JSF自定义文件上传组件

最新推荐文章于 2015-09-08 21:34:20 发布

chch87

最新推荐文章于 2015-09-08 21:34:20 发布

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分类专栏： J2EE 文章标签： jsf 文件上传组件

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相信有很多使用JSF的人都和我一样比较青睐于SUN 的官方实现，但同时我们会遇到一些不方便，文件上传就是其中之一。当然我们可以选择其它实现如开源 myfaces甚至收费的实现richfaces。不过我们同样可以开发自己的组件，在这里我就以一个基于JSF1.2的文件上传组件为例介绍jsf组件开发（其中我参考了jsf1.2和myfaces1.1的源代码，开源真是好啊）。

1、准备：

先新建工程，如JSFX，并引入commons- fileupload.jar和commons-io.jar两个包（版本为1.2），源文件目录结构如下：

jsf官方实现默认是不支持multipart/form -data类型的表单的，为了使jsf能够解析multipart/form-data表单的数据，我参考了myfaces1.1的方式，然后按照commons-fileupload1.2重构了部分代码（myfaces1.1使用的是commons-fileupload1.1）

myfaces之所以能处理multipart/form-data类型的表单，关键就在于MultipartFilter和MultipartRequestWrapper这两个类，下面是我的代码：

MultipartFilter.java：

 
 package com.jsfx.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
 * 用以解析multipart表单的过滤器
 * 代码主要来自myFaces1.1的MultipartFilter类
 * 主要区别是使用了commons-fileupload1.2处理文件上传
 * */
public class MultipartFilter implements Filter {
    private int uploadMaxFileSize = 10 * 1024 * 1024; // 默认文件最大大小为10 MB 
    private int uploadThresholdSize = 1 * 1024 * 1024; // 默认临界值大小为1 MB（即超过1m的文件将使用缓存） 
    private String uploadRepositoryPath = null;//临时文件夹，默认为空，由虚拟机分配 
    public void init(FilterConfig filterConfig) {
        uploadMaxFileSize = resolveSize(filterConfig
                .getInitParameter("uploadMaxFileSize"), uploadMaxFileSize);
        uploadThresholdSize = resolveSize(filterConfig
                .getInitParameter("uploadThresholdSize"), uploadThresholdSize);
        uploadRepositoryPath = filterConfig
                .getInitParameter("uploadRepositoryPath");
    }
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        if (!(response instanceof HttpServletResponse)) {
            chain.doFilter(request, response);
            return;
        }
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        if (ServletFileUpload.isMultipartContent(httpRequest)) {//判断表单类型 
            chain.doFilter(new MultipartRequestWrapper(httpRequest,
                    uploadMaxFileSize, uploadThresholdSize,
                    uploadRepositoryPath), response);
            //如果为multipart类型，对request进行包装，使jsf能解析表单数据 
        } else {
            chain.doFilter(request, response);
        }
    }
    public void destroy() {
    }
    private int resolveSize(String param, int defaultValue) {
        int numberParam = defaultValue;
        if (param != null) {
            param = param.toLowerCase();
            int factor = 1;
            String number = param;
            if (param.endsWith("g")) {
                factor = 1024 * 1024 * 1024;
                number = param.substring(0, param.length() - 1);
            } else if (param.endsWith("m")) {
                factor = 1024 * 1024;
                number = param.substring(0, param.length() - 1);
            } else if (param.endsWith("k")) {
                factor = 1024;
                number = param.substring(0, param.length() - 1);
            }
            numberParam = Integer.parseInt(number) * factor;
        }
        return numberParam;
    }
}
 

MultipartRequestWrapper.java

 
 package com.jsfx.filter;
import java.io.File;
import java.io.UnsupportedEncodingException;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
 * Request的包装类，使jsf能解析表单数据 代码主要来自myFaces1.1的MultipartRequestWrapper类
 * 主要区别是使用了commons-fileupload1.2处理文件上传
 */
@SuppressWarnings("unchecked")
public class MultipartRequestWrapper extends HttpServletRequestWrapper {
    public static final String UPLOADED_FILES_ATTRIBUTE = "org.apache.myfaces.uploadedFiles";
    public static final String WWW_FORM_URLENCODED_TYPE = "application/x-www-form-urlencoded";
    HttpServletRequest request = null;
    HashMap parametersMap = null;// 参数表 
    ServletFileUpload fileUpload = null;
    HashMap fileItems = null;// 上传文件表 
    int maxSize;// 表单最大大小 
    int thresholdSize;// 临界值大小 
    String repositoryPath;// 临时文件夹位置 
    public MultipartRequestWrapper(HttpServletRequest request, int maxSize,
            int thresholdSize, String repositoryPath) {
        super(request);
        this.request = request;
        this.maxSize = maxSize;
        this.thresholdSize = thresholdSize;
        this.repositoryPath = repositoryPath;
    }
    @Override
    public Enumeration getParameterNames() {
        if (parametersMap == null)
            parseRequest();
        return Collections.enumeration(parametersMap.keySet());
    }
    @Override
    public String getParameter(String name) {
        if (parametersMap == null)
            parseRequest();
        String[] values = (String[]) parametersMap.get(name);
        if (values == null)
            return null;
        return values[0];
    }
    @Override
    public String[] getParameterValues(String name) {
        if (parametersMap == null)
            parseRequest();
        return (String[]) parametersMap.get(name);
    }
    @Override
    public Map getParameterMap() {
        if (parametersMap == null)
            parseRequest();
        return parametersMap;
    }
    /**
     * 获取请求中的FileItem
     */
    public FileItem getFileItem(String fieldName) {
        if (fileItems == null)
            parseRequest();
        return (FileItem) fileItems.get(fieldName);
    }
    /**
     * 获取请求中的FileItem表
     */
    public Map getFileItems() {
        if (fileItems == null)
            parseRequest();
        return fileItems;
    }
    @Override
    public Object getAttribute(String string) {
        if (string.equals(UPLOADED_FILES_ATTRIBUTE)) {
            return getFileItems();
        }
        return super.getAttribute(string);
    }
    @Override
    public String getContentType() {
        return WWW_FORM_URLENCODED_TYPE;
    }
    /**
     * 最关键的部分，解析表单数据
     */
    private void parseRequest() {
        DiskFileItemFactory factory = new DiskFileItemFactory();
        factory.setSizeThreshold(thresholdSize);// 设置临届大小 
        if (repositoryPath != null && repositoryPath.trim().length() > 0)
            factory.setRepository(new File(repositoryPath));// 设置临时文件夹 
        fileUpload = new ServletFileUpload();
        fileUpload.setFileItemFactory(factory);
        fileUpload.setSizeMax(maxSize);// 设置表单最大大小 
        String charset = request.getCharacterEncoding();
        fileUpload.setHeaderEncoding(charset);
        List requestParameters = null;
        try {
            requestParameters = fileUpload.parseRequest(request);
        } catch (FileUploadBase.SizeLimitExceededException e) {
            e.printStackTrace();
            FacesContext.getCurrentInstance().addMessage("",
                    new FacesMessage(e.getMessage()));// 文件超过大小时提示用户 
            requestParameters = Collections.EMPTY_LIST;
        } catch (FileUploadException fue) {
            fue.printStackTrace();
            FacesContext.getCurrentInstance().addMessage("",
                    new FacesMessage(fue.getMessage()));
            requestParameters = Collections.EMPTY_LIST;
        }
        parametersMap = new HashMap(requestParameters.size());// 建立参数表 
        fileItems = new HashMap();
        for (Iterator iter = requestParameters.iterator(); iter.hasNext();) {
            FileItem fileItem = (FileItem) iter.next();
            if (fileItem.isFormField()) {// 普通参数处理 
                String name = fileItem.getFieldName();
                String value = null;
                if (charset == null) {
                    value = fileItem.getString();
                } else {
                    try {
                        value = new String(fileItem.get(), charset);
                    } catch (UnsupportedEncodingException e) {
                        value = fileItem.getString();
                    }
                }
                addTextParameter(name, value);// 添加参数 
            } else {// 参数是一个文件 
                if (fileItem.getName() != null) {
                    fileItems.put(fileItem.getFieldName(), fileItem);// 添加Fileitem 
                }
            }
        }
        for (Iterator it = request.getParameterMap().entrySet().iterator(); it
                .hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();
            Object value = entry.getValue();
            if (value instanceof String[]) {
                String[] valuesArray = (String[]) entry.getValue();
                for (int i = 0; i < valuesArray.length; i++) {
                    addTextParameter((String) entry.getKey(), valuesArray[i]);
                }
            } else if (value instanceof String) {
                String strValue = (String) entry.getValue();
                addTextParameter((String) entry.getKey(), strValue);
            } else if (value != null)
                throw new IllegalStateException("value of type : "
                        + value.getClass() + " for key : " + entry.getKey()
                        + " cannot be handled.");
        }
    }
    private void addTextParameter(String name, String value) {
        if (!parametersMap.containsKey(name)) {
            String[] valuesArray = { value };
            parametersMap.put(name, valuesArray);
        } else {
            String[] storedValues = (String[]) parametersMap.get(name);
            int lengthSrc = storedValues.length;
            String[] valuesArray = new String[lengthSrc + 1];
            System.arraycopy(storedValues, 0, valuesArray, 0, lengthSrc);
            valuesArray[lengthSrc] = value;
            parametersMap.put(name, valuesArray);
        }
    }
}
 

最后在web.xml配置过滤器，sun的jsf实现就可以处理 multipart/form-data表单了。

web.xml：

 
 <?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <context-param>
        <param-name>javax.faces.CONFIG_FILES</param-name>
        <param-value>/WEB-INF/faces-config.xml</param-value>
    </context-param>
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>0</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.faces</url-pattern>
    </servlet-mapping>
    <description>=====配置过滤器=====</description>
    <filter>
        <filter-name>MultipartFilter</filter-name>
        <filter-class>com.jsfx.filter.MultipartFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>MultipartFilter</filter-name>
        <servlet-name>Faces Servlet</servlet-name>
    </filter-mapping>
    <description>==================</description>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>
 

2、UploadedFile.java：作为标签的value存储上传文件相关属性的类。

 
 package com.jsfx.fileupload;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.fileupload.FileItem;
public class UploadedFile {
    private String name;
    private String contentType;
    private FileItem fileItem;
    public UploadedFile(FileItem fileItem) throws IOException {
        this.name = fileItem.getName();
        this.contentType = fileItem.getContentType();
        this.fileItem = fileItem;
    }
    public void save(String file) {// 保存文件 
        try {
            fileItem.write(new File(file));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public byte[] getBytes() throws IOException {
        byte[] bytes = new byte[(int) getSize()];
        if (fileItem != null)
            fileItem.getInputStream().read(bytes);
        return bytes;
    }
    public InputStream getInputStream() throws IOException {
        return fileItem != null ? fileItem.getInputStream()
                : new ByteArrayInputStream(new byte[0]);
    }
    public String getContentType() {
        return contentType;
    }
    public String getName() {
        return name;
    }
    public long getSize() {
        return fileItem != null ? fileItem.getSize() : 0;
    }
}
 

UploadedFileConverter.java用来转化UploadedFile的类型

 
 package com.jsfx.fileupload;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.ConverterException;
public class UploadedFileConverter implements Converter {
    public Object getAsObject(FacesContext facescontext,
            UIComponent uicomponent, String s) throws ConverterException {
        return null;
    }
    public String getAsString(FacesContext facescontext,
            UIComponent uicomponent, Object obj) throws ConverterException {
        if (obj instanceof UploadedFile) {
            return ((UploadedFile) obj).getName();
        } else {
            return null;
        }
    }
}
 

3、实现标签描述库，这里使用的UploadTag类，下面将会提到

jsfx.tld（注意看它在上面项目中的位置）

 
 <?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.1" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee web-jsptaglibrary_2_1.xsd">
    <tlib-version>1.0</tlib-version>
    <short-name>x</short-name>
    <uri>http://jsfx.com/</uri>
    <tag>
        <name>upload</name>
        <tag-class>com.jsfx.fileupload.UploadTag</tag-class>
        <body-content>JSP</body-content>
        <description>
            为了简化开发只定义了几个必要和常用的属性如id，value，required，style，onchange等等
        </description>
        <attribute>
            <name>id</name>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
        <attribute>
            <name>value</name>
            <rtexprvalue>false</rtexprvalue>
            <deferred-value>
                <type>com.jsfx.fileupload.UploadedFile</type>
            </deferred-value>
        </attribute>
        <attribute>
            <name>converter</name>
            <rtexprvalue>false</rtexprvalue>
            <deferred-value>
                <type>com.jsfx.fileupload.UploadedFileConvert</type>
            </deferred-value>
        </attribute>
        <attribute>
            <name>required</name>
            <rtexprvalue>false</rtexprvalue>
            <deferred-value>
                <type>boolean</type>
            </deferred-value>
        </attribute>
        <attribute>
            <name>disabled</name>
            <rtexprvalue>false</rtexprvalue>
            <deferred-value>
                <type>boolean</type>
            </deferred-value>
        </attribute>
        <attribute>
            <name>readonly</name>
            <rtexprvalue>false</rtexprvalue>
            <deferred-value>
                <type>boolean</type>
            </deferred-value>
        </attribute>
        <attribute>
            <name>style</name>
            <rtexprvalue>false</rtexprvalue>
            <deferred-value>
                <type>java.lang.String</type>
            </deferred-value>
        </attribute>
        <attribute>
            <name>styleClass</name>
            <rtexprvalue>false</rtexprvalue>
            <deferred-value>
                <type>java.lang.String</type>
            </deferred-value>
        </attribute>
        <attribute>
            <name>onchange</name>
            <required>false</required>
            <deferred-value>
                <type>java.lang.String</type>
            </deferred-value>
        </attribute>
    </tag>
</taglib>
 

一个jsf自定义组件通常由

（1）标签属性处理类：主要作用是从页面标签接收值。继承至UIComponentELTag，这里与jsf1.1不同，由于使用了统一EL表达式。

（2）Component类：主要作用为在Server端保存及恢复组件状态。

（3）Renderer类：主要功能是在响应阶段将Java组件的属性转换为HTML代码，在接受请求阶段将HTML Request中传来的资料转换为Java组件的属性。

4、标签属性处理类：

UploadTag.java

 
 package com.jsfx.fileupload;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.webapp.UIComponentELTag;
import javax.servlet.jsp.JspException;
public class UploadTag extends UIComponentELTag {
    private javax.el.ValueExpression value;
    private javax.el.ValueExpression converter;
    private javax.el.ValueExpression styleClass;
    private javax.el.ValueExpression disabled;
    private javax.el.ValueExpression required;
    private javax.el.ValueExpression style;
    private javax.el.ValueExpression onchange;
    @Override
    public String getComponentType() {
        return "HtmlUpload";//返回Component的类型，在faces-config.xml中找到相应的类 
    }
    @Override
    public String getRendererType() {
        return "UploadRenderer";//返回Renderer的类型，在faces-config.xml中找到相应的类 
    }
    public void setValue(javax.el.ValueExpression value) {
        this.value = value;
    }
    public void setConverter(javax.el.ValueExpression converter) {
        this.converter = converter;
    }
    public void setRequired(javax.el.ValueExpression required) {
        this.required = required;
    }
    public void setDisabled(javax.el.ValueExpression disabled) {
        this.disabled = disabled;
    }
    public void setStyle(javax.el.ValueExpression style) {
        this.style = style;
    }
    public void setStyleClass(javax.el.ValueExpression styleClass) {
        this.styleClass = styleClass;
    }
    public void setOnchange(javax.el.ValueExpression onchange) {
        this.onchange = onchange;
    }
    @Override
    protected void setProperties(UIComponent component) {
        super.setProperties(component);
        javax.faces.component.UIInput input = null;
        try {
            input = (javax.faces.component.UIInput) component;
        } catch (ClassCastException cce) {
            throw new IllegalStateException(
                    "Component "
                            + component.toString()
                            + " not expected type.  Expected: javax.faces.component.UIInput.  Perhaps you're missing a tag?");
        }
        if (converter != null) {
            if (!converter.isLiteralText()) {
                input.setValueExpression("converter", converter);
            } else {
                Converter conv = FacesContext.getCurrentInstance()
                        .getApplication().createConverter(
                                converter.getExpressionString());
                input.setConverter(conv);
            }
        }
        if (value != null) {
            input.setValueExpression("value", value);
        }
        if (required != null) {
            input.setValueExpression("required", required);
        }
        if (disabled != null) {
            input.setValueExpression("disabled", disabled);
        }
        if (style != null) {
            input.setValueExpression("style", style);
        }
        if (styleClass != null) {
            input.setValueExpression("styleClass", styleClass);
        }
        if (onchange != null) {
            input.setValueExpression("onchange", onchange);
        }
    }
    @Override
    public int doStartTag() throws JspException {
        try {
            return super.doStartTag();
        } catch (Exception e) {
            Throwable root = e;
            while (root.getCause() != null) {
                root = root.getCause();
            }
            throw new JspException(root);
        }
    }
    @Override
    public int doEndTag() throws JspException {
        try {
            return super.doEndTag();
        } catch (Exception e) {
            Throwable root = e;
            while (root.getCause() != null) {
                root = root.getCause();
            }
            throw new JspException(root);
        }
    }
    @Override
    public void release() {
        super.release();
        this.value = null;
        this.converter = null;
        this.disabled = null;
        this.style = null;
        this.styleClass = null;
        this.required = null;
        this.onchange = null;
    }
}
 

5、Component类

HtmlUpload.java

 
 package com.jsfx.fileupload;
import java.util.ArrayList;
import java.util.List;
import javax.el.ValueExpression;
import javax.faces.component.UIInput;
public class HtmlUpload extends UIInput {
    private java.lang.Boolean disabled;
    private java.lang.String style;
    private java.lang.String styleClass;
    private java.lang.String onchange;
    public java.lang.String getOnchange() {
        if (null != this.onchange) {
            return this.onchange;
        }
        ValueExpression _ve = getValueExpression("onchange");
        if (_ve != null) {
            return (java.lang.String) _ve.getValue(getFacesContext()
                    .getELContext());
        } else {
            return null;
        }
    }
    public void setOnchange(java.lang.String onchange) {
        this.onchange = onchange;
        handleAttribute("onchange", onchange);
    }
    public boolean isDisabled() {
        if (null != this.disabled) {
            return this.disabled;
        }
        ValueExpression _ve = getValueExpression("disabled");
        if (_ve != null) {
            return (java.lang.Boolean) _ve.getValue(getFacesContext()
                    .getELContext());
        } else {
            return false;
        }
    }
    public void setDisabled(boolean disabled) {
        this.disabled = disabled;
    }
    public java.lang.String getStyle() {
        if (null != this.style) {
            return this.style;
        }
        ValueExpression _ve = getValueExpression("style");
        if (_ve != null) {
            return (java.lang.String) _ve.getValue(getFacesContext()
                    .getELContext());
        } else {
            return null;
        }
    }
    public void setStyle(java.lang.String style) {
        this.style = style;
        handleAttribute("style", style);
    }
    public java.lang.String getStyleClass() {
        if (null != this.styleClass) {
            return this.styleClass;
        }
        ValueExpression _ve = getValueExpression("styleClass");
        if (_ve != null) {
            return (java.lang.String) _ve.getValue(getFacesContext()
                    .getELContext());
        } else {
            return null;
        }
    }
    public void setStyleClass(java.lang.String styleClass) {
        this.styleClass = styleClass;
    }
    public HtmlUpload() {
        super();
        setRendererType("TestRenderer");
    }
    @SuppressWarnings("unchecked")
    private void handleAttribute(String name, Object value) {
        List<String> setAttributes = null;
        setAttributes = (List<String>) this.getAttributes().get(
                "javax.faces.component.UIComponentBase.attributesThatAreSet");
        if (setAttributes == null) {
            setAttributes = new ArrayList<String>(6);
            this
                    .getAttributes()
                    .put(
                            "javax.faces.component.UIComponentBase.attributesThatAreSet",
                            setAttributes);
        }
        if (value == null) {
            setAttributes.remove(name);
        } else if (!setAttributes.contains(name)) {
            setAttributes.add(name);
        }
    }
}
 

6、Renderer类

UploadRenderer.java

 
 package com.jsfx.fileupload;
import java.io.IOException;
import java.util.Map;
import javax.faces.component.UIComponent;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.convert.ConverterException;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import org.apache.commons.fileupload.FileItem;
import com.jsfx.filter.MultipartRequestWrapper;
import com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer;
public class UploadRenderer extends HtmlBasicInputRenderer {
    
    @Override
    /**
     * 生成<input: type=file/>的html标签
     * */
    protected void getEndTextToRender(FacesContext context,
            UIComponent component, String currentValue) throws IOException {
        String style = (String) component.getAttributes().get("style");
        String styleClass = (String) component.getAttributes()
                .get("styleClass");
        Boolean disabled = (Boolean) component.getAttributes().get("disabled");
        String onchange = (String) component.getAttributes().get("onchange");
        ResponseWriter writer = context.getResponseWriter();
        assert (writer != null);
        writer.startElement("input", component);
        writeIdAttributeIfNecessary(context, writer, component);
        writer.writeAttribute("type", "file", null);
        writer.writeAttribute("name", (component.getClientId(context)),
                "clientId");
        if (currentValue != null) {
            writer.writeAttribute("value", currentValue, "value");
        }
        if (null != styleClass) {
            writer.writeAttribute("class", styleClass, "styleClass");
        }
        if (null != style) {
            writer.writeAttribute("style", style, "style");
        }
        if (null != disabled) {
            writer.writeAttribute("disabled", disabled, "disabled");
        }
        if (null != onchange) {
            writer.writeAttribute("onchange", onchange, "onchange");
        }
        writer.endElement("input");
    }
    @Override
    @SuppressWarnings("unchecked")
    /**
     * 这个方法将取出Request中的文件数据，并将提交的“value” uploadedFile实例化
     * */
    public void decode(FacesContext facesContext, UIComponent uiComponent) {
        super.decode(facesContext, uiComponent);
        Object request = facesContext.getExternalContext().getRequest();
        if (!(request instanceof ServletRequest)) {
            ExternalContext externalContext = facesContext.getExternalContext();
            Map fileItems = (Map) externalContext.getRequestMap().get(
                    MultipartRequestWrapper.UPLOADED_FILES_ATTRIBUTE);
            FileItem fileItem = null;
            if (fileItems != null) {
                String paramName = uiComponent.getClientId(facesContext);
                fileItem = (FileItem) fileItems.get(paramName);
            }
            if (fileItem != null) {
                try {
                    UploadedFile upFile;
                    upFile = new UploadedFile(fileItem);//实例化提交的value 
                    ((HtmlUpload) uiComponent).setSubmittedValue(upFile);
                    ((HtmlUpload) uiComponent).setValid(true);
                } catch (IOException ioe) {
                    ioe.printStackTrace();
                }
            }
            return;
        }
        if (facesContext.getExternalContext().getRequest() instanceof ServletRequest) {
            ServletRequest multipartRequest = (ServletRequest) facesContext
                    .getExternalContext().getRequest();
            while (multipartRequest != null
                    && !(multipartRequest instanceof MultipartRequestWrapper)) {
                if (multipartRequest instanceof HttpServletRequestWrapper) {
                    multipartRequest = ((HttpServletRequestWrapper) multipartRequest)
                            .getRequest();
                } else {
                    multipartRequest = null;
                }
            }
            if (multipartRequest != null) {
                MultipartRequestWrapper mpReq = (MultipartRequestWrapper) multipartRequest;
                String paramName = uiComponent.getClientId(facesContext);
                FileItem fileItem = mpReq.getFileItem(paramName);
                if (fileItem != null) {
                    try {
                        UploadedFile upFile;
                        upFile = new UploadedFile(fileItem);//实例化提交的value 
                        ((HtmlUpload) uiComponent).setSubmittedValue(upFile);
                        ((HtmlUpload) uiComponent).setValid(true);
                    } catch (IOException ioe) {
                        ioe.printStackTrace();
                    }
                }
            }
        }
    }
    @Override
    public Object getConvertedValue(FacesContext context,
            UIComponent component, Object submittedValue)
            throws ConverterException {
        if (submittedValue instanceof UploadedFile) {
            UploadedFile file = (UploadedFile) submittedValue;
            if (file.getName() != null && file.getName().length() > 0) {
                return file;
            }
        }
        return null;
    }
}
 

7、整合

上面几个部分需要配置才能互相配合工作，这就需要UploadTag.java中的 getComponentType()、getRendererType()两个方法及配置文件。为了保证组件的独立性，我把faces-config.xml打包进了类的META-INF文件夹（见最上面项目的结构）。

faces-config.xml：

 
 <?xml version="1.0" encoding="UTF-8"?>
<faces-config version="1.2" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xi="http://www.w3.org/2001/XInclude"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_1_2.xsd">
    <component>
        <component-type>HtmlUpload</component-type>
        <component-class>
            com.jsfx.fileupload.HtmlUpload
        </component-class>
    </component>
    <render-kit>
        <renderer>
            <component-family>javax.faces.Input</component-family>
            <renderer-type>UploadRenderer</renderer-type>
            <renderer-class>
                com.jsfx.fileupload.UploadRenderer
            </renderer-class>
        </renderer>
    </render-kit>
</faces-config>
 