springboot案例helloworld，分页插件

忘是亡心i 2022-04-23 00:40 240阅读 0赞

*  springboot项目打成war包：  
    参考 [https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/\#build-tool-plugins, ][https_docs.spring.io_spring-boot_docs_current_reference_htmlsingle_build-tool-plugins_][https://blog.csdn.net/qq\_33512843/article/details/80951741][https_blog.csdn.net_qq_33512843_article_details_80951741]

### 文章目录 ###

*  1, 配置pom.xml
 *  2， 配置Application.java和Controller类
 *   *  a, 自定义启动类Application.java
     *  b，controller类
 *  3, 分页插件
 *  4, 报错Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lan

![在这里插入图片描述][20190819161111215.png]

在idea下， 创建maven项目

# 1, 配置pom.xml #

<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.2.6.RELEASE</version>
    		<relativePath/> 
    	</parent>
    	<groupId>com.example</groupId>
    	<artifactId>demo</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<name>demo</name>
    	<packaging>war</packaging>
    	<description>Demo project for Spring Boot</description>
    
    	<properties>
    		<java.version>1.8</java.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-tomcat</artifactId>
    			 
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    
    
    
    			</plugin>
    		</plugins>
    		<finalName>springboot</finalName> 
    	</build>

# 2， 配置Application.java和Controller类 #

## a, 自定义启动类Application.java ##

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.builder.SpringApplicationBuilder;
    import org.springframework.boot.context.web.SpringBootServletInitializer;
    import org.springframework.context.annotation.ComponentScan;
    
    @SpringBootApplication
    //@ComponentScan("a") //扫描controller所在的包
    public class Application extends SpringBootServletInitializer { 
    
        public static void main(String[] args) throws Exception { 
            SpringApplication.run(Application.class, args);
        }
    
        @Override
        public SpringApplicationBuilder configure(SpringApplicationBuilder builder) { 
            // 设置启动类,用于独立tomcat运行的入口
            return builder.sources(Application.class);
        }
    }

## b，controller类 ##

package a;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.ResponseBody;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @Controller
    @RequestMapping("/hello")
    public class HelloController { 
    
        @RequestMapping(value = "/success", method = { RequestMethod.GET})
        @ResponseBody
        public String successModel(HttpServletRequest request, HttpServletResponse reponse) { 
            return "success";
        }
    }

# 3, 分页插件 #

<dependency>
        <groupId>com.github.pagehelper</groupId>
        <artifactId>pagehelper-spring-boot-starter</artifactId>
        <version>1.2.5</version>
    </dependency>
    
    //#### serviceImpl实现分页
    ArrayList<Map<String, Object>>  list = new ArrayList<Map<String, Object>>();
    try { 
        //分页参数
        Integer page_num = Integer.valueOf(map.get("page_num").toString());
        Integer page_size = Integer.valueOf(map.get("page_size").toString());
        PageHelper.startPage(page_num, page_size);
        //获取mapper返回的数据
        Map<String, Object> data = disMapper.getData();
        list.add(data);
    } catch (Exception e) { 
        e.printStackTrace();
        return "错误!"
    }
    PageInfo<Map<String, Object>> pageInfo = new PageInfo<>(list);
    return n "sucess";

# 4, 报错Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lan #

解决： 在打war包时，排除掉tomcat\*.jar, javax\*.jar， 然后再重新打包

[https_docs.spring.io_spring-boot_docs_current_reference_htmlsingle_build-tool-plugins_]: https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#build-tool-plugins
[https_blog.csdn.net_qq_33512843_article_details_80951741]: https://blog.csdn.net/qq_33512843/article/details/80951741
[20190819161111215.png]: /images/20220323/a0ab642693314e47bb32a513a8c0bd12.png