MySQL与JDBC连接

必须的准备工作
一、MySQL的安装。可以参考博文：http://blog.csdn.net/jueblog/article/details/9499245
二、下载 jdbc 驱动。可以从在官网上下载，或者点击 http://download.csdn.net/detail/oyuntaolianwu/5822697 下载
三、在 Eclipse 的 Java 工程中新建一个 lib 文件夹，将所准备的 JAR 包复制进去。
四、右键该 JAR 包：Build Path --> Add to Build Path

连接的理论知识
需要用到 Java.sql.*; 中的几个相关类：
Connection类
负责建立与指定URL(包含数据库IP地址、库名、用户名和密码的信息)的连接；
Connection conn = DriverManager.getConnection(url,user,password);

DriverManager.getConnection(url);
利用驱动管理器类获取指定URL连接
[java] view plaincopy

    String url = "jdbc:mysql://localhost:3306/test";    //连接URL为   jdbc:mysql//服务器地址/数据库名   

Statement类
stmt = conn.createStatment();
语句对象，用来向数据库发送一条SQL语句
rs = stmt.executeQuery(sql)  //返回记录集对象，用于查询
int count = stmt.executeUpdate(sql) //执行一条增删改语句，返回int
stmt.execute(sql) //增删改都可以，返回布尔值(执行成功or失败)
ResultSet类
记录集对象，存储executeQuery()方法返回的记录集合。用相关的rs.getString("列名") rs.getInt("列名")等方法获取指定列的值。


连接测试
Java代码如下：
[java] view plaincopy

    package com.sql;  
      
    import java.sql.*;  
      
    public class JDBC0726_Base {  
        Connection connection;  
        Statement statement;  
        ResultSet rSet;  
        //返回一个与特定数据库的连接  
        public Connection getConnection() {  
            try {  
                //连接URL为   jdbc:mysql//服务器地址/数据库名  ，后面的2个参数分别是登陆用户名和密码  
                connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "yongqiang");  
            } catch (SQLException e) {  
                // TODO Auto-generated catch block  
                e.printStackTrace();  
            }  
            return connection;  
        }  
        public static void main(String[] args) {  
            JDBC0726_Base jDao = new JDBC0726_Base();  
            System.out.println(jDao.getConnection());  
        }  
    }  


如果输出相应的对象地址，而不是异常，则证明连接成功。
如输出：com.mysql.jdbc.JDBC4Connection@200bde


用 Java  对SQL进行相关操作
【注】以下操作需要依托于上面的 getConnection() 方法
非查询类SQL语句
[java] view plaincopy

    //非查询类  
    public int Update(String sql) {  
        getConnection();  
        int count =0;  
        try {  
            statement = connection.createStatement();  
            count = statement.executeUpdate(sql);  
        } catch (SQLException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        } finally{  
            try {  
                if (statement != null) {  
                    statement.close();  
                    statement = null;  
                }  
                if (connection != null) {  
                    connection.close();  
                    connection = null;  
                }  
            } catch (SQLException e2) {  
                // TODO: handle exception  
            }  
        }  
        return count;  
    }  


应用：
[java] view plaincopy

    System.out.println(jDao.Update("INSERT INTO t_user(username,password,sex) values('hehe','131','n');"));  

输出值为 1 则证明添加成功。

查询类 SQL 并返回多条记录
[java] view plaincopy

    //执行一条查询类SQL，返回多条记录集  
    public void Qurty(String sql) {  
        getConnection();  
        try {  
            statement = connection.createStatement();  
            rSet = statement.executeQuery(sql);  
            System.out.println("id\t" + "realName\t"+"school\t");  
            while (rSet.next()) {  
                System.out.println(rSet.getRow()+ "----" + rSet.getString("id") + "\t" + rSet.getString("realName") + "\t" + rSet.getString("school") + "\t");  
            }  
        } catch (SQLException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        } finally{  
            try {  
                if (statement != null) {  
                    statement.close();  
                    statement = null;  
                }  
                if (rSet != null) {  
                    rSet.close();  
                    rSet = null;  
                }  
            } catch (SQLException e2) {  
                // TODO: handle exception  
            }  
        }  
    }  

应用举例：
[java] view plaincopy

    jDao.Qurty("SELECT * FROM t_user WHERE sex='女';");  
    System.out.println("-----------------------------");  
    jDao.Qurty("SELECT * FROM t_user;");  
    System.out.println("-----------------------------");  


查询类 SQL 并返回一条记录
[java] view plaincopy

    //执行一条查询类SQL，返回单条记录集  
    public void QurtyByUnique(String sql) {  
        getConnection();  
        try {  
            statement = connection.createStatement();  
            rSet = statement.executeQuery(sql);  
            System.out.println("id\t" + "realName\t"+"school\t");  
            if (rSet.next()) {  
                System.out.println(rSet.getInt("id") + "\t" + rSet.getString("realName") + "\t" + rSet.getString("school") + "\t");  
            }  
        } catch (SQLException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        } finally{  
            try {  
                if (statement != null) {  
                    statement.close();  
                    statement = null;  
                }  
                if (rSet != null) {  
                    rSet.close();  
                    rSet = null;  
                }  
            } catch (SQLException e2) {  
                // TODO: handle exception  
            }  
        }  
    }  

应用举例：
[java] view plaincopy

    jDao.QurtyByUnique("SELECT * FROM t_user WHERE sex='女';");  
    System.out.println("-----------------------------");  
    jDao.QurtyByUnique("SELECT * FROM t_user;");  
    System.out.println("-----------------------------");  


输出表单所有数据
[java] view plaincopy

    public void QurtyTest(String sql) {  
        getConnection();  
        try {  
            statement = connection.createStatement();  
            rSet = statement.executeQuery(sql);  
            while (rSet.next()) {  
                System.out.print(rSet.getRow()+ "----" );  
                for (int i = 1; i < 14; i++) {  
                    System.out.print(rSet.getString(i) +"\t");  
                }  
                System.out.println();  
            }  
        } catch (SQLException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        } finally{  
            try {  
                if (statement != null) {  
                    statement.close();  
                    statement = null;  
                }  
                if (rSet != null) {  
                    rSet.close();  
                    rSet = null;  
                }  
            } catch (SQLException e2) {  
                // TODO: handle exception  
            }  
        }  
    }<span style="font-family:Arial,Helvetica,sans-serif">  </span>