jdk8升级到jdk11如何升级的真实案例（亲身经历）

<maven.compiler.target>11</maven.compiler.target>
<maven.compiler.source>11</maven.compiler.source>
<java.version>11</java.version>
<spring-boot.version>2.1.6.RELEASE</spring-boot.version>
<lombok.version>1.18.12</lombok.version>

<dependency>
    <groupId>javax.xml.soap</groupId>
    <artifactId>javax.xml.soap-api</artifactId>
    <version>1.4.0</version>
</dependency>
<dependency>
    <groupId></groupId>
    <artifactId>jaxws-ri</artifactId>
    <version>2.3.3</version>
    <type>pom</type>
</dependency>
<dependency>
    <groupId>com.sun.xml.bind</groupId>
    <artifactId>jaxb-impl</artifactId>
    <version>2.3.0</version>
</dependency>
<dependency>
    <groupId>javax.xml.bind</groupId>
    <artifactId>jaxb-api</artifactId>
    <version>2.3.0</version>
</dependency>
<dependency>
    <groupId>javax.annotation</groupId>
    <artifactId>javax.annotation-api</artifactId>
    <version>1.3.2</version>
</dependency>
<dependency>
    <groupId>com.sun.activation</groupId>
    <artifactId>javax.activation</artifactId>
    <version>1.2.0</version>
</dependency>
<dependency>
    <groupId>com.sun.xml.bind</groupId>
    <artifactId>jaxb-core</artifactId>
    <version>2.3.0</version>
</dependency>
<dependency>
    <groupId>com.alibaba.jvm</groupId>
    <artifactId>java-migration-jdk-patch</artifactId>
    <version>0.3.1</version>
    <type>pom</type>
</dependency>
<dependency>
    <groupId>javax.transaction</groupId>
    <artifactId>javax.transaction-api</artifactId>
    <version>1.2</version>
</dependency>

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.2.4.Final</version>
</dependency>

去除
#SERVICE_OPTS="${SERVICE_OPTS} -XX:+UseConcMarkSweepGC -XX:+UseCMSCompactAtFullCollection -XX:CMSMaxAbortablePrecleanTime=5000"
#SERVICE_OPTS="${SERVICE_OPTS} -XX:+CMSClassUnloadingEnabled -XX:CMSInitiatingOccupancyFractinotallow=80 -XX:+UseCMSInitiatingOccupancyOnly"
#SERVICE_OPTS="${SERVICE_OPTS} -XX:+ExplicitGCInvokesConcurrent -Dsun.rmi.dgc.server.gcInterval=2592000000 -Dsun.rmi.dgc.client.gcInterval=2592000000"
#SERVICE_OPTS="${SERVICE_OPTS} -XX:ParallelGCThreads=4"
#SERVICE_OPTS="${SERVICE_OPTS} -Xloggc:${MIDDLEWARE_LOGS}/gc.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps"


SERVICE_OPTS="${SERVICE_OPTS} -XX:+UseG1GC -XX:+UseVtableBasedCHA -XX:+UseCompactObjectHeaders"
SERVICE_OPTS="${SERVICE_OPTS} -XX:G1HeapReginotallow=8m"
SERVICE_OPTS="${SERVICE_OPTS} -XX:+G1BarrierSkipDCQ"
SERVICE_OPTS="${SERVICE_OPTS} -Xlog:gc*:/home/admin/logs/gc.log:time"
SERVICE_OPTS="${SERVICE_OPTS} -XX:G1HeapWastePercent=2"
SERVICE_OPTS="${SERVICE_OPTS} -XX:+ExplicitGCInvokesConcurrent -Dsun.rmi.dgc.server.gcInterval=2592000000 -Dsun.rmi.dgc.client.gcInterval=2592000000"
if [ -n "$AJDK_MAX_PROCESSORS_LIMIT" ]; then
    SERVICE_OPTS="${SERVICE_OPTS} -XX:ActiveProcessorCount=$AJDK_MAX_PROCESSORS_LIMIT"
fi

String str = " i am lzc ";
boolean isblank = str.isBlank();         //判断字符串是空白
boolean isempty = str.isEmpty();         //判断字符串是否为空
String  result1 = str.strip();           //首位空白
String  result2 = str.stripTrailing();  //去除尾部空白
String  result3 = str.stripLeading();   //去除首部空白
String  copyStr = str.repeat(2);        //复制几遍字符串
long  lineCount = str.lines().count();  //行数统计


System.out.println(isblank);            //结果:false            
System.out.println(isempty);            //结果:false 
System.out.println(result1);            //结果:i am lzc 
System.out.println(result2);            //结果: i am lzc 
System.out.println(result3);            //结果:i am lzc  
System.out.println(copyStr);            //结果: i am lzc  i am lzc  
System.out.println(lineCount);          //结果:1

Path filePath = Files.writeString(Path.of("/temp/a.txt"), "Sample text");
String fileContent = Files.readString(filePath);
System.out.println(fileContent.equals("Sample text"));

//Stream，允许接受一个null值，计算count时，返回0
long count = Stream.ofNullable(null).count();
System.out.println(count); // 0




//方法都接受一个谓词来决定从流中放弃哪些元素
//通俗理解：从集合中删除满足条件的元素，直到不满足为止
List list1 = Stream.of(1, 2, 3, 2, 1)
        .dropWhile(n -> n < 3)
        .collect(Collectors.toList());
System.out.println(list1); // [3, 2, 1]


//方法都接受一个谓词来决定从流中选用哪些元素
//通俗理解：从集合中提取满足条件的元素，直到不满足为止
List list2 = Stream.of(1, 2, 3, 2, 1)
        .takeWhile(n -> n < 3)
        .collect(Collectors.toList());
System.out.println(list2); // [1, 2]

List list1 = List.of(1, 3, 5, 7);
List list2 = List.copyOf(list1);
System.out.println(list2); //结果: [1,3,5,7]


Map<Integer, String> map1 = Map.of(1, "a", 2, "b", 3, "c");
Map<Integer, String> map2 = Map.copyOf(map1);
System.out.println(map2); //结果: {1=a, 2=b, 3=c}

//新增orElseThrow，为空时抛异常
Object v2 = Optional.ofNullable(null).orElseThrow();      //结果:抛异常


//新增ifPresentOrElse，不为null执行第1个回调函数，为null时执行第2个回调函数
Optional.ofNullable(null).ifPresentOrElse(
        (x) -> {
            System.out.println("数据：" + x);
        }, () -> {
            System.out.println("数据不存在");
        });


//提供另一个Optionals 作为空Optionals的回调
Object v3 = Optional.ofNullable(null)
        .or(() -> Optional.of("fallback"))
        .get();   //结果:fallback
System.out.println(v3);

HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
    .uri(URI.create(uri))
    .build();
// 异步
client.sendAsync(request, HttpResponse.BodyHandlers.ofString())
    .thenApply(HttpResponse::body)
    .thenAccept(System.out::println)
    .join();


// 同步
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
System.out.println(response.body());