微服务SpringCloud 第一节 Spring Boot

程序员文章站 2022-05-31 20:43:14

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研究微服务器框架SpringCloud，记录成果，以备后用。

Spring Cloud离不开SpringBoot 。Spring Cloud框架中的各个微服务都是由Spring Boot项目组成。

Spring Boot的出现，大大简化了Spring应用从创建到发布部署的整个过程：创建应用工程很简单；pom管理的jar包依赖井然有序；本身提供或者第三方提供的starter包很好用；大部分的配置都做了最符合习惯的默认设置，可以很少配置，甚至零配置（当然实际开发中开始需要做一些配置的）；内嵌web容器（tomcat，jetty)，部署发布只需要一个jar包等等。

Spring Boot就是由一个个starter组成。每个starter都包含至少一个完整的功能以及必要的jar依赖，starter帮助我们简化了pom依赖。

创建一个SpringBoot工程是非常简单的。以IDEA为例

创建一个project
选择Maven，SDK要选择1.8版本的JDK，因为SpringBoot不支持1.8以下的JDK版本。
设置GroupId和ArtifactId，最好用公司名称，这里只是举个栗子
选定工程目录
刚进来时是这样子的

修改pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>com.example</groupId>
    <artifactId>miniservice</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

	<name>miniservice</name>
	<description>Demo project for miniservice</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.3.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

   	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
		<com.alibaba.fastjson.version>1.2.47</com.alibaba.fastjson.version>
		
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
			<version>${fastjson.version}</version>
		</dependency>
	</dependencies>



</project>

spring-boot-starter-parent必不可少，它规定了Spring Boot的版本，以及依赖的统一管理。 lombok是一个java插件，我用来简写代码和统一风格，非常好用。

父pom创建好了，接下来，新建一个module：miniservice-demo。项目上点右键
生成miniservice-demo后，创建必要的java类,静态文件目录，html文件目录，配置文件application.properties。并修改module的pom.xml添加必要的依赖和打包插件。

package com.example.demo.configure;

import com.example.demo.util.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.NoHandlerFoundException;

import javax.servlet.http.HttpServletRequest;
import java.util.Map;

@ControllerAdvice
@Slf4j
public class GloabExceptionHandler {


    @ExceptionHandler(NoHandlerFoundException.class)
    @ResponseStatus(value = HttpStatus.NOT_FOUND)
    public ModelAndView  handleNotFoundException(HttpServletRequest request,
                                          NoHandlerFoundException ex) {
        handleLog(request, ex);
        ModelAndView view = new ModelAndView("error/404");
        view.addObject(Result.error( HttpStatus.NOT_FOUND.value(),ex==null?"":ex.getMessage()));
        return view;
    }
    @ExceptionHandler(Exception.class)
    @ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR)
    public ModelAndView handleAllException(HttpServletRequest request,
                                           Exception ex) {
        ModelAndView view = new ModelAndView("error/500");
        view.addObject(Result.error( HttpStatus.INTERNAL_SERVER_ERROR.value(),ex==null?"":ex.getMessage()));
        return view;
    }

    private void handleLog(HttpServletRequest request, Exception ex) {
        Map parameter = request.getParameterMap();
        StringBuffer logBuffer = new StringBuffer();
        if (request != null) {
            logBuffer.append("  request method=" + request.getMethod());
            logBuffer.append("  url=" + request.getRequestURL());
        }
        if (ex != null) {
            logBuffer.append("  exception:" + ex);
        }
        log.error(logBuffer.toString());
    }

}

<?xml version="1.0" encoding="UTF-8"?>
<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">
    <parent>
        <artifactId>miniservice</artifactId>
        <groupId>com.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>miniservice-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
    </dependencies>
    <build>
        <finalName>miniserviceDemo</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.example.demo.DemoApplication</mainClass>
                    <executable>true</executable>
                    <layout>ZIP</layout>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                            <goal>build-info</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

package com.example.demo.util;

import java.io.Serializable;

/**
 * 统一API响应结果封装
 */
public class Result<T> implements Serializable {
    private int code;
    private String message;
    private T data;
    public static final int SUCCESS = 200;

    public static final int FAIL = 400;
    public static final int NOT_FOUND = 404;

    public static final int ERROR = 500;

    public static final int NO_LOGIN = 300;

    public Result() {
    }
    public Result(int code, String msg, T data) {
        this.setCode(code);
        this.setMessage(msg);
        this.setData(data);
    }

    public void setCode(int code) {
        this.code = code;
    }

    public int getCode() {
        return code;
    }

    public String getMessage() {
        return message;
    }

    public Result setMessage(String message) {
        this.message = message;
        return this;
    }

    public T getData() {
        return data;
    }

    public Result setData(T data) {
        this.data = data;
        return this;
    }

    public static <T> Result<T> success() {
        return new Result<T>(SUCCESS, "success", null);
    }
    public static <T> Result<T> success(String message) {
        return new Result<T>(SUCCESS, message, null);
    }
    public static <T> Result<T> success(T data) {
        return new Result<T>(SUCCESS, "success", data);
    }
    public static <T> Result<T> success(String message, T data) {
        return new Result<T>(SUCCESS, message, data);
    }

    public static <T> Result<T> error() {
        return new Result<T>(ERROR, "fail", null);
    }
    public static <T> Result<T> clientfail() {
        return new Result<T>(ERROR, "clientfail", null);
    }
    public static <T> Result<T> error(int code,String errorMsg,T data) {
        return new Result<T>(code, errorMsg, data);
    }
    public static <T> Result<T> error(int code,String errorMsg) {
        return error(code,errorMsg,null);
    }

    public static <T> Result<T> error(String message) {
        return new Result<T>(ERROR, message, null);
    }
    public static <T> Result<T> error(T data) {
        return new Result<T>(ERROR, "fail", data);
    }
    public static <T> Result<T> error(String message, T data) {
        return new Result<T>(ERROR, message, data);
    }

    public static <T> Result<T> badrequest() {
        return new Result<T>(FAIL, "no identifier arguments", null);
    }
    public static <T> Result<T> badrequest(String message) {
        return new Result<T>(FAIL, message, null);
    }
    public static <T> Result<T> badrequest(T data) {
        return new Result<T>(FAIL, "no identifier arguments", data);
    }
    public static <T> Result<T> badrequest(String message, T data) {
        return new Result<T>(FAIL, message, data);
    }

    public static <T> Result<T> noLogin(String message) {
        return new Result<T>(NO_LOGIN, message, null);
    }

    public static <T> Result<T> notFound() {
        return new Result<T>(NOT_FOUND, "handler not found", null);
    }
}

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * @author : david.ye<br>
 * @version : v1.0
 * @Description :
 * @since : 2018/7/26 15:02<br>
 */
@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args){
        SpringApplication.run(DemoApplication.class,args);
    }  
}

package com.example.demo.controller;

import org.apache.catalina.util.RequestUtil;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.NoHandlerFoundException;

import javax.servlet.http.HttpServletRequest;

/**
 * @author : david.ye<br>
 * @version : v1.0
 * @Description :
 * @since : 2018/7/26 15:14<br>
 */
@Controller
@RequestMapping("/demo")
public class DemoController {
    @GetMapping("/{code}")
    public String validErrorPage(@PathVariable(name = "code")int code, HttpServletRequest request) throws Exception {
        if(code==200){
            request.setAttribute("message",code+"这是demo页面！！！！！");
            return "demo";
        }else if(code==404){
            throw new NoHandlerFoundException(request.getMethod(),request.getRequestURI(),null);
        }else{
            throw new Exception();
        }

    }
}

application.properties

#异常信息自定义
spring.mvc.throw-exception-if-no-handler-found=true
#编码
spring.http.encoding.force=true
spring.http.encoding.charset=UTF-8
spring.http.encoding.enabled=true
server.tomcat.uri-encoding=UTF-8
#port
server.port=8080

执行main方法，启动工程访问http://localhost:8080/demo/200，页面如下所示微服务SpringCloud 第一节 Spring Boot

试试访问一个随意的链接http://localhost:8080/demo：微服务SpringCloud 第一节 Spring Boot

备注：自定义的错误页404一定要放到templates/error下面否则@ControllerAdvice会拦截不到404错误

附件下载：miniservice.rar

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