多线程与服务器：
Server：
public class Server {
boolean started = false;
ServerSocket ss = null;
List<ChatClient> clients = new ArrayList<ChatClient>(); //保存客户端线程类
public static void main(String[] args) {
new Server().start();
}
void start() {
try {
ss = new ServerSocket(8888); //建立服务端对象
started = true;
} catch (BindException e) {
System.out.println("端口使用中");
} catch (IOException e) {
e.printStackTrace();
}
try {
while (started) {
Socket s = ss.accept(); //接收客户端
ChatClient c = new ChatClient(s);
System.out.println("客戶端接收成功");
new Thread(c).start(); //启动线程
clients.add(c); //添加线程类
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
ss.close();
} catch (IOException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
}
}
}
class ChatClient implements Runnable { //建立客户端线程接收，发送数据
private Socket s;
DataInputStream dis = null;
DataOutputStream dos = null;
boolean bConnected = false;
public ChatClient(Socket s) {
this.s = s;
try {
dis = new DataInputStream(s.getInputStream());
dos = new DataOutputStream(s.getOutputStream());
bConnected = true;
} catch (IOException e) {
e.printStackTrace();
}
}
void send(String str) {
try {
dos.writeUTF(str);
} catch (SocketException e) {
System.out.println("對方退出了");
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
try {
while (bConnected) {
String str = dis.readUTF();
// System.out.println(str);
for (int i = 0; i < clients.size(); i++) {
ChatClient c = clients.get(i);
c.send(str);
}
}
} catch (EOFException e) {
System.out.println("客戶端退出了");
} catch (IOException e) {
// e.printStackTrace();
System.out.println("没有客户端");
} finally {
if (dis != null)
if (s != null)
try {
dis.close();
s.close();
dos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
Client（客户端）：
public class Client extends Frame { //繼承Frame类
TextField tf = new TextField(); //输入框对象
TextArea ta = new TextArea(); //显示框对象
Socket s = null;
DataOutputStream dos = null;
DataInputStream dis = null;
boolean bConnected = false;
recvThread r = new recvThread(); //线程类
public static void main(String[] args) {
new Client().creatFrame();
}
public void creatFrame() { //产生图形界面
this.setBounds(300, 300, 300, 300);
ta.setEditable(false);
this.add(tf, BorderLayout.SOUTH);
this.add(ta, BorderLayout.NORTH);
this.addWindowListener(new WindowAdapter() { //响应关闭窗口事件
public void windowClosing(WindowEvent e) {
disconnect();
System.exit(0);
}
});
tf.addActionListener(new tfListener()); //响应输入事件
this.pack();
this.setVisible(true);
connect();
new Thread(r).start();
}
public void connect() {
try {
s = new Socket("127.0.0.1", 8888); //建立客户端对象
dos = new DataOutputStream(s.getOutputStream());
dis = new DataInputStream(s.getInputStream());
bConnected = true;
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public void disconnect() { //窗口关闭时关闭客户端，输入，输出
try {
dos.close();
dis.close();
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
class tfListener implements ActionListener { //输入框实现的接口，响应输入事件
public void actionPerformed(ActionEvent e) {
String str = tf.getText();
//ta.setText(str);
tf.setText("");
try {
dos.writeUTF(str);
dos.flush();
//dos.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
class recvThread implements Runnable { //客户端线程接收数据
public void run() {
try {
while (bConnected) {
String str;
str = dis.readUTF(); //拿到数据
ta.setText(ta.getText() + str + "/n");//显示到显示框中
}
} catch (SocketException e) {
System.out.println("退出了");
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
Java与数据库的增删改查：
Util类：public class JDBCUtil {
private static String url;
private static String username;
private static String passwd;
private static String drivername;
static {
Properties p = new Properties();
try {
p.load(new FileInputStream("db.properties"));
// 读取文件
url = p.getProperty("url");
username = p.getProperty("username");
passwd = p.getProperty("passwd");
drivername = p.getProperty("drivername");
} catch (IOException e) {
// 如果文件读取出错的话，我们给这四个变量一个默认值
e.printStackTrace();// 打印Exception的信息
url = "jdbc:mysql://localhost:3306/student";
username = "root";
passwd = "";
drivername = "com.mysql.jdbc.Driver";
}
// 加载数据库驱动
try {
Class.forName(drivername);
} catch (ClassNotFoundException e) {
e.printStackTrace();
System.exit(0);
}
}
public static Connection getConnection() {
try {
return DriverManager.getConnection(url, username, passwd);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
/**
* 1、Connection 2、Statement 3、ResultSet
*
*/
public static void close(PreparedStatement ps, Connection conn) {
try {
if (ps != null)
ps.close();
if (conn != null)
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void close(ResultSet rs, PreparedStatement ps, Connection conn) {
try {
close(ps, conn);
if (rs != null)
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
SQLTool类：
public class SQLTool {
public void insertStudent(Student stu) {
// 将这些数据写入到数据库中
// 1、链接数据库
Connection conn = JDBCUtil.getConnection();
// 2、创建sql语句
String sql = "insert into student values(?,?,?,?,?,?,?)";
// 3、创建一个PreparedStaement
PreparedStatement ps = null;
try {
ps = conn.prepareStatement(sql);
ps.setString(1, stu.getSno());
ps.setString(2, stu.getSname());
ps.setString(3, stu.getGender());
ps.setString(4, stu.getProfessinal());
ps.setString(5, stu.getClassis());
ps.setString(6, stu.getGrade());
// stu：java.util.Date
// sql:java.sql.Date
ps.setDate(7, new java.sql.Date(stu.getIntime().getTime()));
ps.executeUpdate();
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
} finally {
JDBCUtil.release(null, ps, conn);
}
}
public void deleteStudent(String sno) {
// 将这些数据写入到数据库中
// 1、链接数据库
Connection conn = JDBCUtil.getConnection();
// 2、创建sql语句
String sql = "delete from student where sno=?";
// 3、创建一个PreparedStaement
PreparedStatement ps = null;
try {
ps = conn.prepareStatement(sql);
ps.setString(1, sno);
ps.executeUpdate();
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
} finally {
JDBCUtil.release(null, ps, conn);
}
}
/**
* String sql = "update student set sname=?,gender=?,professional=?,classis=?,grade=?,intime=?" +
" where sno=?";
* @param sno
* @return
*/
public void updateStudent(Student stu) {
// 将这些数据写入到数据库中
// 1、链接数据库
Connection conn = JDBCUtil.getConnection();
// 2、创建sql语句
String sql = "update student set sname=?,gender=?,professional=?,classis=?,grade=?,intime=?" +
" where sno=?";
// 3、创建一个PreparedStaement
PreparedStatement ps = null;
try {
ps = conn.prepareStatement(sql);
ps.setString(7, stu.getSno());
ps.setString(1, stu.getSname());
ps.setString(2, stu.getGender());
ps.setString(3, stu.getProfessinal());
ps.setString(4, stu.getClassis());
ps.setString(5, stu.getGrade());
// stu：java.util.Date
// sql:java.sql.Date
ps.setDate(6, new java.sql.Date(stu.getIntime().getTime()));
ps.executeUpdate();
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
} finally {
JDBCUtil.release(null, ps, conn);
}
JOptionPane.showConfirmDialog(null, "修改成功");
}
public Student getStudentBySno(String sno){
// 将这些数据写入到数据库中
// 1、链接数据库
Connection conn = JDBCUtil.getConnection();
// 2、创建sql语句
String sql = "select * from student where sno=?";
// 3、创建一个PreparedStaement
PreparedStatement ps = null;
ResultSet rs = null;
try {
ps = conn.prepareStatement(sql);
ps.setString(1, sno);
rs = ps.executeQuery();
if (rs.next()) {
Student stu = new Student();
stu.setSno(rs.getString("sno"));
stu.setSname(rs.getString("sname"));
stu.setGender(rs.getString("gender"));
stu.setProfessinal(rs.getString("professional"));
stu.setClassis(rs.getString("classis"));
stu.setGrade(rs.getString("grade"));
stu.setIntime(rs.getDate("intime"));
return stu;
}
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
} finally {
JDBCUtil.release(rs, ps, conn);
}
return null;
}
public Vector getAllStudent() {
Vector result = new Vector();
// 讲这些数据写入到数据库中
// 1、链接数据库
Connection conn = JDBCUtil.getConnection();
// 2、创建sql语句
String sql = "select * from student";
// 3、创建一个PreparedStaement
PreparedStatement ps = null;
ResultSet rs = null;
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
Vector record = new Vector();
record.add(rs.getString("sno"));
record.add(rs.getString("sname"));
record.add(rs.getString("gender"));
record.add(rs.getString("professional"));
record.add(rs.getString("classis"));
record.add(rs.getString("grade"));
Date time = rs.getDate("intime");
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
record.add(sdf.format(time));
result.add(record);
}
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
} finally {
JDBCUtil.release(rs, ps, conn);
}
return result;
}
public Vector queryStudentByName(String name) {
Vector result = new Vector();
// 讲这些数据写入到数据库中
// 1、链接数据库
Connection conn = JDBCUtil.getConnection();
// 2、创建sql语句
String sql = "select * from student where sname like ?";
// 3、创建一个PreparedStaement
PreparedStatement ps = null;
ResultSet rs = null;
try {
ps = conn.prepareStatement(sql);
ps.setString(1, "%" + name + "%");
rs = ps.executeQuery();
while (rs.next()) {
Vector record = new Vector();
record.add(rs.getString("sno"));
record.add(rs.getString("sname"));
record.add(rs.getString("gender"));
record.add(rs.getString("professional"));
record.add(rs.getString("classis"));
record.add(rs.getString("grade"));
Date time = rs.getDate("intime");
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
record.add(sdf.format(time));
result.add(record);
}
} catch (SQLException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
}finally {
JDBCUtil.release(rs, ps, conn);
}
return result;
}
public Vector search(String name) {
Vector vector = getAllStudent();
Vector stuVector = null;
int i = 0;
for (; i < vector.size(); i++) {
stuVector = (Vector) vector.get(i);
if (stuVector.get(1).equals(name)) {
return stuVector;
}
}
if (i == vector.size()) {
return null;
}
return null;
}
}
JDBCTools {
/**
* 执行 SQL 语句, 使用 PreparedStatement
* @param sql
* @param args: 填写 SQL 占位符的可变参数
*/
public static void update(String sql, Object ... args){
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = JDBCTools.getConnection();
preparedStatement = connection.prepareStatement(sql);
for(int i = 0; i < args.length; i++){
preparedStatement.setObject(i + 1, args[i]);
}
preparedStatement.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally{
JDBCTools.releaseDB(null, preparedStatement, connection);
}
}