jsp tld 的tag 自定義标簽擴充

引入方式

1. <%@ taglib prefix="bgt" uri="/WEB-INF/tlds/bgt.tld" %>

寫法示例如下：

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

2. <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"

3. "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">

4. <taglib>

5. <tlib-version>1.0</tlib-version>

6. <jsp-version>2.0</jsp-version>

7. <short-name>bgt</short-name>

8. <!-- backGroundTag -->

9. <uri>http://www.sdyy.tag</uri>

10. <tag>

11. <name>hasUrlPerm</name>

12. <tag-class>com.sdyy.common.tags.HasUrlPermissionTag</tag-class>

13. <attribute>

14. <name>link</name>

15. <required>false</required>

16. <rtexprvalue>true</rtexprvalue><!-- 是否支援惡劣表達式 -->

17. <type>java.lang.String</type>

18. <description>示例：acApplication/forMain.do</description>

19. </attribute>

21. </tag>

22. </taglib>

A、【判斷标簽】HasUrlPermissionTag标簽是一個判斷标簽，通過該标簽來決定标簽包裹的内容是否顯示，寫法如下：

1. package com.sdyy.common.tags;

5. import javax.servlet.http.HttpServletRequest;

6. import javax.servlet.jsp.JspException;

7. import javax.servlet.jsp.tagext.BodyTagSupport;

9. import com.sdyy.common.spring.interceptor.PermissionInterceptor;

11. public class HasUrlPermissionTag extends BodyTagSupport {

13. private String link;// acApplication/forMain.do

15. @Override

16. public int doStartTag() throws JspException { // 在标簽開始處出發該方法

18. HttpServletRequest request=(HttpServletRequest) pageContext.getRequest();

19. //擷取session中存放的權限

21. //判斷是否有權限通路

22. if (PermissionInterceptor.isOperCanAccess(request, link)) {

23. //允許通路标簽body

24. return BodyTagSupport.EVAL_BODY_INCLUDE;// 傳回此則執行标簽body中内容，SKIP_BODY則不執行

25. } else {

26. return BodyTagSupport.SKIP_BODY;

27. }

29. }

31. @Override

32. public int doEndTag() throws JspException {

33. return BodyTagSupport.EVAL_BODY_INCLUDE;

34. }

36. public String getLink() {

37. return link;

38. }

40. public void setLink(String link) {

41. this.link = link;

42. }

44. }

在JSP中的使用方式：

<bgt:hasUrlPerm link="abc.do"><div>tttttttttttttttttest</div></bgt:hasUrlPerm>      

B、【控件标簽】，這種标簽直接傳回一個控件，不過是通過java代碼生成的控件内容，寫法示例：

1. package com.sdyy.common.tags;

3. import java.io.IOException;

4. import java.util.ArrayList;

5. import java.util.List;

7. import javax.servlet.jsp.JspTagException;

8. import javax.servlet.jsp.JspWriter;

9. import javax.servlet.jsp.tagext.BodyTagSupport;

13. public class ButtonUrlTag extends BodyTagSupport {

14. private static final long serialVersionUID = -7811902545513255473L;

17. //标簽屬性使用者名

18. private String user = null;

19. //标簽屬性操作url

20. private String url = null;

21. //标簽屬性 js方法

22. private String jsmethod = null;

23. //标簽屬性image 按鈕圖檔

24. private String image = null;

25. //标簽屬性 alt 提示

26. private String alt = null;

27. //标簽屬性操作value 按鈕文本

28. private String value = null;

34. public int doStartTag() throws JspTagException{

35. return super.EVAL_BODY_INCLUDE;

36. }

40. public int doEndTag() throws JspTagException{

41. pageContext.getSession();

42. Boolean b = false;

43. List list = new ArrayList();

46. try {

48. } catch (Exception e1) {

49. // TODO Auto-generated catch block

50. e1.printStackTrace();

51. }

52. for(int i = 0;i < list.size(); i++){

54. if(1==1) {//p.getUrl().trim().equals(url.trim())){

55. b = true;

56. //如果jsmethod屬性不為null 則把超連結href改為調用js

57. if(jsmethod!=null){

58. url = jsmethod;

59. }

60. }

61. }

62. JspWriter out = pageContext.getOut();

63. if(b){

64. try {

65. //有權限 顯示操作按鈕

66. out.println("<a href='" +url+ "' class='regular'><img src='" + image + "' alt='" + alt +"' />" + value + "</a>");

67. } catch (IOException e) {

68. e.printStackTrace();

69. }

70. }

72. return super.SKIP_BODY;

73. }

76. public void release(){

77. super.release();

78. }

81. public String getUser() {

82. return user;

83. }

86. public void setUser(String user) {

87. this.user = user;

88. }

91. public String getUrl() {

92. return url;

93. }

96. public void setUrl(String url) {

97. this.url = url;

98. }

101. public String getImage() {

102. return image;

103. }

106. public void setImage(String image) {

107. this.image = image;

108. }

111. public String getAlt() {

112. return alt;

113. }

116. public void setAlt(String alt) {

117. this.alt = alt;

118. }

121. public String getValue() {

122. return value;

123. }

126. public void setValue(String value) {

127. this.value = value;

128. }

130. public String getJsmethod() {

131. return jsmethod;

132. }

135. public void setJsmethod(String jsmethod) {

136. this.jsmethod = jsmethod;

137. }

138. }