把与数据库表对应的entity类中int改为Integer

“Invalid update: invalid number of sections. The number of sections contained in the table view after the update (1) must be equal to the number of sections contained in the table view before the upda

在src里面的build.gradle中plugins {id ‘com.android.application’}的上面加上buildscript {repositories {jcenter()}dependencies {classpath 'com.android.tools.build:gradle:7.1.3'}}

Java通过url获取二进制流文件再传给前端。