实体类的应用

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  1 /*
  2 * To change this template, choose Tools | Templates
  3 * and open the template in the editor.
  4 */
  5 package beans;
  6
  7 import java.io.Serializable;
  8 import java.util.Date;
  9 import javax.persistence.*;
10
11 /**
12 *
13 * @author teemu
14 */
15 @Entity
16 @Table(name = "PERSON")
17 public class Person implements Serializable {
18
19      private static final long serialVersionUID = 1L;
20     @Id
21     @GeneratedValue(strategy = GenerationType.AUTO)
22      private Long id;
23
24     @Column(name = "FIRST_NAME")
25      private String firstName;
26
27     @Column(name = "LAST_NAME")
28      private String lastName;
29
30     @Temporal(TemporalType.DATE)
31      private Date dateOfBirth;
32
33     @Embedded
34      private Address address;
35
36      public Person() {
37     }
38
39      public void setId(Long id) {
40          this.id = id;
41     }
42
43      public Long getId() {
44          return id;
45     }
46
47      public String getFirstName() {
48          return firstName;
49     }
50
51      public void setFirstName(String name) {
52         firstName = name;
53     }
54
55      public Address getAddress() {
56          return address;
57     }
58
59      public void setAddress(Address address) {
60          this.address = address;
61     }
62
63      public Date getDateOfBirth() {
64          return dateOfBirth;
65     }
66
67      public void setDateOfBirth(Date dateOfBirth) {
68          this.dateOfBirth = dateOfBirth;
69     }
70
71      public String getLastName() {
72          return lastName;
73     }
74
75      public void setLastName(String lastName) {
76          this.lastName = lastName;
77     }
78
79     @Override
80      public int hashCode() {
81          int hash = 0;
82         hash += (id != null ? id.hashCode() : 0);
83          return hash;
84     }
85
86     @Override
87      public boolean equals(Object object) {
88          // TODO: Warning - this method won't work in the case the id fields are not set
89          if (!(object instanceof Person)) {
90              return false;
91         }
92         Person other = (Person) object;
93          if (( this.id == null && other.id != null) || ( this.id != null && ! this.id.equals(other.id))) {
94              return false;
95         }
96          return true;
97     }
98
99     @Override
100      public String toString() {
101          return "beans.Person[ id=" + id + ", name: "+ firstName+" "+lastName+"]";
102     }
103 }

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1 /*
2 * To change this template, choose Tools | Templates
3 * and open the template in the editor.
4 */
5 package beans;
6
7 import javax.ejb.Stateless;
8 import javax.persistence.EntityManager;
9 import javax.persistence.PersistenceContext;
10
11 /**
12 *
13 * @author teemu
14 */
15 @Stateless
16 public class PersonFacade extends AbstractFacade<Person> {
17     @PersistenceContext(unitName = "EntityApplication-ejbPU")
18      private EntityManager em;
19
20     @Override
21      protected EntityManager getEntityManager() {
22          return em;
23     }
24
25      public PersonFacade() {
26          super(Person. class);
27     }
28
29 }

View Code

1 /*
2 * To change this template, choose Tools | Templates
3 * and open the template in the editor.
4 */
5 package beans;
6
7 import java.io.Serializable;
8 import javax.persistence.Column;
9 import javax.persistence.Embeddable;
10 import javax.persistence.Table;
11
12 /**
13 *
14 * @author teemu
15 */
16 @Embeddable
17 @Table(name = "ADDRESS")
18 public class Address implements Serializable {
19
20      private String street;
21      private String city;
22      private int zipCode;
23      private String country;
24
25     @Column(name = "STREET")
26      public String getStreet() {
27          return street;
28     }
29      public void setStreet(String street) {
30          this.street = street;
31     }
32
33     @Column(name = "CITY")
34      public String getCity() {
35          return city;
36     }
37      public void setCity(String city) {
38          this.city = city;
39     }
40
41     @Column(name = "STATE")
42      public int getZipCode() {
43          return zipCode;
44     }
45      public void setZipCode( int zipCode) {
46          this.zipCode = zipCode;
47     }
48
49     @Column(name = "COUNTRY")
50      public String getCountry() {
51          return country;
52     }
53      public void setCountry(String country) {
54          this.country = country;
55     }
56
57 }

View Code

1 /*
2 * To change this template, choose Tools | Templates
3 * and open the template in the editor.
4 */
5 package beans;
6
7 import java.util.List;
8 import javax.persistence.EntityManager;
9
10 /* *
11 *
12 * @author teemu
13 */
14 public abstract class AbstractFacade<T> {
15      private Class<T> entityClass;
16
17      public AbstractFacade(Class<T> entityClass) {
18          this.entityClass = entityClass;
19     }
20
21      protected abstract EntityManager getEntityManager();
22
23      public void create(T entity) {
24         getEntityManager().persist(entity);
25     }
26
27      public void edit(T entity) {
28         getEntityManager().merge(entity);
29     }
30
31      public void remove(T entity) {
32         getEntityManager().remove(getEntityManager().merge(entity));
33     }
34
35      public T find(Object id) {
36          return getEntityManager().find(entityClass, id);
37     }
38
39      public List<T> findAll() {
40         javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
41         cq. select(cq. from(entityClass));
42          return getEntityManager().createQuery(cq).getResultList();
43     }
44
45      public List<T> findRange( int[] range) {
46         javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
47         cq. select(cq. from(entityClass));
48         javax.persistence.Query q = getEntityManager().createQuery(cq);
49         q.setMaxResults(range[ 1] - range[ 0]);
50         q.setFirstResult(range[ 0]);
51          return q.getResultList();
52     }
53
54      public int count() {
55         javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
56         javax.persistence.criteria.Root<T> rt = cq. from(entityClass);
57         cq. select(getEntityManager().getCriteriaBuilder().count(rt));
58         javax.persistence.Query q = getEntityManager().createQuery(cq);
59          return ((Long) q.getSingleResult()).intValue();
60     }
61
62 }

View Code

  1 /*
  2 * To change this template, choose Tools | Templates
  3 * and open the template in the editor.
  4 */
  5 package servlets;
  6
  7 import beans.Address;
  8 import beans.Person;
  9 import beans.PersonFacade;
10 import java.io.IOException;
11 import java.io.PrintWriter;
12 import java.util.Calendar;
13 import javax.ejb.EJB;
14 import javax.servlet.ServletException;
15 import javax.servlet.annotation.WebServlet;
16 import javax.servlet.http.HttpServlet;
17 import javax.servlet.http.HttpServletRequest;
18 import javax.servlet.http.HttpServletResponse;
19
20 /**
21 *
22 * @author teemu
23 */
24 @WebServlet(name = "EntityServlet", urlPatterns = {"/EntityServlet"})
25 public class EntityServlet extends HttpServlet {
26
27     @EJB
28      private PersonFacade facade;
29
30      /**
31      * Processes requests for both HTTP
32      * <code>GET</code> and
33      * <code>POST</code> methods.
34      *
35      * @param request servlet request
36      * @param response servlet response
37      * @throws ServletException if a servlet-specific error occurs
38      * @throws IOException if an I/O error occurs
39       */
40      protected void processRequest(HttpServletRequest request, HttpServletResponse response)
41              throws ServletException, IOException {
42         response.setContentType("text/html;charset=UTF-8");
43         PrintWriter out = response.getWriter();
44
45         Person person1, person2;
46
47          try {
48               // create John Doe
49             person1 = new Person();
50             person1.setFirstName("John");
51             person1.setLastName("Doe");
52             Address addr = new Address();
53             addr.setStreet("Kidney Bean Drive 42");
54             addr.setCity("Beanville");
55             addr.setZipCode(12412);
56             addr.setCountry("Beantopia");
57             person1.setAddress(addr);
58             Calendar c = Calendar.getInstance();
59             c.set(1979, 3, 15);
60             person1.setDateOfBirth(c.getTime());
61
62              // create Jane Doe
63             person2 = new Person();
64             person2.setFirstName("Jane");
65             person2.setLastName("Doe");
66             addr = new Address();
67             addr.setStreet("Coffee Bean Avenue 42");
68             addr.setCity("Beantown");
69             addr.setZipCode(23567);
70             addr.setCountry("Beantopia");
71             person2.setAddress(addr);
72             c.set(1984, 7, 23);
73             person2.setDateOfBirth(c.getTime());
74
75              // persist John and Jane into database
76             facade.create(person1);
77             facade.create(person2);
78
79             out.println("<html>");
80             out.println("<head>");
81             out.println("<title>Entity Example</title>");
82             out.println("</head>");
83             out.println("<body>");
84
85              // search from database
86             Person foundPerson = facade.find(person1.getId());
87             out.println("<br>Result of finding John with his ID: " + foundPerson.toString());
88
89              // get and print all rows from the database
90             out.println("<br>Listing all Persons in the database: ");
91              for (Person p : facade.findAll()) {
92                 out.println("<br>"+p.toString());
93             }
94
95              // update Jane's first name
96             person2.setFirstName("Janet");
97             facade.edit(person2);
98             out.println("<br>Updated Jane: " + facade.find(person2.getId()).toString());
99
100              // remove John
101             facade.remove(person1);
102             out.println("<br>Removed John, printing all remaining Persons: ");
103              for (Person p : facade.findAll()) {
104                 out.println("<br>" + p.toString());
105             }
106
107             out.println("</body>");
108             out.println("</html>");
109         } finally {
110             out.close();
111         }
112     }
113
114      // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
115      /**
116      * Handles the HTTP
117      * <code>GET</code> method.
118      *
119      * @param request servlet request
120      * @param response servlet response
121      * @throws ServletException if a servlet-specific error occurs
122      * @throws IOException if an I/O error occurs
123       */
124     @Override
125      protected void doGet(HttpServletRequest request, HttpServletResponse response)
126              throws ServletException, IOException {
127         processRequest(request, response);
128     }
129
130      /**
131      * Handles the HTTP
132      * <code>POST</code> method.
133      *
134      * @param request servlet request
135      * @param response servlet response
136      * @throws ServletException if a servlet-specific error occurs
137      * @throws IOException if an I/O error occurs
138       */
139     @Override
140      protected void doPost(HttpServletRequest request, HttpServletResponse response)
141              throws ServletException, IOException {
142         processRequest(request, response);
143     }
144
145      /**
146      * Returns a short description of the servlet.
147      *
148      * @return a String containing servlet description
149       */
150     @Override
151      public String getServletInfo() {
152          return "Short description";
153     } // </editor-fold>
154 }

View Code

1 <%--
2     Document   : index
3     Created on : Mar 20, 2012, 11: 06: 47 AM
4     Author     : teemu
5 --%>
6
7 <%@page contentType= " text/html " pageEncoding= " UTF-8 "%>
8 <!DOCTYPE html>
9 <html>
10     <head>
11         <meta http-equiv= " Content-Type " content= " text/html; charset=UTF-8 ">
12         <title>JSP Page</title>
13     </head>
14     <body>
15         <h1><a href= " EntityServlet ">Click to open the servlet</a></h1>
16     </body>
17 </html>

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实体类的应用

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