JAVA数据库连接的另一种实现及简单的数据插入及显示

教材是JDK8的，家里也可以正规的测试JDK8，

但公司电脑是JDK6的，所以代码要相应的变动一下下，以适应老的TRY语句。

Message.java

package cc.openhome;

import java.io.Serializable;

public class Message implements Serializable {
private Long id;
private String name;
private String email;
private String msg;

public Message() {}
public Message(String name, String email, String msg) {
this.name = name;
this.email = email;
this.msg = msg;
}

public String getEmail(){
return email;
}
public void setEmail(String email) {
this.email = email;
}

public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}

public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

MessageDAO.java

package cc.openhome;

import java.sql.*;
import java.util.*;

public class MessageDAO {
private String url;
private String user;
private String passwd;

public MessageDAO(String url, String user, String passwd) {
this.url = url;
this.user = user;
this.passwd = passwd;
}

public void add(Message message) {
try {
Connection conn = DriverManager.getConnection(url, user, passwd);
Statement statement = conn.createStatement();
statement.executeUpdate(
"INSERT INTO t_message(name, email, msg) VALUES('"
+ message.getName() + "', '"
+ message.getEmail() + "', '"
+ message.getMsg() + "')");
} catch (SQLException e) {
throw new RuntimeException(e);
}
}

public List<Message> get() {
List<Message> messages = null;
try {
Connection conn = DriverManager.getConnection(url, user, passwd);
Statement statement = conn.createStatement();
ResultSet result = statement.executeQuery(
"SELECT * FROM t_message");
messages = new ArrayList<Message>();
while(result.next()) {
Message message = new Message();
message.setId(result.getLong(1));
message.setName(result.getString(2));
message.setEmail(result.getString(3));
message.setMsg(result.getString(4));
messages.add(message);
}
} catch (SQLException e) {
throw new RuntimeException(e);
}
return messages;
}
}

MessageDAODemo.java

package cc.openhome;

import java.util.Scanner;

public class MessageDAODemo {
public static void main(String args[]) throws Exception {
Scanner scanner = new Scanner(System.in);
MessageDAO dao = new MessageDAO(
"jdbc:mysql://1.2.3.4:3306/demo?" +
"useUnicode=true&characterEncoding=UTF8",
"user", "pwd");
while (true) {
System.out.print("(1) Show Message (2) Add Message: ");
switch(Integer.parseInt(scanner.nextLine())) {
case 1:
for (Message message : dao.get()) {
System.out.printf("%d\t%s\t%s\t%s%n",
message.getId(),
message.getName(),
message.getEmail(),
message.getMsg());
}
break;
case 2:
System.out.print("Name: ");
String name = scanner.nextLine();
System.out.print("Email: ");
String email = scanner.nextLine();
System.out.print("Message: ");
String msg = scanner.nextLine();
dao.add(new Message(name, email, msg));
}
}
}
}

注意编译命令的先后顺序（何时带-d. 何时带-cp . 何时需要引用MYSQL的jdbc驱动和自己的类;）