Question

我将我的知识转移到春天，我真的不知道这是如何工作的。我试图做一个非常基本的例子来使它工作，但我无法使它工作： - （（

的applicationContext.xml

<bean id="serviceTest" class="es.mov.jose.agenda.ServiceTest">
</bean>

    <bean id="serviceMovility" class="es.mov.jose.agenda.ServiceMovility">
    <property name="serviceTest" ref="serviceTest" />
</bean>

    <bean name="/jose/req1.do" class="org.springframework.web.servlet.mvc.ParameterizableViewController">
    <property name="viewName" value="jose/req1" />
</bean>

ServiceMovility.java

package es.mov.jose.agenda;

public interface ServiceMovility {
        public String callTest();
}

ServiceMovilityImpl.java

package es.mov.jose.agenda;

import es.mov.jose.agenda.ServiceMovility;

public class ServiceMovilityImpl implements ServiceMovility {

    private ServiceTest serviceTest;    
    public String callTest() {
        return serviceTest.getValue();
    }

}

ServiceTest.java

package es.mov.jose.agenda;

public interface ServiceTest {
        public String getValue();
}

ServiceTestImpl.java

package es.mov.jose.agenda;

import es.mov.jose.agenda.ServiceTest;

public class ServiceTestImpl implements ServiceTest {

    public String getValue() {
        return "OK";
    }

}

最后是我的req1.jsp

<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<%@ page import="es.mov.jose.agenda.ServiceMovility"%>
<%@ page import="es.mov.jose.agenda.ServiceMovilityImpl"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib uri = "http://java.sun.com/jsp/jstl/functions" prefix="fn"%>
<%@ taglib prefix="sp-forms" uri="http://www.springframework.org/tags/form"%>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">    
</head>
<body>
<jsp:useBean id="serviceMovility" scope="request"     class="es.mov.jose.agenda.ServiceMovilityImpl" />
<div class="main" >
    <%
    String result = serviceMovility.callTest();
    out.println(result);
    %>
</div>
</body>
</html>

它完美地调用了serviceMovility但是在callTest方法中调用serviceTest失败了，它说java.lang.NullPointerException ¿我应该在jsp文件中以这种方式包含bean serviceMovility吗？ ¿为什么spring不会在serviceMovility上注入serviceTest？

我花了两天时间，但我的所有解决方案都失败了。我不知道该怎么做。

提前致谢。

Answer 1

在定义bean时使用实现而不是接口：

<bean id="serviceTest" class="es.mov.jose.agenda.ServiceTestImpl" />

<bean id="serviceMovility" class="es.mov.jose.agenda.ServiceMovilityImpl">
  <property name="serviceTest" ref="serviceTest" />
</bean>

<bean name="/jose/req1.do"
    class="es.mov.jose.agenda.Req1Controller">
  <property name="viewName" value="jose/req1" />
  <property name="serviceMovility" ref="serviceMovility" />
</bean>

plus，在你的* Impl类中定义了注入依赖项的setter，即在ServiceMovilityImpl：

public void setServiceTest(ServiceTest serviceTest) {
  this.serviceTest = serviceTest;
}

修改：

你做错了......不要将bean注入JSP（通过jsp:useBean），而是直接注入Controller。定义自己的控制器：

package es.mov.jose.agenda; final class Req1Controller extends ParameterizableViewController { private ServiceMovility serviceMovility; @Override protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception { ModelAndView mav = new ModelAndView(getViewName()); mav.addObject("callTest", serviceMovility.callTest()); return mav; } public void setServiceMovility(ServiceMovility serviceMovility) { this.serviceMovility = serviceMovility; } }

像我上面那样编辑你的ApplicationContext.xml（使用Req1Controller代替ParameterizableViewController），在JSP中你将拥有${callTest}变量：

<body> <div class="main" > <c:out value="${callTest}" /> </div> </body>

Answer 2

少数事情：

你不能创建界面实例：

<bean id="serviceMovility" class="es.mov.jose.agenda.ServiceMovility">
it shout be
<bean id="serviceMovility" class="es.mov.jose.agenda.ServiceMovilityImpl">

ServiceMovilityImpl必须为字段定义set方法。要做到这一点：

<property name="serviceTest" ref="serviceTest" />

这样做：

package es.mov.jose.agenda;

import es.mov.jose.agenda.ServiceMovility;

public class ServiceMovilityImpl implements ServiceMovility {

    private ServiceTest serviceTest;    

    public void setServiceTest(ServiceTest serviceTest){
        this.serviceTest = serviceTest;
    }

    public String callTest() {
        return serviceTest.getValue();
    }

}

Spring新手，在jsp页面中调用spring bean方法（2.5，xml），进行测试

2 个答案: