KETTLE封装

一、背景　　

　　每天好像都很忙碌，已经不记得上次写博客是什么时候，这两天公司项目一个特殊的组网环境，需要重新搭建了KETTLE的封装，实现java调用ETL完成数据抽取转换加载的一些功能，搞了这么这么久的ETL，没想到今天掉坑里了，浪费了小半天的时间，以前觉得写博客要记录一些重大突破的或者高频的技术点，经历了这次，决定把所有遇到的问题都记录一下，顺道分享一下技术实现。

二、问题

      1、kettle的java开发包里没有添加pom依赖，需要手动添加和组合，这就回到了最原始的项目开发模式，那问题也很突出了，jar包冲突或者jar包引入不合适

      2、kettle的java代码组件的适用

三、处理过程

      要搭建kettle的java运行环境首先要引入三个包：kettle-core、kettle-engine、kettle-dbdialog，maven引入方式如下： 

 1         <dependency>
 2             <groupId>pentaho-kettle</groupId>
 3             <artifactId>kettle-core</artifactId>
 4             <version>${kettle.version}</version>
 5         </dependency>
 6 
 7         <dependency>
 8             <groupId>pentaho-kettle</groupId>
 9             <artifactId>kettle-engine</artifactId>
10             <version>${kettle.version}</version>
11         </dependency>
12 
13         <dependency>
14             <groupId>pentaho-kettle</groupId>
15             <artifactId>kettle-dbdialog</artifactId>
16             <version>${kettle.version}</version>
17         </dependency>
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     然后封装ETL的执行代码：

 1 public class KettleUtil {
 2     static {
 3         try {
 4             // 初始化
 5             KettleEnvironment.init();
 6         } catch (Exception e) {
 7             e.printStackTrace();
 8             throw new BusinessBaseException(new BusinessExceptionDesc("etl:100001",BusinessExceptionDesc.SHOW_TYPE.ERROR,"ETL执行异常"));
 9         }
10     }
11     public static String runTransfer(Map<String,String> map, String ktrPath) {
12         Trans trans = null;
13         String json = null;
14         try {
15             // 转换元对象
16             TransMeta transMeta = new TransMeta(ktrPath);
17 
18             // 转换
19             trans = new Trans(transMeta);
20 
21             if(null != map){
22                 for (Map.Entry<String,String> entry : map.entrySet()){
23                     trans.setVariable(entry.getKey(),entry.getValue());
24                 }
25             }
26 
27             // 执行转换
28             trans.execute(null);
29 
30             // 记录最后一个步骤的数据
31             final List<RowMetaAndData> rows = new ArrayList<RowMetaAndData>();
32             RowListener rowListner = new RowListener() {
33                 public void rowWrittenEvent(RowMetaInterface rowMeta, Object[] row)
34                         throws KettleStepException {
35                     rows.add(new RowMetaAndData(rowMeta, row));
36                 }
37 
38                 public void rowReadEvent(RowMetaInterface arg0, Object[] arg1)
39                         throws KettleStepException {
40                 }
41 
42                 public void errorRowWrittenEvent(RowMetaInterface arg0,
43                                                  Object[] arg1) throws KettleStepException {
44                 }
45             };
46 
47             //获取ETL步数
48             List<StepMetaDataCombi> steps = trans.getSteps();
49 
50             //最后一个步骤名称
51             String stepname = steps.get(steps.size() - 1).stepname;
52 
53             //添加行监听
54             StepInterface stepInterface = trans.findRunThread(stepname);
55             stepInterface.addRowListener(rowListner);
56 
57             // 等待执行完毕
58             trans.waitUntilFinished();
59 
60             if(!rows.isEmpty()){
61                 if(rows.size() > 1){
62                     StringBuffer resultBuf = new StringBuffer();
63                     for(RowMetaAndData rmad : rows){
64                         String rowData = rmad.getString("resultData",null);
65                         if(null != rowData){
66                             resultBuf.append(rowData).append(",");
67                         }
68                     }
69                     if(resultBuf.length() > 0){
70                         resultBuf.deleteCharAt(resultBuf.length() - 1);
71                         json = "["+ resultBuf +"]";
72                     }
73                 }else if(rows.size() == 1){
74                     RowMetaAndData rmad = rows.get(0);
75                     json = rmad.getString("resultData", null);
76                 }
77             }
78 
79             // 抛出异常
80             if (trans.getErrors() > 0) {
81                 String message = KettleLogStore.getAppender().getBuffer(trans.getLogChannelId(), false).toString();
82                 throw new BusinessBaseException(new BusinessExceptionDesc("etl:100003",BusinessExceptionDesc.SHOW_TYPE.ERROR,message));
83             }
84             return json;
85         } catch (KettleException e) {
86             e.printStackTrace();
87             throw new BusinessBaseException(new BusinessExceptionDesc("etl:100002",BusinessExceptionDesc.SHOW_TYPE.ERROR,"ETL执行异常"));
88         }
89     }
90 }
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        这个时候启动项目是没有什么问题，当我们用一个单元测试的方式测试时，会发现有好多的类都找不到，很明显的错误就是class not found，按照缺失的类名可以去https://mvnrepository.com/搜索或者去KETTLE的安装目录下的lib面搜索都可以解决问题：

1 nested exception is java.lang.NoClassDefFoundError: com/google/common/util/concurrent/SettableFuture
2 java.lang.NoClassDefFoundError: org/mozilla/javascript/JavaScriptException
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 1 <dependency>
 2             <groupId>com.google.guava</groupId>
 3             <artifactId>guava</artifactId>
 4             <version>18.0</version>
 5         </dependency>
 6 
 7         <dependency>
 8             <groupId>org.apache.commons</groupId>
 9             <artifactId>commons-vfs2</artifactId>
10             <version>2.1</version>
11         </dependency>
12 
13         <dependency>
14             <groupId>commons-lang</groupId>
15             <artifactId>commons-lang</artifactId>
16             <version>2.6</version>
17         </dependency>
18 
19         <dependency>
20             <groupId>com.sun.mail</groupId>
21             <artifactId>javax.mail</artifactId>
22             <version>1.6.2</version>
23         </dependency>
24 
25         <dependency>
26             <groupId>com.cite</groupId>
27             <artifactId>jsonpath</artifactId>
28             <version>1.0</version>
29         </dependency>
30 
31         <dependency>
32             <groupId>com.googlecode.json-simple</groupId>
33             <artifactId>json-simple</artifactId>
34             <version>1.1</version>
35         </dependency>
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       其中有一个特别的类处理时有个陷阱，JavaScript组件调用时需要，会有一个异常java.lang.NoClassDefFoundError: org/mozilla/javascript/JavaScriptException，从错误很明显可以知道是缺少jar包，两种解决途径确定是那个包，在kettle的安装路径搜索javascript，会发现存在的包并没有包含JavaScriptException类，然后可以去maven仓库搜索，找到的结果是，下面这个包：

1 dependency>
2      <groupId>org.mozilla</groupId>
3       <artifactId>javascript</artifactId>
4       <version>1.7.2</version>
5 </dependency>
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      重新构建项目，然后测试，可以发现ETL是可以执行了的，这里就是坑所在了，看似好了，其实并没有真的好了，在JavaScript组件中如果有JSON和String的转换操作时，代码就会报错：

 1 Caused by: org.mozilla.javascript.EcmaError: ReferenceError: "JSON" is not defined. (script#4)
 2     at org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3654)
 3     at org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3632)
 4     at org.mozilla.javascript.ScriptRuntime.notFoundError(ScriptRuntime.java:3717)
 5     at org.mozilla.javascript.ScriptRuntime.name(ScriptRuntime.java:1692)
 6     at org.mozilla.javascript.gen.c1._c0(script:4)
 7     at org.mozilla.javascript.gen.c1.call(script)
 8     at org.mozilla.javascript.ContextFactory.doTopCall(ContextFactory.java:398)
 9     at org.mozilla.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3065)
10     at org.mozilla.javascript.gen.c1.call(script)
11     at org.mozilla.javascript.gen.c1.exec(script)
12     at org.pentaho.di.trans.steps.scriptvalues_mod.ScriptValuesMod.addValues(ScriptValuesMod.java:387)
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        是不是很无解，ETL在kettle工具中是可以执行的，代码中调用就会报错，其实问题还是出自JavaScript包引入有问题，再次排查kettle安装路径会发现，lib下面有一个js-1.7R3.jar的，命名真的很出奇啊，然后再maven中央仓库中搜索发现并没有这个版本的，本地长传引入重新执行OK了！

四、java代码组件使用分享

     组件的使用就贴一段数据解密的代码吧，大家自己体会，但有一点要注意哈，组件中使用的类全部需要import，缺失任何一个都会有下面类似的错误：

       java代码组件如下：

 1 import java.security.Key;
 2 import java.security.KeyFactory;
 3 import java.security.PrivateKey;
 4 import java.security.interfaces.RSAKey;
 5 import java.security.interfaces.RSAPrivateKey;
 6 import java.security.interfaces.RSAPublicKey;
 7 import java.security.spec.PKCS8EncodedKeySpec;
 8 import java.security.spec.X509EncodedKeySpec;
 9 import java.util.HashMap;
10 import java.util.Map;
11 import java.util.Base64;
12 import java.io.ByteArrayOutputStream;
13 import sun.misc.BASE64Decoder;
14 import javax.crypto.Cipher;
15 String resultData = null;
16 public boolean processRow(StepMetaInterface smi, StepDataInterface sdi) throws KettleException
17 {
18     if (first){
19       first = false;
20     }
21     Object[] r = getRow();
22     if (r == null) {
23       setOutputDone();
24       return false;
25     }
26 
27 
28     r = createOutputRow(r, data.outputRowMeta.size());
29     String encryptionData = get(Fields.In, "encryptionData").getString(r);
30     String key = get(Fields.In, "keyPrivate").getString(r);
31     try {
32          byte[] keyBytes = (new BASE64Decoder()).decodeBuffer(key);
33         PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
34         KeyFactory keyFactory = KeyFactory.getInstance("RSA");
35         PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
36 
37         resultData = decryptByPrivateKey(encryptionData,privateKey);
38     } catch (Exception e) {
39         throw new KettleException(e);
40     }
41 
42 
43     get(Fields.Out, "resultData").setValue(r, resultData);
44     putRow(data.outputRowMeta, r);
45     return true;
46 }
47 public static String decryptByPrivateKey(String data, Key privateKey) {
48     try {
49          data = data.replaceAll("%2B", "+");
50          data = data.replaceAll("%2F", "/");
51          data = data.replaceAll("%25", "%");
52          data = data.replaceAll("%3D", "=");
53          byte[] bytes = Base64.getUrlDecoder().decode(data);
54          return new String(decryptByPrivateKey(bytes, privateKey));
55      } catch (Exception e) {
56          throw new KettleException(e);
57      }
58 }
59 
60 public static byte[] decryptByPrivateKey(byte[] data, Key privateKey) throws Exception {
61      try {
62           Cipher cipher_d = Cipher.getInstance("RSA");
63           cipher_d.init(Cipher.DECRYPT_MODE, privateKey);
64 
65           //模长
66           int key_len = ((RSAKey) privateKey).getModulus().bitLength() / 8;
67 
68           ByteArrayOutputStream bout = new ByteArrayOutputStream(cipher_d.getOutputSize(data.length)); //输出缓冲区
69 
70           //分块加密
71           for (int i = 0; i < (data.length + key_len - 1) / key_len; i++) {
72               bout.write(cipher_d.doFinal(data, i * key_len,
73               Math.min(key_len,data.length - (i * key_len))));
74           }
75           return bout.toByteArray();
76       } catch (Exception e) {
77           throw new Exception("解密失败", e);
78       }
79 }
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原文地址：https://www.cnblogs.com/cymiao/p/12559397.html