利用JDBC连接MySQL并使用MySQL

driver为JDBC的驱动。

url为数据库的地址。

usrname和password分别为数据库的用户名和密码。

Connection类用来连接MySQL。

PreparedStatement类用来预编译sql语句，并可以执行。有的地方也用Statement。因为PreparedStatement继承了Statement，并且在执行多次查询更新的时候比Statement更快。PreparedStatement的第一次执行消耗是很高的，它的性能体现在重复执行。比如当我使用PreparedStatement来进行查询的时候，JDBC会发送一个网络请求来编译这个查询语句，在执行时会产生另外一个网络请求来执行。但是当我执行多次相同的查询的时候，使用PreparedStatement只会产生一个网络请求来执行语句。但如果使用Statement还会产生一个网络请求来编译语句。

ResultSet用来存储结果，一般用到select语句时用。

import java.sql.*;

class MySQL {
	private static final String driver = "com.mysql.jdbc.Driver";
	private static final String url = "jdbc:mysql://localhost:3306/school";
	private static final String usrname = "root";
	private static final String password = "";
	private Connection con = null;
	private PreparedStatement ps = null;
	private ResultSet rs = null;

	//创建student表
	public MySQL() {
		//如果不存在Student表则创建
		String sql = "create table if not exists Student(name char(10), "
				+ "sno char(10) primary key, age smallint, sex char(6), "
				+ "sdept char(4))";
		//加载驱动
		try {
			Class.forName(driver);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}

		try {
			con = DriverManager.getConnection(url, usrname, password);//连接数据库
			ps = con.prepareStatement(sql);//预编译sql语句
			ps.executeUpdate();//执行sql语句更新

			//必须按顺序关闭并且必须关闭
			try {
				if (ps != null)
					ps.close();
				if (con != null)
					con.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}

		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	//插入多条信息
	public void addInfo(String[] name, String[] sno, int[] age, String[] sex,
			String[] sdept) {
		String sql = "insert into student(name, sno, age, sex, sdept) "
				+ "values(?, ?, ?, ?, ?);";
		try {
			Class.forName(driver);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}

		try {
			con = DriverManager.getConnection(url, usrname, password);
			ps = con.prepareStatement(sql);//只需要预编译一次
			for (int i = 0; i < name.length; i++) {
				ps.setString(1, name[i]);
				ps.setString(2, sno[i]);
				ps.setInt(3, age[i]);
				ps.setString(4, sex[i]);
				ps.setString(5, sdept[i]);
				ps.executeUpdate();
			}

			try {
				if (ps != null)
					ps.close();
				if (con != null)
					con.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	//删除多条信息
	public void deleteInfo(String[] name) {
		String sql = "delete from student where name = ? ;";
		try {
			Class.forName(driver);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}

		try {
			con = DriverManager.getConnection(url, usrname, password);
			ps = con.prepareStatement(sql);
			for (int i = 0; i < name.length; i++) {
				ps.setString(1, name[i]);
				ps.executeUpdate();
			}

			try {
				if (ps != null)
					ps.close();
				if (con != null)
					con.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}

		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	//查询多条信息
	public void searchInfo(String[] name) {
		String sql = "select * from student where name like ? ;";
		try {
			Class.forName(driver);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}

		try {
			con = DriverManager.getConnection(url, usrname, password);
			ps = con.prepareStatement(sql);
			for (int i = 0; i < name.length; i++) {
				ps.setString(1, name[i]);
				rs = ps.executeQuery();//返回的查询结果存在结果集里面

				if (rs.next()) {
					do {
						System.out.println("Name: " + rs.getString(1) + ", Sno: "
								+ rs.getString(2) + ", age:" + rs.getString(3)
								+ ", sex: " + rs.getString(4) + ", sdept: "
								+ rs.getString(5));
					} while (rs.next());
				}
				else {
					System.out.println("There is no one named " + name[i] + ".");
				}
			}

			try {
				if (rs != null)
					rs.close();
				if (ps != null)
					ps.close();
				if (con != null)
					con.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

public class TestJDBC {
	static String[] name = {"Mike", "Tom", "Jack", "Amy", "Allen"};
	static String[] sno = {"2013210001", "2013210002", "2013210003", "2013210004", "2013210005", };
	static int[] age = {21, 22, 25, 20, 24};
	static String[] sex = {"female", "female", "female", "male", "male"};
	static String[] sdept = {"CS", "EE", "SE", "CS", "SE"};

	public static void main(String[] args) {
		//创建Student表
		System.out.println("Creating table student!");
		MySQL sq = new MySQL();

		//添加学生信息
		System.out.println("\nTesting add data!");
		sq.addInfo(name, sno, age, sex, sdept);

		//删除Tom和Allen的信息
		System.out.println("\nTesting delete data!");
		String[] del = {"Tom", "Allen"};
		sq.deleteInfo(del);

		//查询Tom，Amy和Mike的信息。
		System.out.println("\nTesting search data!");
		String[] sear = {"Tom", "Amy", "Mike"};
		sq.searchInfo(sear);

		System.out.println("\nSuccess!");
	}
}

上述代码运行结果如下

Creating table student!

Testing add data!

Testing delete data!

Testing search data!
There is no one named Tom.//因为上一部已经将Tom删除
Name: Amy, Sno: 2013210004, age:20, sex: male, sdept: CS
Name: Mike, Sno: 2013210001, age:21, sex: female, sdept: CS

Success!