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java中反射，枚举实际应用例子
时间：2015-06-18 编辑：简简单单 来源：一聚教程网
遇到的问题
一个List
列表中有枚举类型
枚举类型在页面显示的 时候就不能通过。属性来取数据
用反射
根据名字去匹配对应的类名 从而获取对应的属性值（反射）
jsp页面
<%@taglib uri="/WEB-INF/tld/MethodUtil.tld" prefix="methodUtil"%>
tld
PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
"http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
This Tag Library makes user develope JSP with method Value component easily.
className
method
paramType
param
反射帮助类
import java.io.IOException;
import java.lang.reflect.Method;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;
@SuppressWarnings("unused")
public class MethodUtilTag extends SimpleTagSupport {
private String className;
private String method;
private String paramType;
private String param;
private String path;
@Override
@SuppressWarnings("unchecked")
public void doTag() throws JspException, IOException {
JspWriter out = getJspContext().getOut();
Class[] parasClass = null;
Object[] args = null;
if(StringUtil.isNotEmpty(param)) {
if(param.contains(",")) {
String[] params = StringUtil.split(param, ",", false);
parasClass = new Class[params.length];
args = new Object[params.length];
for (int i = 0; i < parasClass.length; i++) {
parasClass[i] = String.class;
args[i] = params[i];
}
}
}
Class classType = String.class;
String value = "";
if("int".equals(paramType) || "Integer".equals(paramType)) {
classType = Integer.class;
} else if("double".equals(paramType) || "Double".equals(paramType)) {
classType = Double.class;
}
if(StringUtil.isNotEmpty(className) && StringUtil.isNotEmpty(method)) {
try {
String packagePath = this.className;
if(StringUtil.isNotEmpty(path)) {
packagePath = this.path + "." + packagePath;
} else {
packagePath = "这里是类的包名字." + packagePath;
}
Class clazz = Class.forName(packagePath);
Object newInstance = clazz.newInstance();
Method m = null;
Object object = null;
if(parasClass != null) {
m = clazz.getMethod(method, parasClass);
object = m.invoke(newInstance, args);
} else {
m = clazz.getMethod(method, classType);
object = m.invoke(newInstance, new Object[]{param});
}
value = object.toString();
} catch (Exception e) {
value = "";
e.printStackTrace();
}
}
out.print(value);
}
public String getClassName() {
return className;
}
public void setClassName(String className) {
this.className = className;
}
public String getMethod() {
return method;
}
public void setMethod(String method) {
this.method = method;
}
public String getParam() {
return param;
}
public void setParam(String param) {
this.param = param;
}
public String getParamType() {
return paramType;
}
public void setParamType(String paramType) {
this.paramType = paramType;
}
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
}
反射转换实体类
public class xxxUtil {
public String convert(String value){
if ("yq1012".equals(value)) {
return 枚举.getName();//枚举的要导入对应的包名字
} else {
return null;
}
}
}
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