Question

美好的一天。在我的项目中，我有一个自定义对象列表，我在PrimeFaces p:selectCheckboxMenu中使用它。我在这门课上使用转换器。下拉列表看起来很棒，如果我从列表中选择一个项目，那么＆＃34;筹码＆＃34;正确显示。但是，如果我在初始化时加载所选列表，则选择＆＃34;芯片＆＃34;显示类引用（com.test.Characteristic@56e76bff）而不是对象的值。我希望它能从转换器中显示getAsString的返回值。我究竟做错了什么？

转到此代码： 自定义对象

    public class Characteristic {
    public Characteristic() {
        super();
    }
    private String key;
    private String value;
    private String type;

    public Characteristic(String key, String value, String type) {
        this.key = key;
        this.value = value;
        this.type = type;
    }

    public void setKey(String key) {
        this.key = key;
    }

    public String getKey() {
        return key;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String getValue() {
        return value;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getType() {
        return type;
    }
}

转化器：

    @FacesConverter(value = "characteristicConverter")
    public class CharacteristicConverter implements Converter {
        public Object getAsObject(FacesContext fc, UIComponent uic, String value) {
            return new Characteristic("testKey", value, "testType");
        }

        public String getAsString(FacesContext fc, UIComponent uic, Object object) {
            if (object == null) {
                return "";
            }
            if (object instanceof Characteristic) {
                Characteristic cha = (Characteristic) object;
                String name = cha.getValue();
                System.out.println("In the converter. Returning " + name);                
                return name;
            } else {
                throw new ConverterException(new FacesMessage(object + " is not a Characteristic"));
            }
        }
    }

转换器中的System.out.prinln在运行时会显示：

在转换器中。返回char1value

在转换器中。返回char2value

在转换器中。返回char3value

在转换器中。返回char1value

The Bean：

@ManagedBean(name = "checkboxView")
public class CheckboxView {

    private List<Characteristic> allChars;
    private List<Characteristic> selectedChars;

    @PostConstruct
    public void init() {

        allChars = new ArrayList<Characteristic>();
        allChars.add(new Characteristic("char1key","char1value","test"));
        allChars.add(new Characteristic("char2key","char2value","test"));
        allChars.add(new Characteristic("char3key","char3value","test"));
        selectedChars = new ArrayList<Characteristic>();
        selectedChars.add(new Characteristic("char1key","char1value","test"));
    }

    public void setAllChars(List<Characteristic> allChars) {
        this.allChars = allChars;
    }

    public List<Characteristic> getAllChars() {
        return allChars;
    }

    public void setSelectedChars(List<Characteristic> selectedChars) {
        this.selectedChars = selectedChars;
    }

    public List<Characteristic> getSelectedChars() {
        return selectedChars;
    }
}

页面：

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core"
      xmlns:p="http://primefaces.org/ui">
    <h:head></h:head>
    <h:body>
        <h:form>
            <p:selectCheckboxMenu id="multiple" value="#{checkboxView.selectedChars}" label="Characteristics"
                                  multiple="true" filter="true" filterMatchMode="startsWith"
                                  converter="characteristicConverter">
                <f:selectItems value="#{checkboxView.allChars}" var="cha" itemLabel="#{cha.value}" itemValue="#{cha}"/>
            </p:selectCheckboxMenu>
        </h:form>
    </h:body>
</html>

Answer 1

我怀疑它与将列表中的特征与预先选择的特征进行比较有关（因为在视觉列表中它也没有被选中，并且很可能也会因h:selectManyCheckbox而失败）。您可以尝试更改

@PostConstruct
public void init() {

    allChars = new ArrayList<Characteristic>();
    allChars.add(new Characteristic("char1key","char1value","test"));
    allChars.add(new Characteristic("char2key","char2value","test"));
    allChars.add(new Characteristic("char3key","char3value","test"));
    selectedChars = new ArrayList<Characteristic>();
    selectedChars.add(new Characteristic("char1key","char1value","test"));
}

到

@PostConstruct
public void init() {

    allChars = new ArrayList<Characteristic>();
    Characteristic char1 = new Characteristic("char1key","char1value","test");
    Characteristic char2 = new Characteristic("char2key","char2value","test");
    Characteristic char3 = new Characteristic("char3key","char3value","test");
    allChars.add(char1);
    allChars.add(char2);
    allChars.add(char3);


    selectedChars = new ArrayList<Characteristic>();
    selectedChars.add(char1);
}

因此，所选的'char1'与列表中的对象明确相同。但更好的方法是尝试明确地实现特征的等于和散列。

最初在p：selectCheckboxMenu中选择的项目显示对象引用而不是值

1 个答案: