java jdbc 连接mysql 数据库
JDBC连接MySQL
加载及注册JDBC驱动程序
Class.forName("com.mysql.jdbc.Driver");
Class.forName("com.mysql.jdbc.Driver").newInstance();
JDBC URL 定义驱动程序与数据源之间的连接
标准语法：
<protocol（主要通讯协议）>:<subprotocol（次要通讯协议，即驱动程序名称）>:<data source identifier（数据源）>
MySQL的JDBC URL格式：
jdbc:mysql//[hostname][:port]/[dbname][?param1=value1][¶m2=value2]….
示例：
常见参数：
user 用户名 password 密码 autoReconnect 联机失败，是否重新联机（true/false） maxReconnect 尝试重新联机次数 initialTimeout 尝试重新联机间隔 maxRows 传回最大行数 useUnicode 是否使用Unicode字体编码（true/false） characterEncoding 何种编码（GB2312/UTF-8/…） relaxAutocommit 是否自动提交（true/false） capitalizeTypeNames 数据定义的名称以大写表示
package mysqlmanage; import datastructures.QueueArray; import java.sql.SQLException; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Map; import tools.Time; /** * 执行数据库操作之前的业务逻辑 主要执行jdbcUtils类中的命令 * * @author timeless <[email protected]> * 2015年2.26 */ public class ExecCmd { /** * 获取 mysql 连接 * * @return JdbcUtils对象 */ public static JdbcUtils getJdbcUtil() { //数据库用户名 String USERNAME = "root"; //数据库密码 String PASSWORD = "xxxxxx"; //驱动信息 String URL = "jdbc:mysql://localhost:3306/mxManage"; JdbcUtils jdbcUtils = new JdbcUtils(USERNAME, PASSWORD, URL); jdbcUtils.getConnection(); return jdbcUtils; } /** * 执行更新操作 前提是 sql 语句中的数值不为空 * * @param sql 要执行的 insert 或者 update 语句 */ public static void updateInsertData(String sql, JdbcUtils jdbcUtils) { try { System.out.println(sql); jdbcUtils.updateByPreparedStatement(sql, null); } catch (Exception ex) { System.out.println("sql 语句问题：语句为" + sql + "异常为：" + ex.toString()); } finally { jdbcUtils.releaseConn(); } } /** * 执行更新操作 前提是 sql 语句中的数值不为空 * * @param sql 要执行的 insert 或者 update 语句 * @param table 批量出入的表 * @param field 数据表格中的字段 格式为：示例 (`id`, `name`) 每一个字段都需要写上 */ public static String formInsertSql(ArrayList<String> list, String table, String field) { if (list.size() == 0) { return null; } String sql = "INSERT INTO `" + table + "`" + field + " VALUES ";//(null,'dsadsad'),(null,'dss') try { for (String perdomain : list) { sql = sql + "(null,'" + perdomain + "'),"; } //把最后一个字符串","去掉 int end = sql.length(); sql = sql.substring(0, end - 1); } catch (Exception ex) { System.out.println("形成sql语句问题" + ex.toString()); } return sql; } }
package mysqlmanage; import java.lang.reflect.Field; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class JdbcUtils { //数据库用户名 private String USERNAME = ""; //数据库密码 private String PASSWORD = ""; //驱动信息 private String DRIVER = "com.mysql.jdbc.Driver"; //数据库地址 private String URL = ""; private Connection connection; private PreparedStatement pstmt; private ResultSet resultSet; public JdbcUtils(String username, String password, String url) { // TODO Auto-generated constructor stub this.USERNAME = username; this.PASSWORD = password; this.URL = url; try { Class.forName(DRIVER); } catch (Exception ex) { System.out.println("数据库连接失败！" + ex.toString()); } } /** * 获得数据库的连接 * * @return */ public Connection getConnection() { try { connection = DriverManager.getConnection(URL, USERNAME, PASSWORD); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return connection; } /** * 增加、删除、改 * * @param sql * @param params * @return * @throws SQLException */ public boolean updateByPreparedStatement(String sql, List<Object> params) throws SQLException { boolean flag = false; int result = -1; pstmt = connection.prepareStatement(sql); int index = 1; if (params != null && !params.isEmpty()) { for (int i = 0; i < params.size(); i++) { pstmt.setObject(index++, params.get(i)); } } result = pstmt.executeUpdate(); flag = result > 0 ? true : false; return flag; } /** * 查询单条记录 * * @param sql * @param params * @return * @throws SQLException */ public Map<String, Object> findSimpleResult(String sql, List<Object> params) throws SQLException { Map<String, Object> map = new HashMap<String, Object>(); int index = 1; pstmt = connection.prepareStatement(sql); if (params != null && !params.isEmpty()) { for (int i = 0; i < params.size(); i++) { pstmt.setObject(index++, params.get(i)); } } resultSet = pstmt.executeQuery();//返回查询结果 ResultSetMetaData metaData = resultSet.getMetaData(); int col_len = metaData.getColumnCount(); while (resultSet.next()) { for (int i = 0; i < col_len; i++) { String cols_name = metaData.getColumnLabel(i + 1); Object cols_value = resultSet.getObject(cols_name); if (cols_value == null) { cols_value = ""; } map.put(cols_name, cols_value); } } return map; } /** * 查询单条记录 * * @param sql * @param params * @return 是不是含有某条记录 * @throws SQLException */ public boolean verifyDataIsInDatabase(String sql, List<Object> params) throws SQLException { boolean status = false; int index = 1; pstmt = connection.prepareStatement(sql); if (params != null && !params.isEmpty()) { for (int i = 0; i < params.size(); i++) { pstmt.setObject(index++, params.get(i)); } } resultSet = pstmt.executeQuery();//返回查询结果 if (resultSet.next()) { status = true; } return status; } /** * 查询多条记录 * * @param sql * @param params * @return * @throws SQLException */ public List<Map<String, Object>> findModeResult(String sql, List<Object> params) throws SQLException { List<Map<String, Object>> list = new ArrayList<Map<String, Object>>(); int index = 1; pstmt = connection.prepareStatement(sql); if (params != null && !params.isEmpty()) { for (int i = 0; i < params.size(); i++) { pstmt.setObject(index++, params.get(i)); } } resultSet = pstmt.executeQuery(); ResultSetMetaData metaData = resultSet.getMetaData(); int cols_len = metaData.getColumnCount(); while (resultSet.next()) { Map<String, Object> map = new HashMap<String, Object>(); for (int i = 0; i < cols_len; i++) { String cols_name = metaData.getColumnLabel(i + 1); Object cols_value = resultSet.getObject(cols_name); if (cols_value == null) { cols_value = ""; } map.put(cols_name, cols_value); } list.add(map); } return list; } /** * 通过反射机制查询单条记录 * * @param sql * @param params * @param cls * @return * @throws Exception */ public <T> T findSimpleRefResult(String sql, List<Object> params, Class<T> cls) throws Exception { T resultObject = null; int index = 1; pstmt = connection.prepareStatement(sql); if (params != null && !params.isEmpty()) { for (int i = 0; i < params.size(); i++) { pstmt.setObject(index++, params.get(i)); } } resultSet = pstmt.executeQuery(); ResultSetMetaData metaData = resultSet.getMetaData(); int cols_len = metaData.getColumnCount(); while (resultSet.next()) { // 通过反射机制创建一个实例 // cls.class; resultObject = cls.newInstance(); for (int i = 0; i < cols_len; i++) { String cols_name = metaData.getColumnName(i + 1); Object cols_value = resultSet.getObject(cols_name); if (cols_value == null) { cols_value = ""; } Field field = cls.getDeclaredField(cols_name); field.setAccessible(true); //打开javabean的访问权限 field.set(resultObject, cols_value); } } return resultObject; } /** * 通过反射机制查询多条记录 * * @param sql * @param params * @param cls * @return * @throws Exception */ public <T> List<T> findMoreRefResult(String sql, List<Object> params, Class<T> cls) throws Exception { List<T> list = new ArrayList<T>(); int index = 1; pstmt = connection.prepareStatement(sql); if (params != null && !params.isEmpty()) { for (int i = 0; i < params.size(); i++) { pstmt.setObject(index++, params.get(i)); } } resultSet = pstmt.executeQuery(); ResultSetMetaData metaData = resultSet.getMetaData(); int cols_len = metaData.getColumnCount(); while (resultSet.next()) { //通过反射机制创建一个实例 T resultObject = cls.newInstance(); for (int i = 0; i < cols_len; i++) { String cols_name = metaData.getColumnName(i + 1); Object cols_value = resultSet.getObject(cols_name); if (cols_value == null) { cols_value = ""; } Field field = cls.getDeclaredField(cols_name); field.setAccessible(true); //打开javabean的访问权限 field.set(resultObject, cols_value); } list.add(resultObject); } return list; } /** * 释放数据库连接 */ public void releaseConn() { if (resultSet != null) { try { resultSet.close(); } catch (SQLException e) { e.printStackTrace(); } } } }