为什么@PostConstruct导致我的变量在JSF中为空?

Question

在您第一次加载JSF页面时生成一个List。它是一个@PostConstruct方法。然而，它导致我的变量"Title"在我的"FilmResultBean"为空，我不明白为什么。

相关代码:

DataTableBean:

@Component
@ManagedBean(name= DataTableBean.BEAN_NAME)
@Scope("request")
public class DataTableBean implements Serializable {
public static final String BEAN_NAME = "dataTableBean";
public static Logger logger = Logger.getLogger(DataTableBean.class);

@Autowired
@ManagedProperty(value = "filmResultBean")
FilmResultBean resultBean;

@Autowired
FilmBo filmBo;
private List<FilmResultBean> filmList;
private List<String> categoryList;
private String categoryName;
private String titleInput;


/* Default Constructor */
public DataTableBean() {
}
/*Queries the Database for a list of Film Objects and returns the films in
 * a list of type "FilmResultBean"
 */

@PostConstruct
public void init(){
    filmList = filmBo.generateFilmList(resultBean);
}

public void searchByBoth(){
    filmList = filmBo.searchByBoth(resultBean);
    logger.info("FilmList Inside SEARCHBYBOTH: " + filmList);
}

public String getTitleInput() {
    return titleInput;
}
public void setTitleInput(String titleInput) {
    this.titleInput = titleInput;
}
public List<String> getCategoryList() {
    return categoryList;
}
public void setCategoryList(List<String> categoryList) {
    this.categoryList = categoryList;
}
public String getCategoryName() {
    return categoryName;
}
public void setCategoryName(String categoryName) {
    this.categoryName = categoryName;
}


public void searchFilms(){
}
public List<FilmResultBean> getFilmList() {
    return filmList;
}
public void setFilmList(List<FilmResultBean> filmList) {
    this.filmList = filmList;
}
}

JSF页面:(值是什么回来作为空，只有当我使用@PostConstruct)

<ace:textEntry value="#{filmResultBean.title}">
            <ace:ajax listener="#{dataTableBean.searchByBoth}"   execute="@this" render="form"  />
        </ace:textEntry>

特定方法被@PostConstruct调用:

@Override
public List<FilmResultBean> generateFilmList(FilmResultBean films) {
    Session session = getCurrentSession();
    List<FilmResultBean> filmList;
    Film film = new Film();
    Query query = null;
    films.setTitle(film.getTitle());
    films.setRating(film.getRating());
    films.setRentalRate(film.getRentalRate());
    String hql;
    hql = "from Film";
    query = session.createQuery(hql);
    logger.info("Query: " + query);
    filmList = (query.list());
    return filmList;
}

FilmResultBean:

@Component
@ManagedBean
@SessionScoped
@Scope("session")
public class FilmResultBean implements Serializable {
BigDecimal rentalRate;
Short length;
String rating;
String title;
String category;
public FilmResultBean() {
}
public FilmResultBean(BigDecimal rentalRate, Short length, String rating,
        String title, String category) {
    this.rentalRate = rentalRate;
    this.length = length;
    this.rating = rating;
    this.title = title;
    this.category = category;
}
public BigDecimal getRentalRate() {
    return rentalRate;
}
public void setRentalRate(BigDecimal rentalRate) {
    this.rentalRate = rentalRate;
}
public Short getLength() {
    return length;
}
public void setLength(Short length) {
    this.length = length;
}
public String getRating() {
    return rating;
}
public void setRating(String rating) {
    this.rating = rating;
}
public String getTitle() {
    return title;
}
public void setTitle(String title) {
    this.title = title;
}
public String getCategory() {
    return category;
}
public void setCategory(String category) {
    this.category = category;
}
@Override
public String toString() {
    return title;
}
}

日志信息:

23:51:41,013  INFO om.cooksys.training.dao.impl.FilmDaoImpl:  82 - Title: null
23:51:41,013  INFO om.cooksys.training.dao.impl.FilmDaoImpl:  83 - Category: null
23:51:41,038  INFO om.cooksys.training.dao.impl.FilmDaoImpl:  92 - Query:   QueryImpl(select new com.cooksys.training.FilmResultBean(fc.film.rentalRate,  fc.film.length, fc.film.rating, fc.film.title, fc.category.name) from Film f join f.filmCategories fc where f.title like :title)
Hibernate: 
select
    film2_.rental_rate as col_0_0_,
    film2_.length as col_1_0_,
    film2_.rating as col_2_0_,
    film2_.title as col_3_0_,
    category6_.name as col_4_0_ 
from
    sakila.film film0_ 
inner join
    sakila.film_category filmcatego1_ 
        on film0_.film_id=filmcatego1_.film_id,
    sakila.film film2_,
    sakila.category category6_ 
where
    filmcatego1_.film_id=film2_.film_id 
    and filmcatego1_.category_id=category6_.category_id 
    and (
        film0_.title like ?
    )
23:51:41,045  INFO       com.cooksys.training.DataTableBean:  63 - FilmList Inside     SEARCHBYBOTH: []

Answer 1

似乎您的变量(和其他像Category) 是 null，因为托管bean作为属性的注入没有正确执行，您必须通过JSF EL表达式指定其值:@ManagedProperty("#{filmResultBean}")。
我认为不建议为bean和java类混合使用Spring和JSF注释，只需保留其中一个即可。
在下面的方法中，您试图通过空电影实例设置films的属性。方法参数films在方法中被发现未使用，它的用途是什么?

@Override
public List<FilmResultBean> generateFilmList(FilmResultBean films) {
    ...
    Film film = new Film();
    ...
    films.setTitle(film.getTitle());
    films.setRating(film.getRating());
    films.setRentalRate(film.getRentalRate());
    ...
}