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サンプルプログラム

UserTable?.java (Entity Bean)

package com.mycompany.sampleweb;

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;

@Entity
@Table(name = "user_table")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "UserTable.findAll", query = "SELECT u FROM UserTable u ORDER BY u.id"),
    @NamedQuery(name = "UserTable.countAll", query = "SELECT COUNT(u.id) FROM UserTable u"),
    @NamedQuery(name = "UserTable.findById", query = "SELECT u FROM UserTable u WHERE u.id = :id"),
    @NamedQuery(name = "UserTable.findByName", query = "SELECT u FROM UserTable u WHERE u.name = :name")})
public class UserTable implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Long id;
    @Size(max = 255)
    @Column(name = "name")
    private String name;

    public UserTable() {
    }

    public UserTable(Long id) {
        this.id = id;
    }

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof UserTable)) {
            return false;
        }
        UserTable other = (UserTable) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "com.mycompany.sampleweb.UserTable[ id=" + id + " ]";
    }
    
}

Paging.java (Servlet)

package com.mycompany.sampleweb;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import javax.persistence.TypedQuery;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "Paging", urlPatterns = {"/Paging"})
public class Paging extends HttpServlet {

    @PersistenceContext(unitName = "appPU")
    private EntityManager em;
        
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        int start = 0;
        try {
            start = Integer.parseInt(request.getParameter("start"));
        } catch (NumberFormatException | NullPointerException ex) {
        }
        
        // 全件検索
        TypedQuery findQuery = em.createNamedQuery("UserTable.findAll", UserTable.class);
        findQuery.setFirstResult(start);
        findQuery.setMaxResults(20);
        List<UserTable> result = findQuery.getResultList();
        
        // 件数
        Query countQuery = em.createNamedQuery("UserTable.countAll");
        long count = (Long) countQuery.getSingleResult();
        
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            /* TODO output your page here. You may use following sample code. */
            out.println("<!DOCTYPE html>");
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet Paging</title>");            
            out.println("</head>");
            out.println("<body>");
            out.println("<table border=\"1\"><tbody>");
            for (UserTable user : result) {
                out.println(String.format("<tr><td>%s</td><td>%s</td></tr>", user.getId(), user.getName()));
            }
            out.println("</tbody></table>");
            if (start - 20 >= 0) {
                out.print(String.format("<a href=\"Paging?start=%s\"><</a>", start - 20));            
            }
            out.print(String.format("[%s/%s]", start, count));            
            if (start + 20 < count) {
                out.print(String.format("<a href=\"Paging?start=%s\">></a>", start + 20));            
            }
            out.println("</body>");
            out.println("</html>");
        }
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}

Java#Glassfish


添付ファイル: filepaging.png 310件 [詳細]

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Last-modified: 2014-04-23 (水) 01:49:47 (962d)
ISBN10
ISBN13
9784061426061