深圳尚学堂:干货来啦!JAVA常用代码(三)

//15.Java Mail

// 发送Mail

protected String msgRecIp = "hxydream@163.com";

protected String msgSubject = "babytree";

protected String msgCc = "nobody@erewhon.com";

protected String msgBody = "test body";

protected Session session;

protected Message msg;

public void doSend() {

// 创建属性文件

Properties props = new Properties();

props.put("mail.smtp.host", "mailhost");

// 创建Session对象

session = Session.getDefaultInstance(props, null);

session.setDebug(true);

msg = new MimeMessage(session); // 创建邮件

msg. setFrom(new InternetAddress("nobody@host.domain"));

InternetAddress toAddr = new InternetAddress(msgRecIp);

msg.addRecipient(Message.RecipientType.TO, toAddr);

InternetAddress ccAddr = new InternetAddress(msgCc);

msg.addRecipient(Message.RecipientType.CC, ccAddr);

msg.setSubject(msgSubject);

msg.setText(msgBody);

Transport.send(msg);

}

// 发送MIME邮件

Multipart mp = new MimeMultipart();

BodyPart textPart = new MimeBodyPart();

textPart.setText(message_body); // 设置类型"text/plain"

BodyPart pixPart = new MimeBodyPart();

pixPart.setContent(html_data, "text/html");

mp.addBodyPart(textPart);

mp.addBodyPart(pixPart);

mesg.setContent(mp);

Transport.send(mesg);

// 读Mail

Store store = session.getStore(protocol);

store.connect(host, user, password);

Folder rf;

rf = store.getFolder(root);

rf = store.getDefaultFolder();

rf.open(Folder.READ_WRITE);

//16. 数据库访问

// JDO

Properties p = new Properties();

p.load(new FileInputStream("jdo.properties"));

PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory(p);

PersistenceManager pm = pmf.getPersistenceManager();

// 提交数据

pm.currentTransaction().begin();

if (o instanceof Collection) {

pm.makePersistentAll((Collection) o);

} else {

pm.makePersistent(o);

}

pm.currentTransaction().commit();

pm.close();

// 取出数据

Object[] data = new Object[3];

pm.retrieveAll(data);

for (int i = 0; i < data.length; i++) {

System.out.println(data[i]);

}

pm.close();

// 数据操作

Class clz = Class.forName("oracle.jdbc.driver.OracleDriver");

String dbUrl = "jdbc:oracle:thin:@192.168.0.23:1521#:nms";

Connection conn = DriverManager.getConnection(dbUrl, "su", "1234");

Statement stmt = conn.createStatement();

ResultSet rs = stmt.executeQuery("select * from pmtable");

while (rs.next()) {

String name = rs.getString(1);

String otherName = rs.getString("name");

}

// 使用PreparedStatement提高性能，除了查询，都使用executeUpdate执行操作

PreparedStatement pstmt = conn.prepareStatement("select * from pmtable where name = ?");

pstmt.setString(1, "sean");

ResultSet rs = pstmt.executeQuery();

// 调用存储过程

CallableStatement cs = conn.prepareCall("{ call ListDefunctUsers }");

ResultSet rs = cs.executeQuery();

// 显示数据库表信息

DatabaseMetaData meta = conn.getMetaData();

meta.getDatabaseProductName();

meta.getDatabaseProductVersion();

meta.getDefaultTransactionIsolation();

/*

17.XML

SAX: 在读取文档提取相应的标记事件(元素起始、元素结束、文档起始)

DOM: 在内存中构造与文档中元素相应的树，可以遍历、搜索、修改

DTD: 验证文档是否正确

JAXP: 用于XML处理的Java API

Castor: 开源项目，用于Java对象与XML映射

*/

// 从对象中生成XML

private final static String FILENAME = "serial.xml";

public static void main(String[] args) throws IOException {

String a = "hard work and best callback";

new SerialDemoXML().write(a);

new SerialDemoXML().dump();

}

public void write(Object obj) throws IOException {

XMLEncoder os = new XMLEncoder(new BufferedOutputStream(new FileOutputStream(FILENAME)));

os.writeObject(obj);

os.close();

}

public void dump() throws IOException {

XMLDecoder out = new XMLDecoder(new BufferedInputStream(new FileInputStream(FILENAME)));

System.out.println(out.readObject());

out.close();

}

serial.xml格式内容如下:

<?xml version="1.0" encoding="UTF-8"?>

<java version="1.6.0_02" class="java.beans.XMLDecoder">

<string>hard work and best callback</string>

</java>

控制台输出

hard work and best callback

// XSLT转换XML

XSLT可以用来对输出格式进行各种控制

Transformer tx = TransformerFactory.newInstance().newTransformer(new StreamSource("people.xml"));

tx.transform(new StreamSource("people.xml"), new StreamResult("people.html"));

// 用SAX解析XML - 主要用于查找关键元素，不用全文遍历

public SaxLister() throws SAXException, IOException {

XMLReader parser = XMLReaderFactory.createXMLReader("org.apache.xerces.parsers.SAXParser");

parser.setContentHandler(new PeopleHandler());

parser.parse("C:\\StudySource\\javacooksrc2\\xml\\people.xml");

}

class PeopleHandler extends DefaultHandler {

boolean parent = false;

boolean kids = false;

public void startElement(String nsURI, String localName, String rawName, Attributes attr) throws SAXException {

System.out.println("startElement: " + localName + "," + rawName);

if (rawName.equalsIgnoreCase("name"))

parent = true;

if (rawName.equalsIgnoreCase("children"))

kids = true;

}

public void characters(char[] ch, int start, int length) {

if (parent) {

System.out.println("Parent: " + new String(ch, start, length));

parent = false;

} else if (kids) {

System.out.println("Children: " + new String(ch, start, length));

kids = false;

}

}

public PeopleHandler() throws SAXException {

super();

}

}

// DOM解析XML - 遍历整个树

String uri = "file:" + new File("C:\\StudySource\\javacooksrc2\\xml\\people.xml").getAbsolutePath();

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

DocumentBuilder builder = factory.newDocumentBuilder();

Document doc = builder.parse(uri);

NodeList nodes = doc.getChildNodes();

for (int i = 0; i < nodes.getLength(); i++) {

Node n = nodes.item(i);

switch (n.getNodeType()) {

case Node.ELEMENT_NODE:

// todo

break;

case Node.TEXT_NODE:

// todo

break;

}

}

// 使用DTD或者XSD验证

定义好DTD或XSD文件

XmlDocument doc = XmlDocument.createXmlDocument(uri, true);

// 用DOM生成XML

DocumentBuilderFactory fact = DocumentBuilderFactory.newInstance();

DocumentBuilder parser = fact.newDocumentBuilder();

Document doc = parser.newDocument();

Node root = doc.createElement("Poem");

doc.appendChild(root);

Node stanza = doc.createElement("Stanza");

root.appendChild(stanza);

Node line = doc.createElement("Line");

stanza.appendChild(line);

line.appendChild(doc.createTextNode("Once, upon a midnight dreary"));

line = doc.createElement("Line");

stanza.appendChild(line);

line.appendChild(doc.createTextNode("While I pondered, weak and weary"));

//18.RMI

a. 定义客户端与服务器之间的通信接口

public interface RemoteDate extends Remote {

public Date getRemoteDate() throws RemoteException;

public final static String LOOKUPNAME = "RemoteDate";

}

b. 编写RMI服务器

public class RemoteDateImpl extends UnicastRemoteObject implements RemoteDate {

public RemoteDateImpl() throws RemoteException {

super();

}

public Date getRemoteDate() throws RemoteException {

return new Date();

}

}

RemoteDateImpl im = new RemoteDateImpl();

System.out.println("DateServer starting...");

Naming.rebind(RemoteDate.LOOKUPNAME, im);

System.out.println("DateServer ready.");

c. 运行rmic生成stub

javac RemoteDateImpl.java

rmic RemoteDateImpl

d. 编写客户端

netConn = (RemoteDate)Naming.lookup(RemoteDate.LOOKUPNAME);

Date today = netConn.getRemoteDate();

System.out.println(today.toString());

e. 确保RMI注册表运行

rmiregistry

f. 启动服务器

java RemoteDateImpl

g. 运行客户端

java DateClient