springmvc 查询问题

[sx32612254]

后台报错：
Servlet.service() for servlet [StaffSystem] in context with path [/StaffSystem] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause java.lang.NullPointerException

imp代码：

package com.etc.web.imp;

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

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import com.etc.web.model.User;
import com.etc.web.service.UserService;

public class UserServiceImp implements UserService{
	
	private JdbcTemplate jdbcTemplate;
	@Override
	public void save(User user) {
		// TODO Auto-generated method stub
		 jdbcTemplate.update("insert into user(username,pwd) values (?,?)",new Object[]{user.getUsername(),user.getPassword()});  
	}

	@Override
	public void del(User user) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void update(User user) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void searchAll() {
		// TODO Auto-generated method stub
	}
	public JdbcTemplate getJdbcTemplate() {  
        return jdbcTemplate;  
    }  
  
    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {  
        this.jdbcTemplate = jdbcTemplate;  
    }

	@Override
	public List<User> searchLogin(String username){
		// TODO Auto-generated method stub
		List<User> users = null;
		Object[] params = new Object[] { username }; 
		String sql = "select * from user where username = ?";
		users =  (List<User>) jdbcTemplate.queryForObject(sql, params, new UserRowMapper());
		return (users != null && users.size() > 0) ? users : null;
	}  
}

controller 代码：

package com.etc.web.controller;

import javax.servlet.http.HttpServletRequest;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.etc.web.imp.UserServiceImp;
import com.etc.web.model.User;
import com.etc.web.service.UserService;

@Controller
@RequestMapping("/user")  
public class UserController {
	UserService userService;  
	  @RequestMapping(value="/toIndex",method=RequestMethod.POST)  
	    public ModelAndView toIndex (HttpServletRequest request){
		  String username = request.getParameter("username");
//此行报错
		  userService.searchLogin(username);
		return new ModelAndView("/index"); 
	  }
		 
}

RowMapper:

package com.etc.web.imp;

import java.sql.ResultSet;
import java.sql.SQLException;

import org.springframework.jdbc.core.RowMapper;

import com.etc.web.model.User;

public class UserRowMapper implements RowMapper<User> {

	@Override
	public User mapRow(ResultSet rs, int value) throws SQLException {
		// TODO Auto-generated method stub
		User user = new User();
		user.setUsername(rs.getString("username"));
		user.setPassword(rs.getString("password"));
		return user;
	}   
}

spring-servlet配置

<?xml version="1.0" encoding="UTF-8"?>
  <beans xmlns="http://www.springframework.org/schema/beans"    
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"    
    xmlns:context="http://www.springframework.org/schema/context"    
    xmlns:mvc="http://www.springframework.org/schema/mvc"    
    xsi:schemaLocation="     
           http://www.springframework.org/schema/beans     
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd     
           http://www.springframework.org/schema/context     
           http://www.springframework.org/schema/context/spring-context-3.0.xsd    
           http://www.springframework.org/schema/mvc     
           http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> 
        
    <!-- 静态资源访问 -->
    <mvc:default-servlet-handler/>
    <!-- 扫描包 -->
    <context:component-scan base-package="com.etc.web.controller" />
    <!-- 添加注解驱动 -->  
    <mvc:annotation-driven />  
    
    <bean id="ViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
   
    <!-- apache.dbcp连接池的配置 -->  
    <bean id="dataSource"  
        class="org.apache.commons.dbcp.BasicDataSource"  
        destroy-method="close">  
        <property name="driverClassName"  
            value="com.mysql.jdbc.Driver">  
        </property>  
        <property name="url" value="jdbc:mysql://localhost:3306/test"></property>  
        <property name="username" value="root"></property>  
        <property name="password" value="123456"></property>  
        <property name="maxActive" value="100"></property>  
        <property name="maxIdle" value="30"></property>  
        <property name="maxWait" value="500"></property>  
        <property name="defaultAutoCommit" value="true"></property>  
    </bean>  
      
    <!-- jdbc注入 -->  
    <bean id="jdbcTemplate"  
        class="org.springframework.jdbc.core.JdbcTemplate">  
        <property name="dataSource">  
            <ref bean="dataSource" />  
        </property>  
    </bean>  
      
    <!-- dao注入 -->  
    <bean id="userService" class="com.etc.web.imp.UserServiceImp">  
        <property name="jdbcTemplate" ref="jdbcTemplate"></property>  
    </bean>
   </beans>

困扰一天了，求帮忙解决

[sx32612254]

求回复，这个问题卡了好久啊 谢谢

[萝卜精]

空指针异常，你的username是控制，后台输出一下，看一下结果

[sx32612254]

后台就是在 userService.searchLogin(username);这里报错，没有进serviceImp

[sx32612254]

断点进 InvocationTargetException.<init>(Throwable) line: 72 public InvocationTargetException(Throwable target) { super((Throwable)null); // Disallow initCause this.target = target; } 这个异常抛出

[子夜静舞]

@Autowired UserService userService; 你这个userService 没有注入

[菜 头]

UserService userService; 这东西没注入到controller中，给它添加setter和getter方法就好了

[qq_16082733]

@Controller @RequestMapping("/user") public class UserController { UserService userService; @RequestMapping(value="/toIndex",method=RequestMethod.POST) public ModelAndView toIndex (HttpServletRequest request){ String username = request.getParameter("username"); //此行报错 userService.searchLogin(username); return new ModelAndView("/index"); } }; 里面的 UserService userService; 少了注解 @Autowired

[qq_34935513]

应该就是没写自动注入@Autowired的原因，因为没有set，get方法，所以报错空指针了

[Intboy]

controller中的UserService userService; 加上注解@Autowired，然在你的service中也加上注解@Service("userService")

@Autowired
UserService userService;

@Service("userService")
public class UserServiceImp implements UserService{

[jwyzszh]

userService 要加上get set 方法