cd /root
wget https://codeload.github.com/apache/hive/tar.gz/rel/release-3.1.1
wget --no-check-certificate https://mirrors.tuna.tsinghua.edu.cn/apache/hive/hive-2.3.9/apache-hive-2.3.9-src.tar.gz
wget --no-check-certificate https://mirrors.tuna.tsinghua.edu.cn/apache/hive/hive-3.1.2/apache-hive-3.1.2-src.tar.gz
cd /root
tar -zxvf release-3.1.1/apache-hive-2.3.9-src.tar.gz/apache-hive-3.1.2-src.tar.gz
cd /root/hive-rel-release-3.1.1/ql/src/java/org/apache/hadoop/hive/ql/udf
将自己的定义的UDF java文件上传的上面这个目录下 ：
进入udfjava文件,修改package -> org.apache.hadoop.hive.ql.udf ;
cd …/exec/
修改 vim FunctionRegistry.java
import org.apache.hadoop.hive.ql.udf.HomeWorkAdd_RandomUDF20211231;
修改静态代码块：static{
这里注意如果继承UDF，一定要有false参数，如果继承GenericUDF，则不用，否则会编译报错FunctionType类型转换异常
system.registerUDF(“substr”, HomeWorkAdd_RandomUDF20211231.class, false);
}
mvn clean package -DskipTests -Phadoop-2 -Pdist
编译完成如上；
cd packaging/target/
cp apache-hive-3.1.1-bin.tar.gz 到目标路径解压即可
