javaweb中mysql数据库连接步骤方法及其实例

/*协议：子协议://主机:端口/数据库名*/
Stringurl="jdbc:mysql://localhost:3306/jdbctest";
//mysql数据库的用户名与密码，安装时自己设置，一般默认为root
Stringuser="root";
Stringpassword="root";
Connectionconnection=null;
Statementstatement=null;
ResultSetresultSet=null;
try{
//1.加载驱动//com.mysql.jdbc.Driver
/*
*DriverManager.registerDriver(new
*Driver());用这种方法会加载两次驱动，也就是说会创建两个drive对象
*/
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接
connection=DriverManager.getConnection(url,user,password);
//3.获取用于向数据库发送SQL的Statement对象
statement=connection.createStatement();
//4.执行sql,获取数据
resultSet=statement.executeQuery("SELECT*FROMusers;");
//解析数据
while(resultSet.next()){
intid=resultSet.getInt("id");
Stringname=resultSet.getString("name");
Stringpsd=resultSet.getString("password");
Stringemail=resultSet.getString("email");
Stringbirthday=resultSet.getString("birthday");
System.out.println(id+""+name+""+psd+""+email
+""+birthday);
}
}catch(ClassNotFoundExceptione){
e.printStackTrace();
}catch(SQLExceptione){
e.printStackTrace();
}finally{
//5.关闭连接，释放资源
if(resultSet!=null){
try{
resultSet.close();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
resultSet=null;
}
if(statement!=null){
try{
statement.close();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
statement=null;
}
if(connection!=null){
try{
connection.close();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
connection=null;
}
/* 协议：子协议://主机:端口/数据库名 */
String url = "jdbc:mysql://localhost:3306/jdbctest";
// mysql数据库的用户名与密码，安装时自己设置，一般默认为root
String user = "root";
String password = "root";
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
  // 1.加载驱动//com.mysql.jdbc.Driver
  /*
   * DriverManager.registerDriver(new
   * Driver());用这种方法会加载两次驱动，也就是说会创建两个drive对象
   */
  Class.forName("com.mysql.jdbc.Driver");
  // 2.获取连接
  connection = DriverManager.getConnection(url, user, password);
  // 3.获取用于向数据库发送SQL的Statement对象
  statement = connection.createStatement();
  // 4.执行sql,获取数据
  resultSet = statement.executeQuery("SELECT * FROM users;");
  // 解析数据
  while (resultSet.next()) {
int id = resultSet.getInt("id");
String name = resultSet.getString("name");
String psd = resultSet.getString("password");
String email = resultSet.getString("email");
String birthday = resultSet.getString("birthday");
System.out.println(id + " " + name + " " + psd + " " + email
+ " " + birthday);
  }
} catch (ClassNotFoundException e) {
  e.printStackTrace();
} catch (SQLException e) {
  e.printStackTrace();
} finally { 
    //5.关闭连接，释放资源
  if (resultSet != null) {
try {
  resultSet.close();
} catch (SQLException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
}
resultSet = null;
  }
  if (statement != null) {
try {
  statement.close();
} catch (SQLException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
}
statement = null;
  }
  if (connection != null) {
try {
  connection.close();
} catch (SQLException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
}
connection = null;
  }
}

url=jdbc:mysql://localhost:3306/jdbctest
username=root
password=root
driver=com.mysql.jdbc.Driver

importjava.io.IOException;
importjava.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.ResultSet;
importjava.sql.SQLException;
importjava.sql.Statement;
importjava.util.Properties; 
publicclassJdbcUtil{
//私有静态变量，用以读取配置文件
privatestaticPropertiesconfig=newProperties();
static{
try{
//配置资源文件
config.load(JdbcUtil.class.getClassLoader().getResourceAsStream("db.properties"));
//加载驱动
Class.forName(config.getProperty("driver"));
}catch(IOExceptione){
e.printStackTrace();
}catch(ClassNotFoundExceptione){
e.printStackTrace();
}
}
publicstaticConnectiongetConnection(){
Connectionconnection=null;
try{
connection=DriverManager.getConnection(config.getProperty("url"),config.getProperty("username"),config.getProperty("password"));
}catch(SQLExceptione){
e.printStackTrace();
}
returnconnection;
}
//用以关闭连接，释放资源
publicstaticvoidreleaseConn(Connectionconnection,Statementstatement,
ResultSetresultSet){
if(resultSet!=null){
try{
resultSet.close();
}catch(SQLExceptione){
e.printStackTrace();
}
resultSet=null;
}
if(statement!=null){
try{
statement.close();
}catch(SQLExceptione){
e.printStackTrace();
}
statement=null;
}
if(connection!=null){
try{
connection.close();
}catch(SQLExceptione){
e.printStackTrace();
}
connection=null;
}
} 
}

Connectionconnection=null;
Statementstatement=null;
ResultSetresultSet=null;
try{
//调用工具类中的静态方法来获取连接
connection=JdbcUtil.getConnection();
statement=connection.createStatement();
resultSet=statement.executeQuery("select*fromusers");
while(resultSet.next()){
intid=resultSet.getInt("id");
Stringname=resultSet.getString("name");
Stringpsd=resultSet.getString("password");
Stringemail=resultSet.getString("email");
Stringbirthday=resultSet.getString("birthday");
System.out.println(id+""+name+""+psd+""+email
+""+birthday); 
}
}catch(Exceptione){
e.printStackTrace();
}finally{
//调用工具类中的静态方法来关闭连接，释放资源
JdbcUtil.releaseConn(connection,statement,resultSet);
}