第一步：webroot/web-inf下简历str.tld文件
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd"> 3 <taglib> <!-- 自定义库标签的根 --> 4 <tlibversion>1.2</tlibversion> <!-- 版本号 --> 5 <jspversion>1.1</jspversion> <!-- JSP版本号 --> 6 <shortname>stu</shortname> <!-- prefix="stu"标签名称--> 7 <uri>StudentTags</uri> <!-- uri="StudentTags" 外界导入标签时，认识的名字，很重要。--> 8 9 <tag> 10 <name>selectAll</name> <!-- 标签名称 --> 11 <tagclass>com.bjsxt.sxf.tag.SeclectAllSt</tagclass> <!-- 对应的java类的全路径 --> 12 </tag> 13 14 <!-- 有属性的标签，可以有多个属性 <attribute>并列 --> 15 <tag> 16 <name>selectBySex</name> <!-- 标签名称 --> 17 <tagclass>com.bjsxt.sxf.tag.SeclectStBySex</tagclass> 18 <attribute> <!-- 对应标签的属性。 --> 19 <name>sex</name> 20 <required>true</required> <!-- 是必需写的属性，即没有写属性标签不能被正常使用 --> 21 </attribute> 22 </tag> 23 <!-- 按班级学生id查询出班级集合，存放到属性var指定的变量中，然后利用s标签的迭代标签，将var指定的变量存放的学生集合遍历出来 --> 24 <tag> 25 <name>selectByClassId</name> <!-- 标签名称 --> 26 <tagclass>com.bjsxt.sxf.tag.MyTag</tagclass> <!-- 对应的java类的全路径 --> 27 <body-content>JSP</body-content><!-- 如果不需要标签体则设置empty，反之设定jsp，内部可以运行jsp所有的语法 --> 28 <attribute> 29 <name>classId</name><!--指定属性名 和标签java类一致--> 30 <required>true</required><!--该属性是否是必须，如果非必须没设置则为空。 --> 31 <rtexprvalue>true</rtexprvalue><!-- 该属性能不能动态使用表达式为该属性赋值 true可以 false不可以 使用脚本和EL表达式来获取动态的值 --> 32 </attribute> 33 <attribute> 34 <name>var</name> 35 <required>true</required> 36 <rtexprvalue>false</rtexprvalue> 37 </attribute> 38 <attribute> 39 <name>num</name> 40 <required>false</required> 41 <rtexprvalue>false</rtexprvalue> 42 </attribute> 43 </tag> 44 <!-- 自定义的myif标签 --> 45 <tag> 46 <name>myif</name> 47 <tagclass>com.bjsxt.sxf.tag.MyIfTag</tagclass> 48 <bodycontent>JSP</bodycontent> 49 <attribute> 50 <name>flag</name> 51 <required>true</required> 52 <rtexprvalue>true</rtexprvalue> 53 </attribute> 54 <attribute> 55 <name>condition</name> 56 <required>true</required> 57 <rtexprvalue>true</rtexprvalue> 58 </attribute> 59 </tag> 60 <!-- 自定义的myelseif标签 --> 61 <tag> 62 <name>myelseif</name> 63 <tagclass>com.bjsxt.sxf.tag.MyElseIfTag</tagclass> 64 <bodycontent>JSP</bodycontent> 65 <attribute> 66 <name>flag</name> 67 <required>true</required> 68 <rtexprvalue>true</rtexprvalue> 69 </attribute> 70 <attribute> 71 <name>condition</name> 72 <required>true</required> 73 <rtexprvalue>true</rtexprvalue> 74 </attribute> 75 </tag> 76 <!-- 自定义的myelse标签 --> 77 <tag> 78 <name>myelse</name> 79 <tagclass>com.bjsxt.sxf.tag.MyElseTag</tagclass> 80 <bodycontent>JSP</bodycontent> 81 </tag> 82 83 </taglib>
第二步：建立标签类
1 package com.bjsxt.sxf.tag;
2
3 import javax.servlet.http.HttpServletRequest;
4 import javax.servlet.http.HttpServletResponse;
5
6 import org.apache.struts2.components.Component;
7 import org.apache.struts2.views.jsp.ComponentTagSupport;
8
9 import com.bjsxt.sxf.tag.compant.MyIfComponent;
10 import com.opensymphony.xwork2.util.ValueStack;
11 /**
12 * myif的标签类
13 * @ClassName: MyIfTag
14 * @Description: TODO(这里用一句话描述这个类的作用)
15 * @author 尚晓飞
16 * @date 2014-10-22 下午3:46:45
17 *
18 */
19 public class MyIfTag extends ComponentTagSupport {
20 private String flag;//if判断的标示
21 private String condition;//可以传递的多个参数代表
22
23 //生成标签逻辑类的对象。多态。父类引用，指向子类对象
24 @Override
25 public Component getBean(ValueStack arg0, HttpServletRequest arg1,
26 HttpServletResponse arg2) {
27 return new MyIfComponent(arg0, arg1,arg2);
28 }
29
30 //给逻辑类的属性赋值
31 @Override
32 protected void populateParams() {
33 super.populateParams();
34 MyIfComponent myIfComponent=(MyIfComponent) getComponent();
35 myIfComponent.setFlag(flag);
36 myIfComponent.setCondition(condition);
37 }
38
39 public String getFlag() {
40 return flag;
41 }
42
43 public void setFlag(String flag) {
44 this.flag = flag;
45 }
46
47 public String getCondition() {
48 return condition;
49 }
50
51 public void setCondition(String condition) {
52 this.condition = condition;
53 }
54
55
56 }
57
58
59 package com.bjsxt.sxf.tag;
60
61 import javax.servlet.http.HttpServletRequest;
62 import javax.servlet.http.HttpServletResponse;
63
64 import org.apache.struts2.components.Component;
65 import org.apache.struts2.views.jsp.ComponentTagSupport;
66
67 import com.bjsxt.sxf.tag.compant.MyElseIfComponent;
68 import com.opensymphony.xwork2.util.ValueStack;
69 /**
70 * myelseif的标签类
71 * @ClassName: MyElseIfTag
72 * @Description: TODO(这里用一句话描述这个类的作用)
73 * @author 尚晓飞
74 * @date 2014-10-22 下午3:47:59
75 *
76 */
77 public class MyElseIfTag extends ComponentTagSupport{
78 private String flag;//elsif判断的标示
79 private String condition;//可以传递的多个参数代表
80
81
82 //返回该标签逻辑类的对象
83 @Override
84 public Component getBean(ValueStack arg0, HttpServletRequest arg1,
85 HttpServletResponse arg2) {
86
87 return new MyElseIfComponent(arg0, arg1, arg2);
88 }
89
90 //给该标签逻辑类对象赋值
91 @Override
92 protected void populateParams() {
93 super.populateParams();
94 MyElseIfComponent myElseIfComponent=(MyElseIfComponent) getComponent();
95 myElseIfComponent.setFlag(flag);
96 myElseIfComponent.setCondition(condition);
97 }
98 public String getFlag() {
99 return flag;
100 }
101 public void setFlag(String flag) {
102 this.flag = flag;
103 }
104 public String getCondition() {
105 return condition;
106 }
107 public void setCondition(String condition) {
108 this.condition = condition;
109 }
110
111
112 }
113
114
115 package com.bjsxt.sxf.tag;
116
117 import javax.servlet.http.HttpServletRequest;
118 import javax.servlet.http.HttpServletResponse;
119
120 import org.apache.struts2.components.Component;
121 import org.apache.struts2.views.jsp.ComponentTagSupport;
122
123 import com.bjsxt.sxf.tag.compant.MyElseComponent;
124 import com.opensymphony.xwork2.util.ValueStack;
125 /**
126 * 自定义的else标签
127 * @ClassName: MyElse
128 * @Description: TODO(这里用一句话描述这个类的作用)
129 * @author 尚晓飞
130 * @date 2014-10-22 下午2:24:30
131 *
132 */
133 public class MyElseTag extends ComponentTagSupport{
134
135 @Override
136 public Component getBean(ValueStack arg0, HttpServletRequest arg1,
137 HttpServletResponse arg2) {
138 // TODO Auto-generated method stub
139 return new MyElseComponent(arg0, arg1, arg2);
140 }
141
142 @Override
143 protected void populateParams() {
144 // TODO Auto-generated method stub
145 super.populateParams();
146 }
147
148
149 }
第三步：建立标签逻辑类
1 package com.bjsxt.sxf.tag.compant;
2
3 import java.io.Writer;
4
5 import javax.servlet.http.HttpServletRequest;
6 import javax.servlet.http.HttpServletResponse;
7
8 import org.apache.struts2.components.Component;
9
10 import com.opensymphony.xwork2.util.ValueStack;
11
12 /**
13 * myif标签逻辑类 没有@的标签注解，好像不影响，
14 * @ClassName: MyIfComponent
15 * @Description: TODO(这里用一句话描述这个类的作用)
16 * @author 尚晓飞
17 * @date 2014-10-22 下午3:49:40
18 *
19 */
20 public class MyIfComponent extends Component {
21 protected String flag;
22 protected String condition;
23 public static final String MyANSWER = "struts.if.answer";
24 protected Boolean answer;
25
26
27 public MyIfComponent(ValueStack stack,HttpServletRequest req,HttpServletResponse resp) {
28 super(stack);
29 }
30
31
32 //标签运行开始执行
33 @Override
34 public boolean start(Writer writer) {
35 answer = (Boolean) findValue(flag, Boolean.class);
36 if (answer == null) {
37 answer = Boolean.FALSE;
38 }
39
40 stack.getContext().put(MyANSWER, answer);
41 boolean flg=answer.booleanValue();
42 return flg;
43 }
44
45 //标签运行结束执行
46 @Override
47 public boolean end(Writer writer, String body) {
48 stack.getContext().put(MyANSWER, answer);
49 boolean fd=super.end(writer, body);
50 return fd;
51 }
52 public String getFlag() {
53 return flag;
54 }
55
56 public void setFlag(String flag) {
57 this.flag = flag;
58 }
59
60 public String getCondition() {
61 return condition;
62 }
63
64 public void setCondition(String condition) {
65 this.condition = condition;
66 }
67
68
69 }
70
71
72 package com.bjsxt.sxf.tag.compant;
73
74 import java.io.Writer;
75 import java.util.Map;
76
77 import javax.servlet.http.HttpServletRequest;
78 import javax.servlet.http.HttpServletResponse;
79
80 import org.apache.struts2.components.Component;
81
82 import com.opensymphony.xwork2.util.ValueStack;
83
84 /**
85 * myelseif的逻辑类
86 * @ClassName: MyElseIfComponent
87 * @Description: TODO(这里用一句话描述这个类的作用)
88 * @author 尚晓飞
89 * @date 2014-10-22 下午3:50:49
90 *
91 */
92 public class MyElseIfComponent extends Component {
93 protected String flag;
94 protected String condition;
95 public static final String MyANSWER = "struts.myelseif.answer";
96 protected Boolean answer;
97
98 public MyElseIfComponent(ValueStack stack,HttpServletRequest req,HttpServletResponse resp) {
99 super(stack);
100 // TODO Auto-generated constructor stub
101 }
102
103
104 @Override
105 public boolean start(Writer writer) {
106 boolean myflag=false;
107 //获取值栈
108 Map context = stack.getContext();
109 //先从值栈中获取if标签的flag的值
110 Boolean ifResult = (Boolean) context.get(MyIfComponent.MyANSWER);
111 //如果存在elseif 则需要获取该值
112 Boolean elseIfResult=(Boolean) context.get(MyElseIfComponent.MyANSWER);
113 context.remove(MyIfComponent.MyANSWER);
114 context.remove(MyElseIfComponent.MyANSWER);
115
116 //判断是否存在if=true的情况
117 if(ifResult!=null&&ifResult==true){
118 //if=true
119 myflag=false;
120 }else{
121 //if=false
122 //是否存在else if
123 if(elseIfResult!=null&&elseIfResult==true){
124 //else if=true;
125 myflag=false;
126 }else{
127 //else if=false或者不存在上个else if
128 answer = (Boolean) findValue(flag, Boolean.class);
129 if (answer == null) {
130 answer = Boolean.FALSE;
131 }
132 stack.getContext().put(MyANSWER, answer);
133 myflag=answer.booleanValue();
134 }
135 }
136 return myflag;
137 }
138 @Override
139 public boolean end(Writer writer, String body) {
140 stack.getContext().put(MyANSWER, answer);
141 return super.end(writer, body);
142 }
143 public String getFlag() {
144 return flag;
145 }
146 public void setFlag(String flag) {
147 this.flag = flag;
148 }
149 public String getCondition() {
150 return condition;
151 }
152 public void setCondition(String condition) {
153 this.condition = condition;
154 }
155 public Boolean getAnswer() {
156 return answer;
157 }
158 public void setAnswer(Boolean answer) {
159 this.answer = answer;
160 }
161
162
163 }
164
165
166 package com.bjsxt.sxf.tag.compant;
167
168 import java.io.Writer;
169 import java.util.Map;
170
171 import javax.servlet.http.HttpServletRequest;
172 import javax.servlet.http.HttpServletResponse;
173
174 import org.apache.struts2.components.Component;
175
176 import com.opensymphony.xwork2.util.ValueStack;
177
178 public class MyElseComponent extends Component{
179
180 /**
181 * myelse的逻辑类
182 *
183 * @Title: EncodingRequestWrapper
184 * @Description: 构造函数
185 * @param stack
186 * @param req
187 * @param response
188 * @author 尚晓飞
189 * @date 2014-10-22 下午3:51:24
190 */
191 public MyElseComponent(ValueStack stack,HttpServletRequest req,HttpServletResponse response) {
192 super(stack);
193 }
194 //Myelse标签运行开始
195 @Override
196 public boolean start(Writer writer) {
197 boolean myflg=false;
198 //获取值栈
199 Map context = stack.getContext();
200 //获取if的值
201 Boolean ifResult = (Boolean) context.get(MyIfComponent.MyANSWER);
202 //获取else的值
203 Boolean elseifResult=(Boolean) context.get(MyElseIfComponent.MyANSWER);
204 //移除值栈中的值
205 context.remove(MyIfComponent.MyANSWER);
206 context.remove(MyElseIfComponent.MyANSWER);
207
208 //判断是否存在if
209 if(ifResult!=null&&ifResult==true){
210 //存在if，并且为true;
211 myflg=false;
212 }else{
213 //if为false
214 //判断elseif是否存在
215 if(elseifResult!=null&&elseifResult==true){
216 //存在elseif标签,且==true
217 myflg=false;
218 }else{
219 //不存在elseif标签或者为elseif标签==false或者if标签为false
220 myflg=true;
221 }
222 }
223
224
225 return myflg;
226 }
227
228 @Override
229 public boolean end(Writer writer, String body) {
230 // TODO Auto-generated method stub
231 boolean d=super.end(writer, body);
232 return d;
233 }
234
235
236
237
238 }
第四步：测试页面
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <%@ taglib uri="StudentTags" prefix="stu" %> 3 <%@ taglib uri="/struts-tags" prefix="s"%> 4 <% 5 String path = request.getContextPath(); 6 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 7 %> 8 9 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 10 <html> 11 <head> 12 </head> 13 14 <body> 15 This is my JSP page. <br> 16 <a href="<%=request.getContextPath()%>/StudentAction!reportStudent.action">班级表单下载</a> 17 <h1>查询出所有学生的标签效果</h1> 18 <stu:selectAll></stu:selectAll> 19 <h1>查询出指定性别的学生的标签效果</h1> 20 <stu:selectBySex sex="男"></stu:selectBySex> 21 <h1>查询出指定班级id的学生集合的标签效果</h1> 22 <stu:selectByClassId var="students" classId="1" > 23 <table border="2"> 24 <tr> 25 <td>id</td> 26 <td>姓名</td> 27 <td>性别</td> 28 <td>班级</td> 29 </tr> 30 <s:iterator value="#students" var="stu"> 31 <tr> 32 <td><s:property value="#stu.id"/></td> 33 <td><s:property value="#stu.name"/></td> 34 <td><s:property value="#stu.sex"/></td> 35 <td><s:property value="#stu.classRoom.name"/></td> 36 </tr> 37 </s:iterator> 38 </table> 39 </stu:selectByClassId> 40 41 <h1>我是中国人</h1> 42 <stu:myif flag="1==3" condition="shangxiaofei"> 43 <h1>myif是true</h1> 44 </stu:myif> 45 <stu:myelseif flag="1==2" condition="first"> 46 <h1>第一个myelseif是false</h1> 47 </stu:myelseif> 48 <stu:myelseif flag="1==1" condition="sencod"> 49 <h1>第二个myelseif是true</h1> 50 </stu:myelseif> 51 <stu:myelse> 52 <h1>false</h1> 53 </stu:myelse> 54 </body> 55 56 </html>
第五步:效果图
时间： 2024-10-20 08:14:47