Spring boot学习整理

目录：

• 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：

    @Autowired
    public 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 {
    @Id
    private 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 {

    @Autowired
    private 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 {
    @Autowired
    private 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 {
    @Bean
    public RestTemplate restTemplate(ClientHttpRequestFactory factory) {
        return new RestTemplate(factory);
    }

    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory() {
        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
        factory.setReadTimeout(5000);// ms
        factory.setConnectTimeout(15000);// ms
        return 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 {

    @Autowired
    RestTemplate 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