javaweb
一.学习的内容
1.什么是JDBC
是java数据库连接，它是一套用于执行SQL语句的JavaAPI。
2，JDBC常用的API
（1）Driver接口；（2）DriverManger接口；（3）Connection接口；（4）Statement接口；（5）PreparedStatement接口；（6）ResultSet接口
3.编写代码如下：
（1）
package cn.itcast;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class example1 {
public static void main(String[] args) throws SQLException{
Statement stmt = null;
ResultSet rs = null;
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/jdbc?serverTimezone=UTC";
String username = "root";
String password = "123456";
conn = DriverManager.getConnection(url, username, password);
stmt = conn.createStatement();
String sql = "select * from users";
rs = stmt.executeQuery(sql);
System.out.println("id | name | password | email | birthday");
while (rs.next()) {
int id = rs.getInt("id");
String name = rs.getString("name");
String psw = rs.getString("password");
String email = rs.getString("email");
Date birthday = rs.getDate("birthday");
System.out.println(id+"|"+name+"|"+psw+"|"+email+"|"+birthday);
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}finally {
if (rs!=null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
rs = null;
}
if (stmt!=null) {
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
stmt = null;
}
if (conn!=null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
conn = null;
}
}
}
}
（2）
package cn.itcast;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class example2 {
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/jdbc?serverTimezone=UTC";
String username = "root";
String password = "123456";
conn = DriverManager.getConnection(url, username, password);
String sql = "select * from users";
stmt =conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
ResultSet rs = stmt.executeQuery(sql);
System.out.print("第2条数据的name值为：");
rs.absolute(2);
System.out.println(rs.getString("name"));
System.out.print("第1条数据的name值为：");
rs.beforeFirst();
rs.next();
System.out.println(rs.getString("name"));
System.out.print("第4条数据的name值为：");
rs.afterLast();
rs.previous();
System.out.println(rs.getString("name"));
} catch (Exception e) {
e.printStackTrace();
}finally {
if (stmt!=null) {
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
stmt = null;
}
if (conn!=null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
conn = null;
}
}
}
}
（3）
package cn.itcast;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class example3 {
public static void main(String[] args) throws SQLException{
Connection conn = null;
PreparedStatement preStmt = null;
try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/jdbc?serverTimezone=UTC";
String username = "root";
String password = "123456";
conn = DriverManager.getConnection(url, username, password);
String sql = "INsERT INTO users(name,password,email,birthday)"
+"VALUES(?,?,?,?)";
preStmt = conn.prepareStatement(sql);
preStmt.setString(1, "zl");
preStmt.setString(2, "123456");
preStmt.setString(3, "[email protected]");
preStmt.setString(4, "1789-12-23");
preStmt.executeUpdate();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}finally {
if (preStmt!=null) {
try {
preStmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
preStmt = null;
}
if (conn!=null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
conn = null;
}
}
}
}
（4）
package cn.itcast.dao;
import java.sql.Date;
public class User {
public void setId(int int1) {
// TODO Auto-generated method stub
}
public void setUsername(String string) {
// TODO Auto-generated method stub
}
public void setPassword(String string) {
// TODO Auto-generated method stub
}
public void setEmail(String string) {
// TODO Auto-generated method stub
}
public void setBirthday(Date date) {
// TODO Auto-generated method stub
}
}
（5）
package cn.itcast.utils;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class JDBCUtils {
public static Connection getConnection() throws SQLException,ClassNotFoundException{
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/jdbc?serverTimezone=UTC";
String username = "root";
String password = "123456";
Connection conn = DriverManager.getConnection(url, username, password);
return conn;
}
public static void release(Statement stmt,Connection conn) {
if (stmt!=null) {
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
stmt=null;
}
if (conn!=null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
conn=null;
}
}
public static void release(ResultSet rs,Statement stmt,Connection conn) {
if (rs!=null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
rs=null;
}
release(stmt, conn);
}
public static Connection getCon() {
// TODO Auto-generated method stub
return null;
}
public static void realse(Object object, Statement stmt, Connection conn) {
// TODO Auto-generated method stub
}
}
（6）
package cn.itcast.dao;
import java.sql.Connection;
import java.sql.Statement;
import javax.management.RuntimeErrorException;
import cn.itcast.domain.User;
import cn.itcast.utils.JDBCUtils;
public class usesdao {
private boolean ture;
public boolean insert(User user) {
Connection conn = null;
Statement stmt = null;
try {
conn=JDBCUtils.getCon();
stmt=conn.createStatement();
java.util.Date brithday=user.getBirthday();
String sqlBirthDay=String.format("%tF", "birthday");
String sql="insert into user(id,name,password,email,birthday)"+"values("
+user.getId()+"','"
+user.getUsername()+"','"
+user.getPassword()+"','"
+user.getEmail()+"','"
+sqlBirthDay+"','"
+")";
System.out.println(sql);
int row =stmt.executeUpdate(sql);
if(row>0) {
return ture;
}
}catch(Exception e) {
throw new RuntimeException(e);
}finally {
JDBCUtils.realse(null,stmt,conn);
}
return false;
}
}
（7）
package cn.itcast.jdbc.excample;
import java.util.Date;
import cn.itcast.dao.UsersDao;
import cn.itcast.domain.User;
public class JdbcInsertTest {
public static void main(String[] args) {
UsersDao dao = new UsersDao();
User user = new User();
user.setId(5);
user.setUsername("h1");
user.setPassword("123");
user.setEmail("[email protected]");
user.setBirthDay(new Date());
boolean flag= dao.insert(user);
}
}
（8）
package cn.itcast.jdbc.excample;
import cn.itcast.dao.UsersDao;
import cn.itcast.domain.User;
public class FindUserByldTest {
public static void main(String[] args) {
UsersDao usersDao = new UsersDao();
User user = usersDao.find(1);
System.out.println("id为1的User对象的name值为："+user.getUsername());
}
}
效果图如下
