Any scoped managed bean method annotated with @PostConstruct will be called
after the managed bean is instantiated,but before the bean is placed in scope.

考虑

<h:inputText binding="#{bean.input}" >
</h:inputText>

托管bean的位置

public class Bean {
    private HtmlInputText input; 
    public PreInitializeBean(){
        input = new HtmlInputText();
        input.setMaxlength(15);
        input.setStyle("background: pink;");
        input.setValue(fetchValueFromDatabase());
    }

    private Object fetchValueFromDatabase() {
        String resultValue = null;
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            Connection con = DriverManager.getConnection(
                    "jdbc:oracle:thin:@localhost:1521:xe","system","system");


            System.out.println("Connection Object: "+con);
            // retieving data from RESULT table
            PreparedStatement ps = con
                    .prepareStatement("select * from RESULT",ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);

            ResultSet rs = ps.executeQuery();
            while (rs.next()) {
                System.out.print("<br>" + rs.getInt(1) + " " + rs.getString(2) + " "
                        + rs.getString(3) + " " + rs.getString(4));
                resultValue = rs.getString(2);
            }

            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return resultValue;
    }

    public HtmlInputText getInput() {
        return input;
    }

    public void setInput(HtmlInputText input) {
        this.input = input;
    }

}

当我在Contructor中执行初始化时,我在inputtext字段中什么也得不到,但是我得到了预期的(inputtext框中的值),如果我正在做什么,我将它放在标有@PostContruct的方法中.
将构造函数方法替换为：

@PostConstruct
    public void init() {
        input = new HtmlInputText();
        input.setMaxlength(15);
        input.setStyle("background: pink;");
        input.setValue(fetchValueFromDatabase());
    }

@Luiggi似乎在回应我的评论时提供了一些帮助here.

注意：这也可以.

private String input;

public Bean(){
    this.input= fetchValueFromDatabase();
}