Using Reflection to design Basedao

Package Com.dao.impl;

Import Java.lang.reflect.Field;
Import java.sql.Connection;
Import Java.sql.DriverManager;
Import java.sql.PreparedStatement;
Import Java.sql.ResultSet;
Import Java.sql.ResultSetMetaData;
Import java.sql.SQLException;
Import java.util.ArrayList;

Import java.util.List;
/**
* All DAO's parent classes
* date:1111 Year November 11
* @description:
*/
public class Basedao {

protected Connection con;

protected PreparedStatement PS;

protected ResultSet RS;


public void SetConnection () {

try {
Class.forName ("Org.gjt.mm.mysql.Driver");
con = drivermanager.getconnection
("Jdbc:mysql://localhost:3306/product?characterencoding=utf-8", "root", "123456");

catch (ClassNotFoundException e) {
TODO auto-generated Catch block
E.printstacktrace ();
catch (SQLException e) {
TODO auto-generated Catch block
E.printstacktrace ();
}


}


public void CloseConnection () {

try {

if (Rs!= null) {
Rs.close ();
}
if (PS!= null) {
Ps.close ();
}
if (con!= null) {
Con.close ();
}

catch (Exception e) {
E.printstacktrace ();
}

}

/**
* @Title: UpdateData
* @Description: TODO Update data
* @param: @param SQL SQL statements
* @param: @param valueArray Value List
* @return: void
* @throws
*/
public void UpdateData (String sql,object[] valueArray) {

This.setconnection ();

try {
Execute SQL statement
PS = con.preparestatement (SQL);
Fill placeholder
for (int i=0;i<valuearray.length;i++) {

Ps.setobject (i+1, valuearray[i]);

}
Update Database
Ps.executeupdate ();

catch (SQLException e) {
TODO auto-generated Catch block
E.printstacktrace ();
}finally{
This.closeconnection ();
}

}


/**
* @Title: FindData
* @Description: TODO query data
* @param: @param SQL query SQL statement
* @param: @param valueArray Value List
* @param: @param the type of object in the Beanclass collection
* @param: @return Collection of query results
* @return: List
* @throws
*/
Public List FindData (String sql,object[] Valuearray,class beanclass) {

List List = new ArrayList ();

This.setconnection ();

try {
PS = con.preparestatement (SQL);

if (ValueArray!= null) {

for (int i=0;i<valuearray.length;i++) {

Ps.setobject (i+1, valuearray[i]);
}

}

rs = Ps.executequery ();
To get the result set of the examination object
ResultSetMetaData rm = Rs.getmetadata ();
The number of columns that get the query in the result set
int columnCount = Rm.getcolumncount ();

System.out.println (columncount+ "" +rm.getcolumnname (1));

while (Rs.next ()) {

Object beanobj = Beanclass.newinstance ();

There are several columns, loops several times
for (int i=1;i<=columncount;i++) {
Get the column name of the query column
String columnName = Rm.getcolumnname (i);
Get the value of the column name
Object valueobj = Rs.getobject (columnName);

Property object that corresponds to the property name
Field field = Beanclass.getdeclaredfield (ColumnName);
Remove access modifier check
Field.setaccessible (TRUE);
Fills a value with the specified property of an object
Field.set (Beanobj, valueobj);

}
List.add (Beanobj);

}

while (Rs.next ()) {
Generate new entity objects at once per loop
Object beanobj = Beanclass.newinstance ();
//
//
//
If you query only some of the fields, you throw a lot of exceptions that are inefficient
Get all Attributes List
field[] fs = Beanclass.getdeclaredfields ();
//
for (Field Field:fs) {
//
try{
Get Property name
String fieldName = Field.getname ();
Gets the value of the specified column from the result set
Object valueobj = Rs.getobject (fieldName);
//
Remove access modifier check
Field.setaccessible (TRUE);
//
//
Sets the specified property value
Field.set (Beanobj, valueobj);
//
}catch (Exception e) {
//
Continue
//
//     }
//    }



List.add (Beanobj);
//
//   }



catch (Exception e) {

E.printstacktrace ();
}finally{
This.closeconnection ();
}




return list;

}



public static void Main (string[] args) {
//
Basedao dao = new Basedao ();
Dao.setconnection ();
System.out.println (Dao.con);
//
// }


}