使用maven搭建web工程

1、新建maven工程，取名xiaoali

在pom.xml文件添加依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>

<groupId>xiaoali</groupId>
<artifactId>xiaoali</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>xiaoali</name>
<url>http://maven.apache.org</url>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring.version>4.3.9.RELEASE</spring.version>
<junit.version>4.12</junit.version>
</properties>

<dependencies>
<!-- 首先添加springmvc依赖包 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-expression</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-instrument</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-instrument-tomcat</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jms</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc-portlet</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-websocket</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>

因为使用maven clean整个工程后会出现jdk版本和自己在eclipse中配置的不一样，这时候需要在pom.xml中添加jdk版本控制插件

<build>
<finalName>xiaoali</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>

然后重新clean就可以了

2、配置web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>xiaotb</display-name>
<!-- 默认欢迎界面 -->
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>

<servlet>
<servlet-name>springMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springMVC</servlet-name>
<url-pattern>/</url-pattern>
<url-pattern>/xiaoali/login</url-pattern>
</servlet-mapping>

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-context.xml</param-value>
</context-param>
</web-app>

3、创建spring-context.xml和spring-mvc.xml文件

spring-context.xml

<?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:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"> <!--    ----------------------------------------------------------
进行扫描类包、读取配置文件、数据源管理、AOP配置、缓存以及消息队列等配置
---------------------------------------------------------- -->

<!-- 扫描类包，将标注Spring注解的类自动转化Bean，同时完成Bean的注入 -->
<context:component-scan base-package="com.xiaoali.controller" />
<context:component-scan base-package="com.xiaoali.service" />
<context:component-scan base-package="com.xiaoali.dao" />
</beans>

spring-mvc.xml

<?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:util="http://www.springframework.org/schema/util"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd">

<!-- 使用默认的注解映射 -->
<mvc:annotation-driven>
</mvc:annotation-driven>

</beans>

启动tomcat,报错

java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet

找不到类，原因是需要在工程中导入maven依赖jar包。导入完成后重启，没有报错信息显示。

4、输入访问地址

http://localhost:8080/xiaoali/login

控制台输出：

警告: No mapping found for HTTP request with URI [/xiaoali/login] in DispatcherServlet with name ‘springMVC’

原因：扫描类包的配置应该配置在spring-mvc.xml文件中，web.xml配置中Spring初始化参数是在spring-mvc.xml中，而不是在spring-context.xml，服务的启动首先加载spring-context.xml中的配置项，然后才初始化springframework

5、package创建

controller层

UserController.java

package com.xiaoali.controller;

import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import com.xiaoali.entity.User;
import com.xiaoali.service.UserService;

@Controller
public class UserController {

@Autowired
private UserService userService;

@RequestMapping(value= "/login")
@ResponseBody
public List<User> findUserList(){
List<User> userList = userService.findUserList();
for(User user : userList){
System.out.println(user.getName()+":"+user.getPwd());
}
return userList;
}
}

service层

接口类 UserService.java

package com.xiaoali.service;

import java.util.List;
import com.xiaoali.entity.User;

public interface UserService {

public List<User> findUserList();
}

实现类 UserServiceImpl.java

package com.xiaoali.service.impl;

import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.xiaoali.dao.UserDao;
import com.xiaoali.entity.User;
import com.xiaoali.service.UserService;

@Service
public class UserServiceImpl
implements UserService {

@Autowired
private UserDao userDao;
@Override
public List<User> findUserList() {
List<User> userList = userDao.findUserList();
return userList;
}

}

dao层

UserDao.java

package com.xiaoali.dao;

import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Repository;
import com.xiaoali.entity.User;

@Repository
public class UserDao {

private User user;

public List<User> findUserList(){
List<User> userList = new ArrayList<User>();
for(int i =0 ;i<3;i++){
user = new User();
user.setName("张三"+i);
user.setPwd("A"+i);
userList.add(user);
}
return userList;
}
}

entity层

User.java

package com.xiaoali.entity;

import java.io.Serializable;

public class User implements Serializable {

/**
*
*/
private static final long serialVersionUID = -5927908541432372896L;
private String name = "";
private String pwd = "";
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}

}

6、启动服务输入地址

http://localhost:8080/xiaoali/login

报错：严重: Servlet.service() for servlet [springmvc] in context with path [/xiaoali] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList] with root cause

java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList

原因：这是因为springmvc默认是没有对象转换成json的转换器的，需要手动添加jackson依赖。

解决：手动添加jackson依赖到pom.xml文件中

<jackson.version>2.8.9</jackson.version>

<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>

7、更新项目工程，重新导入maven依赖，重启服务

输入地址http://localhost:8080/xiaoali/login

访问成功，数据显示。



如果还是没有解决，在springmvc配置文件中进行如下配置

<mvc:annotation-driven>
<!--     <mvc:message-converters> -->
<!--             <bean class="org.springframework.http.converter.StringHttpMessageConverter"/> -->
<!--             <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/> -->
<!--     </mvc:message-converters> -->
</mvc:annotation-driven>

我这里注释掉了，因为我不需要。ヾ(◍°∇°◍)ﾉﾞ

后续：整合mybatis