JDBC--01

jdbc(mysql)配置文件
文件名：database.properties
以下为配置文件里所写的信息：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/6521?useUnicode=true&characterEncoding=utf8
user=root
password=root

?useUnicode=true&characterEncoding=utf8此为设置编码。注意mysql设置为utf-8时写的是utf8。
注意，配置文件中不要有空格！

JDBC加载工具类方式一：
package com.it.JDBC;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ResourceBundle;

public class JDBCUtils_V1 {
    private static String driver = null;
    private static String url = null;
    private static String user = null;
    private static String password = null;

    /**
     * @author Payphone
     * @time 2017-10-01 加载配置信息
     * */
    static {
        ResourceBundle bundle = ResourceBundle.getBundle("database");
        driver = bundle.getString("driver");
        url = bundle.getString("url");
        user = bundle.getString("user");
        password = bundle.getString("password");
    }

    /**
     * @time 2017-10-01
     * @author Payphone连接数据库
     * */
    public static Connection getConnection() {
        Connection conn = null;
        try {
            // 1 加载驱动
            Class.forName(driver);
            // 2获得连接
            conn = DriverManager.getConnection(url, user, password);
            if (conn != null) {
                System.out.println("连接成功");
            } else {
                System.out.println("失败了");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }

    /**
     * @author Payphone释放资源
     * @time 2017-10-01
     * */
    public static void Release(Connection conn, PreparedStatement psmt,
            ResultSet rs) {
        try {
            if (rs != null) {
                conn.close();
            }
            if (psmt != null) {
                psmt.close();
            }
            if (conn != null) {
                conn.close();
            }
            System.out.println("释放资源成功");
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }
}

JDBC加载工具类方式二：
package com.it.JDBC;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
import org.junit.Test;

public class JDBCUtils_V2 {
    private static String driver = null;
    private static String url = null;
    private static String user = null;
    private static String password = null;

    /**
     * @author Payphone
     * @time 2017-10-01 加载配置信息
     * */
    static {
        try {
            // 1.通过当前类获取类加载器
            ClassLoader classLoader = JDBCUtils_V2.class.getClassLoader();
            // 2.通过类加载器的方法获得一个输入流
            InputStream is = classLoader
                    .getResourceAsStream("database.properties");
            // 3.创建一个properties对象
            Properties props = new Properties();
            // 4.加载输入流
            props.load(is);
            // 5.获取相关参数的值
            driver = props.getProperty("driver");
            url = props.getProperty("url");
            user = props.getProperty("user");
            password = props.getProperty("password");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        

    }

    /**
     * @time 2017-10-01
     * @author Payphone连接数据库
     * */
    @Test
    public static Connection getConnection() {
        Connection conn = null;
        try {
            // 1 加载驱动
            Class.forName(driver);
            // 2获得连接
            conn = DriverManager.getConnection(url, user, password);
            if (conn != null) {
                System.out.println("连接成功");
            } else {
                System.out.println("失败了");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }

    /**
     * @author Payphone释放资源
     * @time 2017-10-01
     * */
    public static void Release(Connection conn, PreparedStatement psmt,
            ResultSet rs) {
        try {
            if (rs != null) {
                conn.close();
            }
            if (psmt != null) {
                psmt.close();
            }
            if (conn != null) {
                conn.close();
            }
            System.out.println("释放资源成功");
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }
}

JDCB测试类(测试用的junit)：
package com.it.JDBC;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.junit.Test;

/**
 * @author Payphone
 * @version 1.0
 * @描述 数据库操作工具类，主要进行增删改查
 */
public class JDBCUtilsTest {
    Connection conn = null;
    PreparedStatement psmt = null;
    ResultSet rs = null;
    String sql = null;

    /**
     * @author Payphone
     * @version 1.0
     * @描述 根据id查找用户信息
     */
    @Test
    public void findById() {
        try {
            // 1 获取连接
            conn = JDBCUtils_V2.getConnection();
            sql = "select * from t_user where id=?";
            psmt = conn.prepareStatement(sql);
            psmt.setInt(1, 2015008);
            rs = psmt.executeQuery();
            while (rs.next()) {
                System.out.println(rs.getString("id") + ":"
                        + rs.getString("pwd"));
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            JDBCUtils_V2.Release(conn, psmt, rs);
        }
    }

    /**
     * 插入用户信息
     */
    @Test
    public void insertMessage() {
        try {
            conn = JDBCUtils_V1.getConnection();
            sql = "insert into t_user(id,pwd) values(?,?)";
            PreparedStatement psmt = conn.prepareStatement(sql);
            psmt.setInt(1, 2015002);
            psmt.setString(2, "2015002");
            int rs = psmt.executeUpdate();
            if (rs > 0) {
                System.out.println("插入成功！");
            }
        } catch (SQLException e) {
            System.out.println("插入失败，数据重复了！");
            e.printStackTrace();
        } finally {
            JDBCUtils_V1.Release(conn, psmt, null);
        }
    }

    /**
     * 更新用户的信息
     * */
    @Test
    public void updateMessage() {
        try {
            conn = JDBCUtils_V1.getConnection();
            sql = "update t_user set pwd=? where id=?";
            psmt = conn.prepareStatement(sql);
            psmt.setString(1, "LH");
            psmt.setInt(2, 2015002);
            int r = psmt.executeUpdate();
            if (r > 0) {
                System.out.println("密码修改成功" + ":");
            }
        } catch (SQLException e) {
            System.out.println("密码修改失败！");
            e.printStackTrace();
        } finally {
            JDBCUtils_V1.Release(conn, psmt, null);
        }
    }

    /**
     * 根据用户id删除信息
     * */
    @Test
    public void deleteById() {
        try {
            conn = JDBCUtils_V1.getConnection();
            sql = "delete from t_user where id=?";
            psmt = conn.prepareStatement(sql);
            psmt.setInt(1, 2015002);
            int r = psmt.executeUpdate();
            if(r>0){
                System.out.println("删除成功");
            }
        } catch (SQLException e) {
            System.out.println("删除失败");
            e.printStackTrace();
        } finally {
            JDBCUtils_V1.Release(conn, psmt, null);
        }
    }
}

第二篇JDBC的将推送JDBC连接池的。