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Package sns.team6.util;
Import java.sql.Connection;
Import Java.sql.DriverManager;
Import java.sql.PreparedStatement;
Import Java.sql.ResultSet;
Import java.sql.SQLException;
/**
* Link the Database tool class
*
* @author Xu Rui
*
*/
public class DBHelper {
MySQL Drive path
Private static final String Driver = "Com.mysql.jdbc.Driver";
Connection path for database
Private static final String URL = "JDBC:MYSQL://LOCALHOST:3306/SNSTEAM6";
/**
* Objects that connect to the database
*
* @return
*/
public static Connection getconnection () {
Connection conn = null;
try {
Class.forName (driver);
conn = drivermanager.getconnection (URL, "root", "root");
catch (Exception e) {
E.printstacktrace ();
}
Return conn;
}
/**
* Close the Open resource
*
* @param Conn
* @param PST
* @param rst
*/
public static void Closeinfo (Connection conn, PreparedStatement PST,
ResultSet rst) {
try {
if (rst!= null) {
Rst.close ();
rst = null;
}
if (PST!= null) {
Pst.close ();
PST = NULL;
}
IF (conn!= null) {
Conn.close ();
conn = null;
}
catch (Exception e) {
E.printstacktrace ();
}
}
/**
* Get result set object
*
* @param sql
* @param params
* @return
*/
public static ResultSet ResultSet (String sql, object[] params) {
The linked object of the database
Connection conn = null;
The Operation object of the database
PreparedStatement PST = NULL;
Result Object
ResultSet rst = null;
try {
The linked object of the database
conn = Dbhelper.getconnection ();
The Operation object of the database
PST = conn.preparestatement (SQL);
Determine if there are parameters
if (params!= null && params.length > 0) {
for (int i = 0; i < params.length; i++) {
Assigning a value to an Action object
Pst.setobject (i + 1, params[i]);
}
}
Get the result object
rst = Pst.executequery ();
catch (SQLException e) {
rst = null;
E.printstacktrace ();
}
return rst;
}
/**
* Get the added result object
*
* @param sql
* @param params
* @return
*/
public static Boolean result (String sql, object[] params) {
Boolean flag = false;
The linked object of the database
Connection conn = null;
The Operation object of the database
PreparedStatement PST = NULL;
try {
The linked object of the database
conn = Dbhelper.getconnection ();
The Operation object of the database
PST = conn.preparestatement (SQL);
Determine if there are parameters
if (params!= null && params.length > 0) {
for (int i = 0; i < params.length; i++) {
Assigning a value to an Action object
Pst.setobject (i + 1, params[i]);
}
}
Gets the result object, which is the int type, indicating the number of rows executed successfully
int row = Pst.executeupdate ();
if (Row > 0) {
If greater than 0 indicates successful execution
Flag = true;
}
catch (SQLException e) {
Flag = false;
E.printstacktrace ();
}
return flag;
}
}
Example
Import Java.sql.DriverManager;
Import Java.sql.ResultSet;
Import java.sql.SQLException;
Import java.sql.Connection;
Import java.sql.Statement;
public class Mysqldemo {
public static void Main (string[] args) throws Exception {
Connection conn = null;
String SQL;
MySQL jdbc URL write way: jdbc:mysql://host Name: Connection port/database name? parameter = value
Avoid Chinese garbled to specify Useunicode and characterencoding
To create a database on the database management system before performing the database operation, the name is set by itself.
The following statement must first create the Javademo database
String url = "Jdbc:mysql://localhost:3306/javademo?"
+ "User=root&password=root&useunicode=true&characterencoding=utf8";
try {
The reason to use the following statement is to use the MySQL driver, so we're going to drive it,
It can be loaded through class.forname, or it can be driven by initialization, and the following three forms can be
Class.forName ("Com.mysql.jdbc.Driver")//dynamic load MySQL Driver
Or
Com.mysql.jdbc.Driver Driver = new Com.mysql.jdbc.Driver ();
Or
New Com.mysql.jdbc.Driver ();
System.out.println ("Successfully loaded MySQL driver");
A connection represents a database connection
conn = drivermanager.getconnection (URL);
Statement contains many methods, such as executeupdate can be inserted, updated and deleted, etc.
Statement stmt = Conn.createstatement ();
sql = "CREATE TABLE student (no char (), name varchar (), primary key (No))";
int result = stmt.executeupdate (SQL);//Executeupdate statement returns an affected number of rows, if return-1 is not successful
If (Result!=-1) {
SYSTEM.OUT.PRINTLN ("Create data table succeeded");
sql = "INSERT into student (No,name) VALUES (' 2012001 ', ' Tao Weiki ')";
result = Stmt.executeupdate (SQL);
sql = "INSERT into student (No,name) VALUES (' 2012002 ', ' Zhou Xiaojun ')";
result = Stmt.executeupdate (SQL);
sql = "SELECT * from student";
ResultSet rs = stmt.executequery (sql);//ExecuteQuery Returns a collection of results, otherwise null values are returned
System.out.println ("School number \ t name");
while (Rs.next ()) {
System.out
. println (rs.getstring (1) + "T" + rs.getstring (2));/Enter if the type of int returned can be getint ()
}
}
catch (SQLException e) {
System.out.println ("MySQL operation Error");
E.printstacktrace ();
catch (Exception e) {
E.printstacktrace ();
finally {
Conn.close ();
}
}
} |
