Question

我需要在MYSQL中设置cookie并存储cookie - 密钥，值和时间戳。

因此，我有一个CookieUtil.java来设置（addCookie）并获取cookie。然后我创建了一个CookieEntity.java并将其映射到DAO层 - 接口和实现。我在int noOfRows = namedParameterJdbcTemplate.update(SQL,namedParameters);处有空指针。似乎namedParameterJdbcTemplate为null。但我真的无法弄清楚为什么？

CookieEntity.java

import java.sql.Timestamp;

public class EWPCookieEntity {

private String key;
private String value;
private Timestamp timeStamp;
//.... setters and getters
}

CookieDao.java接口

public boolean saveCookie(CookieEntity reqCookie);

CookieDaoImpl.java

package com......dao.impl;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Logger;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.stereotype.Repository;

import com......CookieDao;
import com......CookieEntity;
@Repository
public class CookieDaoImpl implements CookieDao{

@Autowired(required=false)
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

private String FETCH_USER_DETAILS_QUERY = "fetch.user.query";

private static Logger logger = Logger.getLogger(CookieDaoImpl.class.getName());

@Override
public boolean saveCookie(CookieEntity reqCookie) {
    String SQL = "insert into cookie_details(KEY, VALUE, TIMESTAMP) VALUES (:key, :value, :timeStamp)";

    Map<String,String > namedParameters = new HashMap<String, String>();
    namedParameters.put("key", reqCookie.getKey());
    namedParameters.put("value", reqCookie.getValue());
    //namedParameters.put("timeStamp", reqCookie.getTimeStamp());

    int noOfRows = namedParameterJdbcTemplate.update(SQL,namedParameters);
    System.out.println(noOfRows);
    logger.info("Cookie Details Saved: [ " + reqCookie.toString() + " ]");
    return noOfRows > 0 ? true : false;
}

@Override
public List<CookieEntity> getCookieValue(String key) {

    return null;
}

@Override
public int deleteCookie(String key) {

    return 0;
}

@SuppressWarnings("unused")
private void mapFromCookieDetailsResultSet(final CookieEntity cookieEntity, final ResultSet resultSet) {

    try {
        cookieEntity.setKey(resultSet.getString("KEY"));
        cookieEntity.setValue(resultSet.getString("VALUE"));
        cookieEntity.setTimeStamp(resultSet.getTimestamp("TIMESTAMP"));


    } catch (SQLException se) {

        if (logger.isDebugEnabled()) {
            logger.debug(
                    "**** Class UserDetailsDaoImpl **** Method mapFromUserDetailsResultSet **** SQLException Occured : "
                            + se.getMessage());
        }

    } catch (Exception e) {

        if (logger.isDebugEnabled()) {
            logger.debug(
                    "**** Class UserDetailsDaoImpl **** Method mapFromUserDetailsResultSet **** Exception Occured : "
                            + e.getMessage());
        }

    }
}

/**
  * @param namedParameterJdbcTemplate the namedParameterJdbcTemplate to set
  */
 public void setNamedParameterJdbcTemplate(NamedParameterJdbcTemplate namedParameterJdbcTemplate) {
  this.namedParameterJdbcTemplate = namedParameterJdbcTemplate;
 }

}

我的堆栈跟踪是：

 SEVERE: Servlet.service() for servlet [SimulatorServlet] in context with   path [/abc] 
      threw exception [Request processing failed; nested exception                
      java.lang.NullPointerException] with root cause
      java.lang.NullPointerException
at com....CookieDaoImpl.saveCookie(CookieDaoImpl.java:36)
at com......LoginController.doLogin(LoginController.java:69)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)

我的root_context.xml

<!-- JdbcTemplate -Starts -->
 <bean id = "jdbcTemplate" class =    "org.springframework.jdbc.core.JdbcTemplate">
<property name="fetchSize" value = "100"/>
<property name="dataSource" ref = "appDataSource"/>
</bean>

 <!-- JdbcTemplate -Ends -->

 <!-- NamedParameterJdbcTemplate -Starts -->
 <bean id = "namedParameterJdbcTemplate" class =  "org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
<constructor-arg ref="jdbcTemplate"/>
  </bean>

  <!-- NamedParameterJdbcTemplate -ends -->

Answer 1

您可以在<context:annotation-config />中添加root_context.xml以使@Autowired正常工作或者，如果您打算使用<context:component-scan base-package="your.package"/>，root_context.xml等注释，则可以在@Service中添加@Component。后者已经包含了第一个注释。

插入数据库时空指针

1 个答案:

插入数据库时​​空指针

1 个答案:

插入数据库时空指针