jdbc连接数据库

java.sql.DriverManager用来装载驱动程序，获取数据库连接。
java.sql.Connection完成对某一指定数据库的联接
java.sql.Statement在一个给定的连接中作为SQL执行声明的容器，他包含了两个重要的子类型。
Java.sql.PreparedSatement 用于执行预编译的sql声明
Java.sql.CallableStatement用于执行数据库中存储过程的调用
java.sql.ResultSet对于给定声明取得结果的途径

示例代码——连接mysql：

package cn.itcast.cd.jsp.domain;

import java.util.Date;

public class Student {
private int id;
private String name;
private String sex;
private int age;
private Date birthday;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "Student [id=" + id +
", name=" + name + ", sex=" + sex
+ ", age=" + age + ", birthday=" + birthday +
"]";
}
}

package cn.itcast.cd.utils;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
* 操作JDBC的工具类
* @author dendy
* @version 1.0
*/
public class DbUtils {
private static String url =
"jdbc:mysql://localhost/jdbc";
private static String user =
"root";
private static String password =
"admin";

private DbUtils(){ //不允许工具类拥有实例对象

}

//只需要一份驱动，所以放到静态代码块中
static {
try {
//利用Class.forName调用com.mysql.jdbc.Driver的静态代码块，得到一个Driver对象的实例，而不需要手动创建.
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}

/**
* 获得数据库连接
* @return 返回Jave.sql.Connection实例，发生异常返回null.
*/
public static Connection getConnection(){
try {
Connection connection = DriverManager.getConnection(url, user, password);
return connection;
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}

/**
* 关闭Connection、Statement、ResultSet对象.
* @param connection
* @param statement
* @param resultSet
*/
public static
void close(Connection connection, Statement statement, ResultSet resultSet){
close(connection);
close(statement);
close(resultSet);
}

/**
* 关闭Connection、Statement对象.
* @param connection
* @param statement
*/
public static
void close(Connection connection, Statement statement){
close(connection);
close(statement);
}

/**
* 关闭Connection对象
* @param connection
*/
public static
void close(Connection connection){
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

/**
* 关闭Statement对象
* @param statement
*/
public static
void close(Statement statement){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

/**
* 关闭ResultSet对象
* @param resultSet
*/
public static
void close(ResultSet resultSet){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

package cn.itcast.dao.Impl;

import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import cn.itcast.cd.jsp.dao.IStudentDao;
import cn.itcast.cd.jsp.domain.Student;
import cn.itcast.cd.utils.DbUtils;

public class StudentDao
implements IStudentDao {

@Override
public void add(Student stu) {
// 连接数据库
Connection connection = DbUtils.getConnection();

PreparedStatement preparedStatement = null;
String sql = "INSERT INTO student VALUES (null,?,?,?,?)";
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, stu.getName());
preparedStatement.setString(2, stu.getSex());
preparedStatement.setInt(3, stu.getAge());

// 第二参数为java.sql.Date类型，为java.util.Date的子类，需要处理
preparedStatement.setDate(4, new Date(stu.getBirthday().getTime()));

preparedStatement.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 关闭资源
DbUtils.close(connection, preparedStatement);
}
}

@Override
public void delete(int id) {
// 连接数据库
Connection connection = DbUtils.getConnection();

PreparedStatement preparedStatement = null;
String sql = "DELETE FROM student WHERE id = " + id;
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 关闭资源
DbUtils.close(connection, preparedStatement);
}
}

@Override
public void update(int id, Student stu) {
// 连接数据库
Connection connection = DbUtils.getConnection();

PreparedStatement preparedStatement = null;
String sql = "UPDATE student SET name=?,sex=?,age=?,birthday=? WHERE ID="
+ id;
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, stu.getName());
preparedStatement.setString(2, stu.getSex());
preparedStatement.setInt(3, stu.getAge());
preparedStatement.setDate(4, new Date(stu.getBirthday().getTime()));

preparedStatement.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 关闭资源
DbUtils.close(connection, preparedStatement);
}
}

@Override
public Student get(int id) {
// 连接数据库
Connection connection = DbUtils.getConnection();
ResultSet resultSet = null;
PreparedStatement preparedStatement = null;
String sql = "SELECT * FROM student WHERE ID=" + id;
try {
preparedStatement = connection.prepareStatement(sql);

resultSet = preparedStatement.executeQuery();
if (resultSet.next()) {
Student stu = new Student();
stu.setName(resultSet.getString("name"));
stu.setSex(resultSet.getString("sex"));
stu.setAge(resultSet.getInt("age"));
stu.setBirthday(resultSet.getDate("birthday"));
stu.setId(resultSet.getInt("id"));

return stu;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 关闭资源
DbUtils.close(connection, preparedStatement, resultSet);
}
return null;
}

@Override
public List<Student> getAll() {
List<Student> stuList = new ArrayList<Student>();
// 连接数据库
Connection connection = DbUtils.getConnection();
ResultSet resultSet = null;

PreparedStatement preparedStatement = null;
String sql = "SELECT * FROM student";
try {
preparedStatement = connection.prepareStatement(sql);

resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
Student stu = new Student();
stu.setName(resultSet.getString("name"));
stu.setSex(resultSet.getString("sex"));
stu.setAge(resultSet.getInt("age"));
stu.setBirthday(resultSet.getDate("birthday"));
stu.setId(resultSet.getInt("id"));

stuList.add(stu);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 关闭资源
DbUtils.close(connection, preparedStatement, resultSet);
}
return stuList;
}

@Override
public List<Student> get(String name) {
List<Student> stuList = new ArrayList<Student>();
// 连接数据库
Connection connection = DbUtils.getConnection();
ResultSet resultSet = null;

PreparedStatement preparedStatement = null;
String sql = "SELECT * FROM student WHERE name='"+name+"'";
try {
preparedStatement = connection.prepareStatement(sql);

resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
Student stu = new Student();
stu.setName(resultSet.getString("name"));
stu.setSex(resultSet.getString("sex"));
stu.setAge(resultSet.getInt("age"));
stu.setBirthday(resultSet.getDate("birthday"));
stu.setId(resultSet.getInt("id"));

stuList.add(stu);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 关闭资源
DbUtils.close(connection, preparedStatement, resultSet);
}
return stuList;
}

}