with one column FULLNAME the code looks like this:

Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection("jdbc:mysql//localhost/mydatabase","user","pass");
PreparedStatement stmt = conn.prepareStatement("SELECT NAME FROM stocks1 WHERE FULLNAME is in (SELECT FULLNAME FROM arraystocks)"); 
ResultSet t=stmt.executeQuery(); 
while(t.next()) {
    System.out.println(t.getString("NAME"));
}

Answer 2

For including wildcard, you can do as shown below.

In your select statement remove = and add LIKE

PreparedStatement stmt = conn.prepareStatement("SELECT (NAME) FROM stocks1 WHERE FULLNAME LIKE ?");   

add % in the setString method.

ps.setString(1, name[i1]+ "%");

Also , for empty rows issue , please check if both the comparison column's case are the same,either they should be in upper or in lower. If its not , then you can convert while comparing as shown below.

SELECT (NAME) FROM stocks1 WHERE upper(FULLNAME) LIKE ?   

ps.setString(1, upper(name[i1])+ "%");