Spring boot学习整理

Springboot结合hbase
Springboot结合elasticsearch
Springboot结合RestTemplate处理Http请求
Springboot的maven相关
Springboot结合dubbox
Springboot的banner设定
Springboot结合Kafka

Springboot结合hbase

首先在pom中添加依赖

        <dependency><groupId>org.apache.hbase</groupId><artifactId>hbase-client</artifactId><version>1.2.0</version><exclusions><exclusion><groupId>org.slf4j</groupId><artifactId>slf4j-log4j12</artifactId></exclusion><exclusion><groupId>org.mortbay.jetty</groupId><artifactId>servlet-api-2.5</artifactId></exclusion><exclusion><groupId>org.mortbay.jetty</groupId><artifactId>servlet-api-2.5-6.1.14</artifactId></exclusion></exclusions></dependency><dependency><groupId>org.apache.hadoop</groupId><artifactId>hadoop-hdfs</artifactId><version>2.6.0</version><exclusions><exclusion><artifactId>servlet-api</artifactId><groupId>javax.servlet</groupId></exclusion></exclusions></dependency>

代码：

    @Autowiredpublic SearchDaoImpl(AppSettings appSettings){this.appSettings = appSettings;Configuration HBASE_CONFIG = new Configuration();//与hbase/conf/hbase-site.xml中hbase.zookeeper.quorum配置的值相同HBASE_CONFIG.set("hbase.zookeeper.quorum", appSettings.getHbasename());//与hbase/conf/hbase-site.xml中hbase.zookeeper.property.clientPort配置的值相同HBASE_CONFIG.set("hbase.zookeeper.property.clientPort", appSettings.getHbaseport());conf = HBaseConfiguration.create(HBASE_CONFIG);}

Springboot结合elasticsearch

1.maven设置

springboot的版本是1.5.1.RELEASE。这个版本springboot使用的ES版本是2.4.4，其依赖的guava是16.0.1

这里我们需要手动指定guava为18.0版本，否则会出现异常 java.lang.NoSuchMethodError: com.google.common.util.concurrent.MoreExecutors.directExecutor()Ljava/util/concu‌rrent/Executor

...<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-elasticsearch</artifactId></dependency><dependency><groupId>org.springframework.data</groupId><artifactId>spring-data-elasticsearch</artifactId></dependency><dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>18.0</version></dependency>....

2.修改配置，在application.properties中添加以下内容

###########  es setting  ###########
spring.data.elasticsearch.cluster-name=yq-cluster
spring.data.elasticsearch.cluster-nodes=node3.test.cn:9300,node4.test.cn:9300,node5.test.cn:9300
spring.data.elasticsearch.local=false
spring.data.elasticsearch.repositories.enabled=true

3.创建实体类(与ES中存储的内容格式对应)

package com.product;import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;@Document(indexName = "yuqing", type = "emp", shards = 3, replicas = 1, refreshInterval = "-1")
public class MyClient {@Idprivate String id;private String first_name;private String last_name;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getFirst_name() {return first_name;}public void setFirst_name(String first_name) {this.first_name = first_name;}public String getLast_name() {return last_name;}public void setLast_name(String last_name) {this.last_name = last_name;}}

4.建立资源库

import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;public interface ClientRepository extends ElasticsearchRepository<MyClient, String> {}

5.服务接口

public interface EsService {MyClient findClient(String id);
}

6.服务实现

import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
public class EsServiceImpl implements EsService {@Autowiredprivate ClientRepository clientDao;private static final org.slf4j.Logger LOG = LoggerFactory.getLogger(EsServiceImpl.class);public MyClient findClient(String id) {MyClient client = clientDao.findOne(id);LOG.info(" get cliente by id {} is {}", id, client);return client;}
}

7.应用

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;@RestController
@RequestMapping(value = "/es/")
public class EsController {@Autowiredprivate EsService esl;@RequestMapping(value = "test", method = RequestMethod.POST)public Object test(@RequestBody String id) {return esl.findClient(id);}
}

参考：Spring boot + elasticsearch的最简单实践

在实际使用中要注意，安装的es版本与springboot中引用的es版本不能有差异不能太大。

例如安装的是2.4.2的，那么api使用的2.4.x基本没问题，但如果引用5.x以上那肯定就不行了，会提示 None of the configured nodes are available

所以使用时要先看一下当前 spring-data-elasticsearch 所使用的es版本

Springboot结合RestTemplate处理Http请求

先定义config bean

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;@Configuration
public class RestTemplateConfig {@Beanpublic RestTemplate restTemplate(ClientHttpRequestFactory factory) {return new RestTemplate(factory);}@Beanpublic ClientHttpRequestFactory simpleClientHttpRequestFactory() {SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();factory.setReadTimeout(5000);// msfactory.setConnectTimeout(15000);// msreturn factory;}
}

应用

注：针对返回结果的序列化问题，目前没有找到方便快捷的方式，只好通过Object转HashMap的途径解决(虽然这种方法在属性多的情况下也比较复杂)

RestTemplate.getForObject虽然可以指定为业务类，但是转换始终有问题。

@RestController
@EnableAutoConfiguration
@Import(value = { RestTemplateConfig.class })
public class SpringRestTemplateApp {@AutowiredRestTemplate restTemplate;/*********** HTTP GET method *************/@RequestMapping("")public String hello() {String url = "http://localhost:8081/user";      HashMap<String,Object> user = (HashMap<String,Object>)restTemplate.getForObject(url, Object.class);        return user.get("name").toString();}@RequestMapping("/user")public User genUser() {User user = new User();user.setAge(18);user.setName("Ray");return user;}public class User {private int age;private String name;public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}}public static void main(String[] args) throws Exception {SpringApplication.run(SpringRestTemplateApp.class, args);}
}

如果想将返回结果转换为实体对象(比如前面代码中的User)，需要以字符串接收结果，然后再转换为对象。

不过java的json工具(我用的jackson)貌似不是很给力，也或许是我使用不当，总感觉比C#的差多了，转换个json都好麻烦，尤其是复杂对象的时候(嵌套多层类，并且有List)

先定义实体类,这里要注意的是，如果有嵌套的类，必须要定义为静态类

public class Company {@JsonIgnoreProperties(ignoreUnknown=true)public static class Employee {public Employee () {}private String name;public String  getName() {return name;}public void setName(String  name) {this.name= name;}}public Company () {}private List<Employee> emps;public List<Employee> getEmployees() {return emps;}public void setEmployees(List<Employee> Employees) {this.emps= Employees;}
}

转换

public class TransferTest {private static TransferTest instance;public static TransferTest instance() {if (instance == null) {instance = new TransferTest();}return instance;}public TransferTest() {　　　　 //只需要定义一次objectMapper = new ObjectMapper() {private com.fasterxml.jackson.databind.ObjectMapper jacksonObjectMapper = new com.fasterxml.jackson.databind.ObjectMapper();public <T> T readValue(String value, Class<T> valueType) {try {return jacksonObjectMapper.readValue(value, valueType);} catch (IOException e) {throw new RuntimeException(e);}}public String writeValue(Object value) {try {return jacksonObjectMapper.writeValueAsString(value);} catch (Exception e) {throw new RuntimeException(e);}}};}private Company doTransfer(String origin, String from, String to) throws UnirestException {String resp = restTemplate.getForObject(<url>,<data>,String.Class); //使用某种http工具类以字符串获取返回结果Company data = objectMapper.readValue(str, Company.class);return data ;}
}

真的感觉好麻烦/(ㄒoㄒ)/~~

Springboot的maven相关

在将springboot项目发布的时候我们都是用maven打包成jar包，然后使用 java -jar xxx.jar 直接启动

但是有时候发现执行之后会提示找不到启动程序。

解决方法：在pom文件中添加以下内容

    <build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>1.5.2.RELEASE</version><executions><execution><goals><goal>repackage</goal></goals></execution></executions></plugin></plugins></build>

Springboot的banner设定

Springboot的banner很容易设置，只需要将banner.txt文件加到 src/main/resources 目录下即可

这里给出一个码农保护神

${AnsiColor.BRIGHT_YELLOW}  //                          _ooOoo_                               //
//                         o8888888o                              //
//                         88" . "88                              //
//                         (| ^_^ |)                              //
//                         O\  =  /O                              //
//                      ____/`---'\____                           //
//                    .'  \\|     |//  `.                         //
//                   /  \\|||  :  |||//  \                        //
//                  /  _||||| -:- |||||-  \                       //
//                  |   | \\\  -  /// |   |                       //
//                  | \_|  ''\---/''  |   |                       //
//                  \  .-\__  `-`  ___/-. /                       //
//                ___`. .'  /--.--\  `. . ___                     //
//              ."" '<  `.___\_<|>_/___.'  >'"".                  //
//            | | :  `- \`.;`\ _ /`;.`/ - ` : | |                 //
//            \  \ `-.   \_ __\ /__ _/   .-` /  /                 //
//      ========`-.____`-.___\_____/___.-`____.-'========         //
//                           `=---='                              //
//      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^        //
//            佛祖保佑       永不宕机     永无BUG                    //  ${AnsiColor.BRIGHT_RED}
Application Version: ${application.version}${application.formatted-version}
Spring Boot Version: ${spring-boot.version}${spring-boot.formatted-version}

参考：https://blog.csdn.net/baochanghong/article/details/54286422

转载于:https://www.cnblogs.com/TiestoRay/p/6526448.html