Question

我已经创建了一个自定义组件，根据bean向页面显示一些数据。问题是我无法将bean绑定到我的组件。我在ValueExpresion课程中使用UIComponentELTag。我收到此错误：

org.apache.jasper.JasperException：PWC6338：无法转换“＃{helloBean.color}”作为bean的属性颜色javax.el.ValueExpression：PWC6348：属性编辑器未向PropertyEditorManager注册

index.jsp

<d:hello name="Something"
    color="#{helloBean.color}" 
    welcome="#{helloBean.welcome}">
</d:hello>

hello.tld

<tag>
    <name>hello</name>
    <tag-class>custom.HelloTag</tag-class>
    <body-content>JSP</body-content>
    <attribute>
        <name>name</name>
        <type>java.lang.String</type>
    </attribute>
    <attribute>
        <name>color</name>
        <type>java.lang.String</type>
    </attribute>
</tag>

HelloTag.java`

public class HelloTag extends UIComponentELTag {
    ValueExpression color;
    ValueExpression welcome;
    String name;

    public ValueExpression getColor() {
        return color;
    }

    public void setColor(ValueExpression color) {
        this.color = color;
    }
    @Override
    protected void setProperties(UIComponent component) {System.out.println("IN");
        super.setProperties(component);
        UIHello componentCst = (UIHello) component;
        if (color.isLiteralText()) {
        componentCst.setValueExpression("color", color);
        } else {
        component.getAttributes().put("color", color.getExpressionString());
    }

        componentCst.getAttributes().put("color", "color:" + getColor() + ";");
        componentCst.getAttributes().put("name", getName());
    }
}

UIHello.java - extends UIOutput

public class UIHello extends UIOutput {
    ...
}

faces-config.xml

<faces-config
    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-facesconfig_1_2.xsd"
    version="1.2">
    <component>
        <component-type>hello</component-type>
        <component-class>custom.UIHello</component-class>
    </component>
    <managed-bean>
        <managed-bean-name>helloBean</managed-bean-name>
        <managed-bean-class>dto.HelloBeanDTO</managed-bean-class>
        <managed-bean-scope>session</managed-bean-scope>
    <managed-property>
        <property-name>color</property-name>
        <property-class>java.lang.String</property-class>
        <value>green</value>
    </managed-property>
    <managed-property>
        <property-name>welcome</property-name>
        <property-class>java.lang.String</property-class>
        <value>Bine ai venit</value>
    </managed-property>
    </managed-bean>

    <render-kit>
        <display-name>Hello Render</display-name>
    <renderer>
        <display-name>Hello Render</display-name>
        <component-family>hello</component-family>
        <renderer-type>hello</renderer-type>
        <renderer-class>custom.HelloRender</renderer-class>
        </renderer>
    </render-kit>
</faces-config>

Answer 1

您忘记<type> color <deferred-value> hello.tld <tag> <name>hello</name> <tag-class>custom.HelloTag</tag-class> <body-content>JSP</body-content> <attribute> <name>name</name> <type>java.lang.String</type> </attribute> <attribute> <name>color</name> <deferred-value> <type>java.lang.String</type> </deferred-value> </attribute> </tag> <deferred-value>。{/}

welcome

使用{{1}}，您基本上指定该属性接受延迟值表达式，并且应该将其视为而不是普通的香草字符串。

请注意，您的{{1}}属性已丢失。您可能也想添加它。

另见：

Java EE 5 tutorial - Creating custom components - Defining the TLD

无法将“＃{bean.color}”转换为bean javax.el.ValueExpression的属性颜色

1 个答案:

另见：