SUN公司为了简化、统一对数据库的操作，定义了一套Java操作数据库的规范，称之为JDBC。 JDBC全称为：Java Data Base Connectivity（java数据库连接），它主要由接口组成。 组成JDBC的２个包：java.sql javax.sql
开发JDBC应用需要以上2个包的支持外，还需要导入相应JDBC的数据库实现(即数据库驱动)。
需求：编程从user表中读取数据，并打印在命令行窗口中。
(1) 搭建实验环境 ：
a、在mysql中创建一个数据库，并创建user表，同时插入数据到表中。
b、新建一个Java工程，并导入数据库驱动。
(2) 编写程序，在程序中加载数据库驱动
a、方式一：DriverManager. registerDriver(Driver driver)
b、方式二：Class.forName(“com.mysql.jdbc.Driver”);Connection conn = DriverManager.getConnection(url,user,pass);
Statement st = conn.createStatement();
ResultSet rs = st.excuteQuery(sql);dome：
import java.sql.*;
import com.sun.org.apache.regexp.internal.recompile;
public class dome {
/**
* @param args
*/
public static void main(String[] args) throws SQLException,ClassNotFoundException{
// TODO Auto-generated method stub
String url = "jdbc:mysql://localhost:3306/skyfin";
String username = "root";
String password = "skyfin";
//1.加载驱动
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
Class.forName("com.mysql.jdbc.Driver"); //2获取连接
Connection connection = DriverManager.getConnection(url,username,password);
//3.获取向数据库发sql语句的statament对象
Statement stat = connection.createStatement();
//4.向数据库发送sql，获取数据库返回的结果集
ResultSet rsResultSet = stat.executeQuery("select * from user");
//5.从结果集中获取数据while (rsResultSet.next()) {System.out.println("id = "+ rsResultSet.getObject("id"));System.out.println("name = "+ rsResultSet.getObject("name"));
System.out.println("password = "+ rsResultSet.getObject("password"));}
//6.释放资源（释放链接）rsResultSet.close();stat.close();connection.close();}}Jdbc程序中的DriverManager用于加载驱动，并创建与数据库的链接，这个API的常用方法：
DriverManager.registerDriver(new Driver());
DriverManager.getConnection(url, user, password);Class.forName(“com.mysql.jdbc.Driver”);
URL用于标识数据库的位置，程序员通过URL地址告诉JDBC程序连接哪个数据库，
MySql 数据库的URL写法为： jdbc:mysql:［］//localhost:3306/test ?参数名：参数值
常用数据库URL地址的写法：
Oracle:jdbc:oracle:thin:@localhost:1521:skyfin
SqlServer:jdbc:microsoft:sqlserver://localhost:1433; DatabaseName=skyfin
MySql:jdbc:mysql://localhost:3306/skyfin
Mysql的url地址的简写形式： jdbc:mysql://skyfin
常用属性：useUnicode=true&characterEncoding=UTF-8
jdbc:mysql://localhost:3306/test?user=root&password=&useUnicode=true&characterEncoding=gbk&autoReconnect=true&failOverReadOnly
public static void main(String[] args) throws SQLException,ClassNotFoundException{
// TODO Auto-generated method stub
String url = "jdbc:mysql://localhost:3306/skyfin";
String username = "root";
String password = "skyfin";
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection(url,username,password);
Statement stat = connection.createStatement();
/*
* 执行查找操作
*/
ResultSet rsResultSet = stat.executeQuery("select * from user");
while (rsResultSet.next()) {
System.out.println("id = "+ rsResultSet.getObject("id"));
System.out.println("name = "+ rsResultSet.getObject("name"));
System.out.println("password = "+ rsResultSet.getObject("password"));
}
/*
* 执行插入操作
*/
String sql = "insert into user(id,name,password) value(6,"+"'staff'"+","+"'staff'"+")";
System.out.println(sql);
int statentnum = stat.executeUpdate(sql);
if (statentnum>0) {
System.out.println("insert ok");
}
/*
* 执行更新操作
*/
sql = "update user set name = 'skstaff' where name = 'staff'";
System.out.println(sql);
statentnum = stat.executeUpdate(sql);
if (statentnum>0) {
System.out.println("update ok");
}
/*
* 执行删除操作
*/
sql = "delete from user where name = 'skstaff'";
System.out.println(sql);
statentnum = stat.executeUpdate(sql);
if (statentnum>0) {
System.out.println("delete ok");
}
/*
* 资源的释放
*/
rsResultSet.close();
stat.close();
connection.close();
}
public static void main(String[] args) throws SQLException,ClassNotFoundException{
// TODO Auto-generated method stub
String url = "jdbc:mysql://localhost:3306/skyfin";
String username = "root";
String password = "skyfin";
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection(url,username,password);
String sql = "insert into user1(id,name) value(?,?)";
PreparedStatement preparedStatement = connection.prepareStatement(sql);
for(int i = 0;i<10000;i++){
preparedStatement.setInt(1, i);
preparedStatement.setString(2, "skyfin"+i);
preparedStatement.executeUpdate();
}
}
public static void main(String[] args) throws SQLException,ClassNotFoundException{
// TODO Auto-generated method stub
String url = "jdbc:mysql://localhost:3306/skyfin";
String username = "root";
String password = "skyfin";
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection(url,username,password);
String sql = "insert into user1(id,name) value(?,?)";
PreparedStatement preparedStatement = connection.prepareStatement(sql);
for(int i = 0;i<10000;i++){
preparedStatement.setInt(1, i);
preparedStatement.setString(2, "skyfin"+i);
//preparedStatement.executeUpdate();
/*
* 使用executeBatch()
*/
preparedStatement.addBatch();
}
//执行批处理
preparedStatement.executeBatch();
}注意：1. 如果使用了 addBatch() -> executeBatch() 还是很慢，那就得使用到这个参数了rewriteBatchedStatements=true (启动批处理操作)
public static void main(String[] args) throws SQLException,ClassNotFoundException{
// TODO Auto-generated method stub
String url = "jdbc:mysql://localhost:3306/skyfin";
String username = "root";
String password = "skyfin";
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection(url,username,password);
//关闭自动提交
connection.setAutoCommit(false);
String sql = "update user1 set name = ?where id = ?";
PreparedStatement preparedStatement = connection.prepareStatement(sql);
for(int i = 0;i<10000;i++){
preparedStatement.setString(1, "loco"+i);
preparedStatement.setInt(2, i);
//preparedStatement.executeUpdate();
/*
* 使用executeBatch()
*/
preparedStatement.addBatch();
}
//执行批处理
preparedStatement.executeBatch();
preparedStatement.close();
//执行完后手动提交事务
connection.commit();
//打开自动提交
connection.setAutoCommit(true);
connection.close();
}
public static void main(String[] args) throws SQLException,ClassNotFoundException{
// TODO Auto-generated method stub
String url = "jdbc:mysql://localhost:3306/skyfin";
String username = "root";
String password = "skyfin";
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection(url,username,password);
//关闭自动提交
connection.setAutoCommit(false);
String sql = "update user1 set name = ?where id = ?";
PreparedStatement preparedStatement = connection.prepareStatement(sql);
for(int i = 0;i<10000;i++){
preparedStatement.setString(1, "skyfin"+i);
preparedStatement.setInt(2, i);
//preparedStatement.executeUpdate();
/*
* 使用executeBatch()
*/
if (i>0&&i%500 == 0) {
preparedStatement.executeBatch();
//如果不想出错后，完全没保留数据，则可以没执行一次提交一次，但得保证数据不会重复
connection.commit();
}
preparedStatement.addBatch();
}
//执行批处理
preparedStatement.executeBatch();
preparedStatement.close();
//执行完后手动提交事务
connection.commit();
//打开自动提交
connection.setAutoCommit(true);
connection.close();
}
public List<customer> getAll(){
Connection conn = null;
PreparedStatement st = null;
ResultSet rs = null;
try{
conn = JdbcUtils.getConnection();
String sql = "select * from customer";
st = conn.prepareStatement(sql);
rs = st.executeQuery();
List list = new ArrayList();
while(rs.next()){
Customer c = new Customer();
c.setBirthday(rs.getDate("birthday"));
c.setCellphone(rs.getString("cellphone"));
c.setDescription(rs.getString("description"));
c.setEmail(rs.getString("email"));
c.setGender(rs.getString("gender"));
c.setId(rs.getString("id"));
c.setName(rs.getString("name"));
c.setPreference(rs.getString("preference"));
c.setType(rs.getString("type"));
list.add(c);
}
return list;
}catch (Exception e) {
throw new DaoException(e);
}finally{
JdbcUtils.release(conn, st, rs);
}
}
</customer>
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