SpringBoot踩坑日记_公众号:Java Pro的技术博客_

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1.Closing JPA EntityManagerFactory for persistence unit 'default'错误导致springboot启动后终止

------------------->
2019-01-22 17:18:34.941  INFO 42978 --- [      Thread-13] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2019-01-22 17:18:34.945  INFO 42978 --- [      Thread-13] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2019-01-22 17:18:35.181  INFO 42978 --- [      Thread-13] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.
在依赖中添加spring-boot-starter-web

例如Gradle在build.gradle中添加
implementation 'org.springframework.boot:spring-boot-starter-web'
<------------------- 2019.1.22
2.Gradle加载依赖很慢，换成国内源
--------------->
repositories {
    //使用国内源下载依赖
    maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
    mavenCentral()
替换之后重新Gradle下

<----------------2019-01-23
3.Gradle加载出错，错误如下
startup failed:
build file '/Users/cuifuan/workspaces/springcloud-tools/tools-eureka/build.gradle': 4: all buildscript {} blocks must appear before any plugins {} blocks in the script
See https://docs.gradle.org/5.0/userguide/plugins.html#sec:plugins_block for information on the plugins {} block
 @ line 4, column 1.
   buildscript {
1 error
Open File
经过一番排查
//删去下面代码，如果存在，我也不知道为什么
plugins {
    id 'java'
4.feign依赖不存在
feign 声明式调用

Feign makes writing java http clients easier
之前安装依赖
dependencies{
    compile "org.springframework.cloud:spring-cloud-starter-feign"
    compile "org.springframework.cloud:spring-cloud-starter-eureka"
springboot2.0之后
dependencies {
    implementation "org.springframework.cloud:spring-cloud-starter-openfeign"
    implementation 'org.springframework.cloud:spring-cloud-starter-eureka-server'
5. com.netflix.client.ClientException: Load balancer does not have available server for client: sp
build.gradle
dependencies {
    implementation "org.springframework.cloud:spring-cloud-starter-openfeign"
//应是eureka-client
    implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
6.解决报错 javax.persistence.TransactionRequiredException: Executing an update/delete query
运行报错原因：少了一个注解：@Transactional ： 要求开启事物管理
                            springboot踩坑日记——  java.lang.IllegalStateException: PathVariable annotation was empty on param 0.
                             Feign报错:java.lang.IllegalStateException: PathVariable annotation was empty on param 0.错误日志:Error starting ApplicationContext. To display the conditions report re-run your application with ‘debug’ ...
                            python 给函数传对象 python 函数传递
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# 下面代码实现a、b变量的值交换
a, b =
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