Java从入门到实战之（29）Java 异常处理之练习

1、异常处理的方法

使用 System 类的 System.err.println() 来展示异常的处理方法?

class ExceptionDemo
{
    public static void main(String[] args) {
        try {
            throw new Exception("My Exception");
        } catch (Exception e) {
            System.err.println("Caught Exception");
            System.err.println("getMessage():" + e.getMessage());
            System.err.println("getLocalizedMessage():" + e.getLocalizedMessage());
            System.err.println("toString():" + e);
            System.err.println("printStackTrace():");
            e.printStackTrace();
        }
    }
}

结果：

"C:Program FilesJavajdk1.8.0_221injava.exe" "-javaagent:C:Program FilesJetBrainsIntelliJ IDEA 2019.3.3libidea_rt.jar=60857:C:Program FilesJetBrainsIntelliJ IDEA 2019.3.3in" -Dfile.encoding=UTF-8 -classpath "C:Program FilesJavajdk1.8.0_221jrelibcharsets.jar;C:Program FilesJavajdk1.8.0_221jrelibdeploy.jar;C:Program FilesJavajdk1.8.0_221jrelibextaccess-bridge-64.jar;C:Program FilesJavajdk1.8.0_221jrelibextcldrdata.jar;C:Program FilesJavajdk1.8.0_221jrelibextdnsns.jar;C:Program FilesJavajdk1.8.0_221jrelibextjaccess.jar;C:Program FilesJavajdk1.8.0_221jrelibextjfxrt.jar;C:Program FilesJavajdk1.8.0_221jrelibextlocaledata.jar;C:Program FilesJavajdk1.8.0_221jrelibext
ashorn.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunec.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunjce_provider.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunmscapi.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunpkcs11.jar;C:Program FilesJavajdk1.8.0_221jrelibextzipfs.jar;C:Program FilesJavajdk1.8.0_221jrelibjavaws.jar;C:Program FilesJavajdk1.8.0_221jrelibjce.jar;C:Program FilesJavajdk1.8.0_221jrelibjfr.jar;C:Program FilesJavajdk1.8.0_221jrelibjfxswt.jar;C:Program FilesJavajdk1.8.0_221jrelibjsse.jar;C:Program FilesJavajdk1.8.0_221jrelibmanagement-agent.jar;C:Program FilesJavajdk1.8.0_221jrelibplugin.jar;C:Program FilesJavajdk1.8.0_221jrelib
esources.jar;C:Program FilesJavajdk1.8.0_221jrelib
t.jar;C:appFlinkUdf	arget	est-classes;C:Usersdefaultuser0.m2
epositoryjunitjunit4.11junit-4.11.jar;C:Usersdefaultuser0.m2
epositoryorghamcresthamcrest-core1.3hamcrest-core-1.3.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-java-bridge_2.111.11.1flink-table-api-java-bridge_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-java1.11.1flink-table-api-java-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-java1.11.1flink-java-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapachecommonscommons-lang33.3.2commons-lang3-3.3.2.jar;C:Usersdefaultuser0.m2
epositoryorgapachecommonscommons-math33.5commons-math3-3.5.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-streaming-java_2.111.11.1flink-streaming-java_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-runtime_2.111.11.1flink-runtime_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-queryable-state-client-java1.11.1flink-queryable-state-client-java-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-hadoop-fs1.11.1flink-hadoop-fs-1.11.1.jar;C:Usersdefaultuser0.m2
epositorycommons-iocommons-io2.4commons-io-2.4.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-netty4.1.39.Final-11.0flink-shaded-netty-4.1.39.Final-11.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-jackson2.10.1-11.0flink-shaded-jackson-2.10.1-11.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-zookeeper-33.4.14-11.0flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:Usersdefaultuser0.m2
epositorycommons-clicommons-cli1.3.1commons-cli-1.3.1.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-actor_2.112.5.21akka-actor_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeconfig1.3.3config-1.3.3.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langmodulesscala-java8-compat_2.11.7.0scala-java8-compat_2.11-0.7.0.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-stream_2.112.5.21akka-stream_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositoryorg
eactivestreams
eactive-streams1.0.2
eactive-streams-1.0.2.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafessl-config-core_2.11.3.7ssl-config-core_2.11-0.3.7.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-protobuf_2.112.5.21akka-protobuf_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-slf4j_2.112.5.21akka-slf4j_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositoryorgclappergrizzled-slf4j_2.111.3.2grizzled-slf4j_2.11-1.3.2.jar;C:Usersdefaultuser0.m2
epositorycomgithubscoptscopt_2.113.5.0scopt_2.11-3.5.0.jar;C:Usersdefaultuser0.m2
epositoryorgxerialsnappysnappy-java1.1.4snappy-java-1.1.4.jar;C:Usersdefaultuser0.m2
epositorycom	witterchill_2.11.7.6chill_2.11-0.7.6.jar;C:Usersdefaultuser0.m2
epositorycom	witterchill-java.7.6chill-java-0.7.6.jar;C:Usersdefaultuser0.m2
epositoryorglz4lz4-java1.6.0lz4-java-1.6.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-guava18.0-11.0flink-shaded-guava-18.0-11.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-streaming-java_2.111.11.1flink-streaming-java_2.11-1.11.1-tests.jar;C:Usersdefaultuser0.m2
epositoryorgslf4jslf4j-api1.7.15slf4j-api-1.7.15.jar;C:Usersdefaultuser0.m2
epositorycomgooglecodefindbugsjsr3051.3.9jsr305-1.3.9.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkforce-shading1.11.1force-shading-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-planner-blink_2.111.11.1flink-table-planner-blink_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-scala_2.111.11.1flink-table-api-scala_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-scala-bridge_2.111.11.1flink-table-api-scala-bridge_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-runtime-blink_2.111.11.1flink-table-runtime-blink_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgcodehausjaninojanino3.0.9janino-3.0.9.jar;C:Usersdefaultuser0.m2
epositoryorgcodehausjaninocommons-compiler3.0.9commons-compiler-3.0.9.jar;C:Usersdefaultuser0.m2
epositoryorgapachecalciteavaticaavatica-core1.16.0avatica-core-1.16.0.jar;C:Usersdefaultuser0.m2
epositoryorg
eflections
eflections.9.10
eflections-0.9.10.jar;C:Usersdefaultuser0.m2
epositoryorgjavassistjavassist3.19.0-GAjavassist-3.19.0-GA.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-streaming-scala_2.111.11.1flink-streaming-scala_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-scala_2.111.11.1flink-scala_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langscala-reflect2.11.12scala-reflect-2.11.12.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langscala-library2.11.12scala-library-2.11.12.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langscala-compiler2.11.12scala-compiler-2.11.12.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langmodulesscala-xml_2.111.0.5scala-xml_2.11-1.0.5.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langmodulesscala-parser-combinators_2.111.0.4scala-parser-combinators_2.11-1.0.4.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-common1.11.1flink-table-common-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-core1.11.1flink-core-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-annotations1.11.1flink-annotations-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-metrics-core1.11.1flink-metrics-core-1.11.1.jar;C:Usersdefaultuser0.m2
epositorycomesotericsoftwarekryokryo2.24.0kryo-2.24.0.jar;C:Usersdefaultuser0.m2
epositorycomesotericsoftwareminlogminlog1.2minlog-1.2.jar;C:Usersdefaultuser0.m2
epositoryorgobjenesisobjenesis2.1objenesis-2.1.jar;C:Usersdefaultuser0.m2
epositoryorgapachecommonscommons-compress1.20commons-compress-1.20.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-asm-77.1-11.0flink-shaded-asm-7-7.1-11.0.jar;C:Usersdefaultuser0.m2
epositorycomalibabafastjson1.2.73fastjson-1.2.73.jar;C:Usersdefaultuser0.m2
epositoryorgslf4jslf4j-log4j121.7.7slf4j-log4j12-1.7.7.jar;C:Usersdefaultuser0.m2
epositorylog4jlog4j1.2.17log4j-1.2.17.jar;C:Usersdefaultuser0.m2
epository
etsfjson-libjson-lib2.4json-lib-2.4-jdk15.jar;C:Usersdefaultuser0.m2
epositorycommons-beanutilscommons-beanutils1.8.0commons-beanutils-1.8.0.jar;C:Usersdefaultuser0.m2
epositorycommons-collectionscommons-collections3.2.1commons-collections-3.2.1.jar;C:Usersdefaultuser0.m2
epositorycommons-langcommons-lang2.5commons-lang-2.5.jar;C:Usersdefaultuser0.m2
epositorycommons-loggingcommons-logging1.1.1commons-logging-1.1.1.jar;C:Usersdefaultuser0.m2
epository
etsfezmorphezmorph1.0.6ezmorph-1.0.6.jar;C:Usersdefaultuser0.m2
epositoryorgjsonjson20180813json-20180813.jar" Practice.Test1
Caught Exception
getMessage():My Exception
getLocalizedMessage():My Exception
toString():java.lang.Exception: My Exception
printStackTrace():
java.lang.Exception: My Exception
    at Practice.Test1.main(Test1.java:11)

Process finished with exit code 0

2、多个异常处理（多个catch)

对异常的处理：

1，声明异常时，建议声明更为具体的异常，这样可以处理的更具体

2,对方声明几个异常，就对应几个catch块， 如果多个catch块中的异常出现继承关系，父类异常catch块放在最下面

class Demo  
{  
    int div(int a,int b) throws ArithmeticException,ArrayIndexOutOfBoundsException//在功能上通过throws的关键字声明该功能可能出现问题  
    {  
        int []arr = new int [a];  
  
        System.out.println(arr[4]);//制造的第一处异常  
  
        return a/b;//制造的第二处异常  
    }  
}  
  
  
class ExceptionDemo  
{  
    public static void main(String[]args) //throws Exception  
    {  
        Demo d = new Demo();  
  
        try  
            {  
                int x = d.div(4,0);//程序运行截图中的三组示例 分别对应此处的三行代码  
                //int x = d.div(5,0);  
                //int x = d.div(4,1);  
                System.out.println("x="+x);   
        }  
        catch (ArithmeticException e)  
        {  
            System.out.println(e.toString());  
        }  
        catch (ArrayIndexOutOfBoundsException e)  
        {  
            System.out.println(e.toString());  
        }  
        catch (Exception e)//父类 写在此处是为了捕捉其他没预料到的异常 只能写在子类异常的代码后面  
                            //不过一般情况下是不写的   
        {  
            System.out.println(e.toString());  
        }  
          
  
  
        System.out.println("Over");  
    }  
  
}

结果：

java.lang.ArrayIndexOutOfBoundsException: 4
Over

3、Finally的用法

Java 中的 Finally 关键一般与try一起使用，在程序进入try块之后，无论程序是因为异常而中止或其它方式返回终止的，finally块的内容一定会被执行 。

以下实例演示了如何使用 finally 通过 e.getMessage() 来捕获异常（非法参数异常）？

public class ExceptionDemo2 {
   public static void main(String[] argv) {
      new ExceptionDemo2().doTheWork();
   }
   public void doTheWork() {
      Object o = null;
      for (int i=0; i<5; i++) {
         try {
            o = makeObj(i);
         }
         catch (IllegalArgumentException e) {
            System.err.println
            ("Error: ("+ e.getMessage()+").");
            return;   
         }
         finally {
            System.err.println("都已执行完毕");
            if (o==null)
            System.exit(0);
        }
        System.out.println(o); 
      }
   }
   public Object makeObj(int type) 
   throws IllegalArgumentException {
      if (type == 1)  
      throw new IllegalArgumentException
      ("不是指定的类型： " + type);
      return new Object();
   }
}

结果：

都已执行完毕
java.lang.Object@7852e922
Error: (不是指定的类型：1).
都已执行完毕

4、使用catch处理异常

使用 catch 来处理异常的方法？

public class Main {
    public static void main (String args[]) {
        int array[]={20,20,40};
        int num1=15,num2=10;
        int result=10;
        try{
            result = num1/num2;
            System.out.println("结果为 " +result);
            for(int i =5;i >=0; i--) {
                System.out.println ("数组的元素值为 " +array[i]);
            }
        }
        catch (Exception e) {
            System.out.println("触发异常 : "+e);
        }
    }
}

结果：

结果为 1
触发异常 : java.lang.ArrayIndexOutOfBoundsException: 5

5、多线程异常处理

package Practice;
/**
 * @program: FlinkUdf
 * @description: 文件目录
 * @author: BigData
 * @create: 2020-11-09 14:19
 **/
class  MyThread extends Thread
{
    @Override
    public void run() {
        System.out.println("Throwing in " +"MyThread");
        throw new RuntimeException();
    }
}
public class Test1 {
    public static void main(String[] args) {
        MyThread t=new MyThread();
        t.start();
        try {
            Thread.sleep(1000);
        }
        catch (Exception x)
        {
            System.out.println("Caught it" + x);
        }
    }
}

结果：

"C:Program FilesJavajdk1.8.0_221injava.exe" "-javaagent:C:Program FilesJetBrainsIntelliJ IDEA 2019.3.3libidea_rt.jar=61117:C:Program FilesJetBrainsIntelliJ IDEA 2019.3.3in" -Dfile.encoding=UTF-8 -classpath "C:Program FilesJavajdk1.8.0_221jrelibcharsets.jar;C:Program FilesJavajdk1.8.0_221jrelibdeploy.jar;C:Program FilesJavajdk1.8.0_221jrelibextaccess-bridge-64.jar;C:Program FilesJavajdk1.8.0_221jrelibextcldrdata.jar;C:Program FilesJavajdk1.8.0_221jrelibextdnsns.jar;C:Program FilesJavajdk1.8.0_221jrelibextjaccess.jar;C:Program FilesJavajdk1.8.0_221jrelibextjfxrt.jar;C:Program FilesJavajdk1.8.0_221jrelibextlocaledata.jar;C:Program FilesJavajdk1.8.0_221jrelibext
ashorn.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunec.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunjce_provider.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunmscapi.jar;C:Program FilesJavajdk1.8.0_221jrelibextsunpkcs11.jar;C:Program FilesJavajdk1.8.0_221jrelibextzipfs.jar;C:Program FilesJavajdk1.8.0_221jrelibjavaws.jar;C:Program FilesJavajdk1.8.0_221jrelibjce.jar;C:Program FilesJavajdk1.8.0_221jrelibjfr.jar;C:Program FilesJavajdk1.8.0_221jrelibjfxswt.jar;C:Program FilesJavajdk1.8.0_221jrelibjsse.jar;C:Program FilesJavajdk1.8.0_221jrelibmanagement-agent.jar;C:Program FilesJavajdk1.8.0_221jrelibplugin.jar;C:Program FilesJavajdk1.8.0_221jrelib
esources.jar;C:Program FilesJavajdk1.8.0_221jrelib
t.jar;C:appFlinkUdf	arget	est-classes;C:Usersdefaultuser0.m2
epositoryjunitjunit4.11junit-4.11.jar;C:Usersdefaultuser0.m2
epositoryorghamcresthamcrest-core1.3hamcrest-core-1.3.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-java-bridge_2.111.11.1flink-table-api-java-bridge_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-java1.11.1flink-table-api-java-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-java1.11.1flink-java-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapachecommonscommons-lang33.3.2commons-lang3-3.3.2.jar;C:Usersdefaultuser0.m2
epositoryorgapachecommonscommons-math33.5commons-math3-3.5.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-streaming-java_2.111.11.1flink-streaming-java_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-runtime_2.111.11.1flink-runtime_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-queryable-state-client-java1.11.1flink-queryable-state-client-java-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-hadoop-fs1.11.1flink-hadoop-fs-1.11.1.jar;C:Usersdefaultuser0.m2
epositorycommons-iocommons-io2.4commons-io-2.4.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-netty4.1.39.Final-11.0flink-shaded-netty-4.1.39.Final-11.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-jackson2.10.1-11.0flink-shaded-jackson-2.10.1-11.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-zookeeper-33.4.14-11.0flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:Usersdefaultuser0.m2
epositorycommons-clicommons-cli1.3.1commons-cli-1.3.1.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-actor_2.112.5.21akka-actor_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeconfig1.3.3config-1.3.3.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langmodulesscala-java8-compat_2.11.7.0scala-java8-compat_2.11-0.7.0.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-stream_2.112.5.21akka-stream_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositoryorg
eactivestreams
eactive-streams1.0.2
eactive-streams-1.0.2.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafessl-config-core_2.11.3.7ssl-config-core_2.11-0.3.7.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-protobuf_2.112.5.21akka-protobuf_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositorycom	ypesafeakkaakka-slf4j_2.112.5.21akka-slf4j_2.11-2.5.21.jar;C:Usersdefaultuser0.m2
epositoryorgclappergrizzled-slf4j_2.111.3.2grizzled-slf4j_2.11-1.3.2.jar;C:Usersdefaultuser0.m2
epositorycomgithubscoptscopt_2.113.5.0scopt_2.11-3.5.0.jar;C:Usersdefaultuser0.m2
epositoryorgxerialsnappysnappy-java1.1.4snappy-java-1.1.4.jar;C:Usersdefaultuser0.m2
epositorycom	witterchill_2.11.7.6chill_2.11-0.7.6.jar;C:Usersdefaultuser0.m2
epositorycom	witterchill-java.7.6chill-java-0.7.6.jar;C:Usersdefaultuser0.m2
epositoryorglz4lz4-java1.6.0lz4-java-1.6.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-guava18.0-11.0flink-shaded-guava-18.0-11.0.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-streaming-java_2.111.11.1flink-streaming-java_2.11-1.11.1-tests.jar;C:Usersdefaultuser0.m2
epositoryorgslf4jslf4j-api1.7.15slf4j-api-1.7.15.jar;C:Usersdefaultuser0.m2
epositorycomgooglecodefindbugsjsr3051.3.9jsr305-1.3.9.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkforce-shading1.11.1force-shading-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-planner-blink_2.111.11.1flink-table-planner-blink_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-scala_2.111.11.1flink-table-api-scala_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-api-scala-bridge_2.111.11.1flink-table-api-scala-bridge_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-runtime-blink_2.111.11.1flink-table-runtime-blink_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgcodehausjaninojanino3.0.9janino-3.0.9.jar;C:Usersdefaultuser0.m2
epositoryorgcodehausjaninocommons-compiler3.0.9commons-compiler-3.0.9.jar;C:Usersdefaultuser0.m2
epositoryorgapachecalciteavaticaavatica-core1.16.0avatica-core-1.16.0.jar;C:Usersdefaultuser0.m2
epositoryorg
eflections
eflections.9.10
eflections-0.9.10.jar;C:Usersdefaultuser0.m2
epositoryorgjavassistjavassist3.19.0-GAjavassist-3.19.0-GA.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-streaming-scala_2.111.11.1flink-streaming-scala_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-scala_2.111.11.1flink-scala_2.11-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langscala-reflect2.11.12scala-reflect-2.11.12.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langscala-library2.11.12scala-library-2.11.12.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langscala-compiler2.11.12scala-compiler-2.11.12.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langmodulesscala-xml_2.111.0.5scala-xml_2.11-1.0.5.jar;C:Usersdefaultuser0.m2
epositoryorgscala-langmodulesscala-parser-combinators_2.111.0.4scala-parser-combinators_2.11-1.0.4.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-table-common1.11.1flink-table-common-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-core1.11.1flink-core-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-annotations1.11.1flink-annotations-1.11.1.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-metrics-core1.11.1flink-metrics-core-1.11.1.jar;C:Usersdefaultuser0.m2
epositorycomesotericsoftwarekryokryo2.24.0kryo-2.24.0.jar;C:Usersdefaultuser0.m2
epositorycomesotericsoftwareminlogminlog1.2minlog-1.2.jar;C:Usersdefaultuser0.m2
epositoryorgobjenesisobjenesis2.1objenesis-2.1.jar;C:Usersdefaultuser0.m2
epositoryorgapachecommonscommons-compress1.20commons-compress-1.20.jar;C:Usersdefaultuser0.m2
epositoryorgapacheflinkflink-shaded-asm-77.1-11.0flink-shaded-asm-7-7.1-11.0.jar;C:Usersdefaultuser0.m2
epositorycomalibabafastjson1.2.73fastjson-1.2.73.jar;C:Usersdefaultuser0.m2
epositoryorgslf4jslf4j-log4j121.7.7slf4j-log4j12-1.7.7.jar;C:Usersdefaultuser0.m2
epositorylog4jlog4j1.2.17log4j-1.2.17.jar;C:Usersdefaultuser0.m2
epository
etsfjson-libjson-lib2.4json-lib-2.4-jdk15.jar;C:Usersdefaultuser0.m2
epositorycommons-beanutilscommons-beanutils1.8.0commons-beanutils-1.8.0.jar;C:Usersdefaultuser0.m2
epositorycommons-collectionscommons-collections3.2.1commons-collections-3.2.1.jar;C:Usersdefaultuser0.m2
epositorycommons-langcommons-lang2.5commons-lang-2.5.jar;C:Usersdefaultuser0.m2
epositorycommons-loggingcommons-logging1.1.1commons-logging-1.1.1.jar;C:Usersdefaultuser0.m2
epository
etsfezmorphezmorph1.0.6ezmorph-1.0.6.jar;C:Usersdefaultuser0.m2
epositoryorgjsonjson20180813json-20180813.jar" Practice.Test1
Exception in thread "Thread-0" java.lang.RuntimeException
    at Practice.MyThread.run(Test1.java:13)
Throwing in MyThread

Process finished with exit code 0

6、获取异常的堆栈信息

如何使用异常类的 printStack() 方法来获取堆栈信息？

public class Main{
    public static void main (String args[]){
        int array[]={20,20,40};
        int num1=15,num2=10;
        int result=10;
        try{
            result = num1/num2;
            System.out.println("The result is" +result);
            for(int i =5; i>=0; i--) {
                System.out.println("The value of array is" +array[i]);
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

结果：

The result is1
java.lang.ArrayIndexOutOfBoundsException: 5
        at testapp.Main.main(Main.java:28)

7、重载方法异常处理

public class Main {
    double method(int i) throws Exception{
        return i/0;
    }
    boolean method(boolean b) {
        return !b;
    }
    static double method(int x, double y) throws Exception  {
        return x + y ;
    }
    static double method(double x, double y) {
        return x + y - 3;
    }   
    public static void main(String[] args) {
        Main mn = new Main();
        try{
            System.out.println(method(10, 20.0));
            System.out.println(method(10.0, 20));
            System.out.println(method(10.0, 20.0));
            System.out.println(mn.method(10));
        }
        catch (Exception ex){
            System.out.println("exception occoure: "+ ex);
        }
    }
}

结果：

30.0
27.0
27.0
exception occoure: java.lang.ArithmeticException: / by zero

8、链式异常

public class Main {
    public static void main (String args[])throws Exception  {
        int n=20,result=0;
        try{
            result=n/0;
            System.out.println("结果为"+result);
        }
        catch(ArithmeticException ex){
            System.out.println("发算术异常: "+ex);
            try {
                throw new NumberFormatException();
            }
            catch(NumberFormatException ex1) {
                System.out.println("手动抛出链试异常 : "+ex1);
            }
        }
    }
}

结果：

发算术异常: java.lang.ArithmeticException: / by zero
手动抛出链试异常 : java.lang.NumberFormatException

9、自定义异常

通过继承 Exception 来实现自定义异常？

class WrongInputException extends Exception {  // 自定义的类
    WrongInputException(String s) {
        super(s);
    }
}
class Input {
    void method() throws WrongInputException {
        throw new WrongInputException("Wrong input"); // 抛出自定义的类
    }
}
class TestInput {
    public static void main(String[] args){
        try {
            new Input().method();
        }
        catch(WrongInputException wie) {
            System.out.println(wie.getMessage());
        }
    } 
}

结果：

Wrong input