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XML 配置

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">

    <util:properties id="mongoProperties" location="file:///storage/local.properties" />

    <bean id="mongoService" class="com.business.persist.MongoService"></bean>
</beans>

MongoService 看起来像 

@Service
public class MongoService {

    @Value("#{mongoProperties[host]}")
    private String host;

    @Value("#{mongoProperties[port]}")
    private int port;

    @Value("#{mongoProperties[database]}")
    private String database;

    private Mongo mongo;

    private static final Logger LOGGER = LoggerFactory.getLogger(MongoService.class);

    public MongoService() throws UnknownHostException {
        LOGGER.info("host=" + host + ", port=" + port + ", database=" + database);
        mongo = new Mongo(host, port);
    }

    public void putDocument(@Nonnull final DBObject document) {
        LOGGER.info("inserting document - " + document.toString());
        mongo.getDB(database).getCollection(getCollectionName(document)).insert(document, WriteConcern.SAFE);
    }

我把我的 MongoServiceTest 写成

public class MongoServiceTest {

    @Autowired
    private MongoService mongoService;

    public MongoServiceTest() throws UnknownHostException {
        mongoRule = new MongoRule();
    }

    @Test
    public void testMongoService() {
        final DBObject document = DBContract.getUniqueQuery("001");
        document.put(DBContract.RVARIABLES, "values");
        document.put(DBContract.PVARIABLES, "values");

        mongoService.putDocument(document);
    }

我认为测试中的失败是 

12:37:25.224 [main] INFO  c.s.business.persist.MongoService - host=null, port=0, database=null
java.lang.NullPointerException
    at com.business.persist.MongoServiceTest.testMongoService(MongoServiceTest.java:40)

这意味着 bean 无法从 local.properties 读取值

本地属性 

### === MongoDB interaction === ###
host="127.0.0.1"
port=27017
database=contract

我该如何解决？

更新 即使在为字段创建 setter/getter 之后，它似乎也没有读取值。我现在真是一头雾水。

更新01

添加 init() 方法并将其添加到 bean 后，它仍然不起作用。我什至没有看到记录消息
XML 

<bean id="mongoService" class="com.business.persist.MongoService" init-method="init"></bean>

MongoService

@Service
public class MongoService {

    @Value("#{mongoProperties['host']}")
    private String host;

    @Value("#{mongoProperties['port']}")
    private int port;

    @Value("#{mongoProperties['database']}")
    private String database;

    private Mongo mongo;

    private static final Logger LOGGER = LoggerFactory.getLogger(MongoService.class);

    public MongoService() {}

    public void init() throws UnknownHostException {
        LOGGER.info("host=" + host + ", port=" + port + ", database=" + database);
        mongo = new Mongo(host, port);
    }

    public void putDocument(@Nonnull final DBObject document) {
        LOGGER.info("inserting document - " + document.toString());
        mongo.getDB(database).getCollection(getCollectionName(document)).insert(document, WriteConcern.SAFE);
    }

我怎么能调试这个问题？

非常感谢！

4

1 回答 1

1

我在这里看到一个问题，您正在MongoService构造函数中实例化一个 Mongo 类，但是此时您的属性尚未基于local.properties文件注入，因此主机、端口和数据库的值在那里将为空。

相反，您可以做的是不在 Service 构造函数中实例化 Mongo 类，让属性以您的方式注入 MongoService ，然后将其创建为在设置属性后调用的 init 方法的一部分：

在 MongoService 中：

public void init(){
    mongo = new Mongo(host, port);
}

并在您的 bean 配置中：

<bean id="mongoService" class="com.business.persist.MongoService" init-method="init"></bean>
于 2012-06-29T21:12:38.243 回答