开发小技巧

编程小技巧

1. 将List<Object> 转换为 List<String>

List<User> userList;// [{"name":"wang","age":23},{"name":"liu","age":13}]
List<String> nameList=userList.stream()
    .map(t->t.getName())
    .collect(Collectors.toList());// ["wang","li"]

2. 将List转换为Map

Map<Long,user> userInfo=user.stream()
    .collect(Collectors.toMap(user::getId,Function.identity()));

3. Java将JSON对象或JSON数组转list对象

https://blog.csdn.net/superPojo/article/details/108793355

4.lambda 遍历List＜String＞替换成另外一个值

estateMaps.stream().map(e-> domainChange(e)).collect(Collectors.toList())

5.Java对象类型集合单独取出对象中一个属性成为集合或数组

List<String> stateNameList = dictEntityList.stream().map(DictEntity::getName).collect(Collectors.toList());

pg序列自动生成 bigserial

@EnumValue

https://baomidou.com/pages/8390a4/

单元测试

• jacoco插件配置生成单元测试覆盖率报告：https://blog.csdn.net/weixin_38384296/article/details/122655287

PG删库提示“There are 2 other sessions using the database”信息

1. select pg_terminate_backend(pid) from (select pid from pg_stat_activity where datname = '数据库名' ) a;
2. 删库