自定义标签：在JSP页面中动态执行Spring Bean的方法
使用该自定义标签，可以在JSP页面中动态执行某个Spring Bean对象的一个方法，方法返回的结果存储在ValueStack中。该自定义标签在Spring2、Struts2、Hibernate3环境下测试通过。一、java源代码
1、ServiceTag源代码
public class ServiceTag extends BaseBodyTagSupport {private String beanName;private String methodName;private String id;public List params = new ArrayList();public void setBeanName(String beanName) {this.beanName = beanName;}public void setMethodName(String methodName) {this.methodName = methodName;}public void setId(String id) {this.id = id;}public int doEndTag() throws JspException {Object bean = null;Method method = null;//取得bean对象try{bean = SpringContextUtil.getBean(beanName);}catch(Exception ex){throw new JspException("get bean error: " + beanName);}//通过反射取得方法if(bean != null){try {method = bean.getClass().getMethod(methodName, TagUtil.getParameterTypes(params));}catch(Exception e) {throw new JspException("get method error: " + beanName + "." + methodName);}}else{throw new JspException("ServiceTag Error: bean [" + beanName + "] is null");}//通过反射执行方法，得到结果Object result = null;if(method != null){try {result = method.invoke(bean, TagUtil.getParameterValues(params));}catch(Exception e){throw new JspException("method invoke error");}}//将结果存储在ValueStack中ValueStack vs = TagUtils.getStack(pageContext);vs.getContext().put(id, result);return EVAL_PAGE;}}
2、ServiceParamTag源代码
public class ServiceParamTag extends BaseBodyTagSupport {private String name;private Object value;private String type;public void setName(String name) {this.name = name;}public void setValue(Object value) {this.value = value;}public void setType(String type) {this.type = type;}public int doEndTag() throws JspException {Tag parent = getParent();if(parent instanceof ServiceTag){Map p = new HashMap();p.put("paramName", name);p.put("paramValue", value);p.put("paramType", type);((ServiceTag)parent).params.add(p);}return EVAL_PAGE;}}
3、公共方法源代码
//参数类型数组public static Class[] getParameterTypes(List params) throws Exception{Class[] c = new Class;for(int i=0;i<params.size();i++){Map p = (Map)params.get(i);String type = (String)p.get("paramType");c = Class.forName(type);}return c;}//参数值数组public static Object[] getParameterValues(List params) throws Exception{Object[] o = new Object;for(int i=0;i<params.size();i++){Map p = (Map)params.get(i);o = p.get("paramValue");}return o;}
二、tld文件源代码
<tag><name>serviceBean</name><tag-class>com.cjm.web.taglib.ServiceTag</tag-class><body-content>JSP</body-content><attribute><name>beanName</name><required>true</required><rtexprvalue>true</rtexprvalue></attribute><attribute><name>methodName</name><required>true</required><rtexprvalue>true</rtexprvalue></attribute><attribute><name>id</name><required>true</required><rtexprvalue>true</rtexprvalue></attribute></tag><tag><name>serviceParam</name><tag-class>com.cjm.web.taglib.ServiceParamTag</tag-class><body-content>JSP</body-content><attribute><name>name</name><required>true</required><rtexprvalue>true</rtexprvalue></attribute><attribute><name>value</name><required>true</required><rtexprvalue>true</rtexprvalue></attribute><attribute><name>type</name><required>true</required><rtexprvalue>true</rtexprvalue></attribute></tag>
三、范例
1、java源代码
public class RoleService extends BaseService {private RoleDao roleDao;public RoleDao getRoleDao() {return roleDao;}public void setRoleDao(RoleDao roleDao) {this.roleDao = roleDao;}public Role getRole(String roleId){return (Role)get(Role.class, roleId);}} 2、JSP页面源代码
<cjm:serviceBean beanName="roleService" methodName="getRole" id="result"><cjm:serviceParam name="roleId" value="ADMIN" type="java.lang.String"/></cjm:serviceBean><s:property value="#result.roleName"/>
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