mysql中如何将字符串类型（java）转换为日期数据类型存储？

Question

Im getting an error message while inserting values from the form. Error is Column count doesn't match value count at raw 1 . My 5th string value must be stored as date data type in sql.

String s1=this.txtUsername.getText();
String s2=this.txtPassword.getText();
String s3=this.txtName.getText();
String s4=this.txtAddress.getText();
String s5=this.txtContractEndDetails.getText();


         connection getcon = new connection();
         Connection conn;


    try{
        conn=getcon.creatConnection();
        Statement stmt=conn.createStatement();

        stmt.executeUpdate("insert into TravelGuide(username,password,name,address,contract_end_date)values ('"+s1+"','"+s2+"','"+s3+"','"+s4+"'+'"+s5+"')");



        }
    catch(Exception ex){
        JOptionPane.showMessageDialog(PanelTG, ex.getMessage(),"Error Occured",2);
    }

Here's my relevant table for SQL query.

  create table TravelGuide(
  username char(20),
  password char(20),
  name varchar(100),
  address varchar(150),
  contract_end_date date,
  constraint TravelGuide_PK primary key(username)
  );

edited

Im confused about

preparedStatement("insert into TravelGuide (username,password,name,address,contract_end_date) values (?, ?, ?, ?, ?)");

Could u explain this furthermore..

Is this right? The codes which are inside ** marks are giving errors illegal start of expression and cannot find symbol.. Please help me..

try {
    conn=getcon.creatConnection();

    **String sql="insert into TravelGuide("+"username,"+"password,,"+,"name,"+"address,"+"contract_end_date)"+"values(?,?,?,?,?)";**
    PreparedStatement stmt = conn.**preparedStatement**(sql);
    java.sql.Date dtValue = java.sql.Date.valueOf(s5); 

    stmt.setString(1, s1);
    stmt.setString(2, s2);
    stmt.setString(3, s3);
    stmt.setString(4, s4);
    stmt.setDate(5, dtValue);
    stmt.executeUpdate();                
}

Answer 1

Inside the try , do this instead:

conn = getconn.creatConnection();
PreparedStatement stmt = conn.prepareStatement("insert into TravelGuide (username,password,name,address,contract_end_date) values (?, ?, ?, ?, ?)");

java.sql.Date date = someFunctionToConvertYourDateStringToADate(s5);

stmt.setString(1, s1);
stmt.setString(2, s2);
stmt.setString(3, s3);
stmt.setString(4, s4);
stmt.setDate(5, date);
stmt.executeUpdate();

[and so on]

That way you are protected from SQL injection attacks and you don't have to worry about how to massage your string into a format a specific database requires for a date column. The JDBC driver will handle that for you, given a java.sql.Date object.

Answer 2

stmt.executeUpdate("insert into TravelGuide(username,password,name,address,contract_end_date)values ('"+s1+"','"+s2+"','"+s3+"','"+s4+"'**+**'"+s5+"')");

why +,i think i should be,