■AddMember.java            

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * @author student
 *
 */
public class AddMember extends HttpServlet {
    public void doGet(HttpServletRequest req, HttpServletResponse res) 
        throws ServletException, IOException {
        // パラメーターの受け取り
        String name = req.getParameter("name");
        if(name == null || name.length() == 0) {
            throw new ServletException();
        }
        
        // セッションオブジェクトの取得
        HttpSession session = req.getSession(true);
        
        // Result オブジェクトをセッションオブジェクトに設定
        Circle01 circle = new Circle01();
        Result01 result;
        try {
            result = circle.addMember(name);
        } catch (CircleException e) {
            throw new ServletException();
        }
        session.setAttribute("result", result);
        
        // JSP にフォーワード
        getServletContext().getRequestDispatcher("/jsp/circle01.jsp").forward(req, res);
        
    }

    public void doPost(HttpServletRequest req, HttpServletResponse res) 
        throws ServletException, IOException {
        doGet(req, res);
    }
}
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■Circle01.java            

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

public class Circle01 {

    private Map members = new TreeMap();

    private int currentMaxMemberCode = 0;

    private DecimalFormat df = new DecimalFormat("0000");

    public Result01 addMember(String name)  throws CircleException {
        Result01 ret = new Result01();
//        currentMaxMemberCode++;
        String code = "ME" + df.format(++currentMaxMemberCode);
        members.put(code, new Member01(code, name));
        ret.addInfo(createInfoElement("会員番号", code));
        return ret;
    }

    public Result01 removeMember(String code) throws NoMemberException {
        Result01 ret = new Result01();
        Member01 member = (Member01) members.get(code);
        if (member == null) {
            ret.setCode(Result01.NO_MEMBER);
            throw new NoMemberException();
//            return ret;
        }
        members.remove(code);
        return ret;
    }

    public Result01 showMembers()  throws NoMemberException {
        if (members.size() == 0) {
            throw new NoMemberException();
        }
        Result01 ret = new Result01();
        ret.addInfo(createInfoElement("会員番号", "名前"));
        Iterator it = members.values().iterator();
        while (it.hasNext()) {
            Member01 member = (Member01) it.next();
            ret.addInfo(createInfoElement(member.getCode(), member.getName()));
        }
        return ret;
    }

    /**
     * @param string
     * @param string2
     * @return
     */
    private List createInfoElement(String string1, String string2) {
        List info = new ArrayList();
        info.add(string1);
        info.add(string2);
        return info;
    }
}
------------------------------------------------------ 

■CircleException.java            

/**
 * @author student
 */
public class CircleException extends Exception {

}
------------------------------------------------------ 

■Member01.java            

/**
 * 会員を管理します。
 * @author student
 * @version
 * @since
 *
 * TODO この生成された型コメントのテンプレートを変更するには次へジャンプ:
 * ウィンドウ - 設定 - Java - コード・スタイル - コード・テンプレート
 */
public class Member01 {
 
    private String code;
     
    private String name;
     
     
    /**
     * @param name
     */
    public Member01(String name) {
        this.name = name;
    }
    
    /**
     * @param code 会員番号
     * @param name 会員名
     */
    public Member01(String code, String name) {
        this.code = code;
        this.name = name;
    }
    /**
     * @return code を戻します。
     */
    public String getCode() {
        return code;
    }
    /**
     * @param code code を設定。
     */
    private void setCode(String code) {
        this.code = code;
    }
    /**
     * @return name を戻します。
     */
    public String getName() {
        return name;
    }
    /**
     * @param name name を設定。
     */
    private void setName(String name) {
        this.name = name;
    }
}
 
------------------------------------------------------ 

■NoMemberException.java            

/**
 * @author student
 *
 */
public class NoMemberException extends CircleException {

}
------------------------------------------------------ 

■Result01.java            

import java.util.LinkedList;
import java.util.List;

public class Result01 {
    public static final int OK = 0;
    public static final int NO_MEMBER = -1;
    
    private int code = OK;
    private List info = new LinkedList();
    
    
    /**
     * @return code を戻します。
     */
    public int getCode() {
        return code;
    }
    /**
     * @param code code を設定。
     */
    public void setCode(int code) {
        this.code = code;
    }
    /**
     * @return info を戻します。
     */
    public List getInfo() {
        return info;
    }
    /**
     * @param info info を設定。
     */
    public void setInfo(List info) {
        this.info = info;
    }
    /**
     * @param row info を設定。
     */
    public void addInfo(List row) {
        this.info.add(row);
    }
}
 
------------------------------------------------------ 

■addMember.jsp            

<%@ page contentType="text/html;charset=EUC-JP" %>
<html>
<body>
<table>
<tr>
<td><a href="/webcircle/jsp/addMember.jsp">会員登録</a></td>
<td rowspan="3">

<form method="GET" action="/webcircle/servlet/AddMember">
<p>名前：<input type="text" name="name"/></p>
<p><input type="submit" value="登録"/></p>
</form>

</td>
</tr>

<tr>
<td><a href="/webcircle/jsp/removeMember.jsp">会員削除</a></td>
</tr>

<tr>
<td><a href="/webcircle/jsp/showMembers.jsp">会員照会</a></td>
</tr>

</table>
</body>
</html>
------------------------------------------------------ 

■circle01.jsp            

<%@ page contentType="text/html;charset=EUC-JP" %>
<html>
<body>
<table>
<tr>
<td><a href="/webcircle/jsp/addMember.jsp">会員登録</a></td>
<td rowspan="3">
    ${result.info}
</td>
</tr>

<tr>
<td><a href="/webcircle/jsp/removeMember.jsp">会員削除</a></td>
</tr>

<tr>
<td><a href="/webcircle/jsp/showMembers.jsp">会員照会</a></td>
</tr>

</table>
</body>
</html>
------------------------------------------------------ 

■web.xml            

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app
    version="2.4"
    xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
                        http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
>
    <servlet>
        <servlet-name>invoker</servlet-name>
        <servlet-class>
          org.apache.catalina.servlets.InvokerServlet
        </servlet-class>
        <init-param>
            <param-name>debug</param-name>
            <param-value>0</param-value>
        </init-param>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>invoker</servlet-name>
        <url-pattern>/servlet/*</url-pattern>
    </servlet-mapping>
</web-app>
------------------------------------------------------