给定一个目录，我的应用程序遍历并使用Jackcess API加载.mdb MS Access dbs。在每个数据库的内部，有一个名为GCMT_CMT_PROPERTIES的表，其中包含一个名为cmt_data的列，其中包含一些文本。我还有一个Mapper对象（基本上类似于Map<String,String>但允许重复键），当我从字符串替换某个单词时，我将其用作字典。
例如，如果mapper包含fox -> dog，则句子"The fox jumps"变为"The dog jumps"。
我参与此计划的设计如下：
1. Given a directory, traverse all subdirectories and load all .mdb files into a File[].
2. For each db file in File[], create a Task<Void> called "TaskMdbUpdater" and pass it the db file.
3. Dispatch and run each task as it is created (see 2. above).
TaskMdbUpdater负责在给定的db文件中查找相应的表和列，并迭代运行＆＃34; find＆amp;替换＆＃34;表的每一行上的例程，用于检测字典中的单词并替换它们（如上例所示），最后在关闭数据库之前更新该行。 TaskMdbUpdater的每个实例都是一个后台线程，其中分配了Jackcess API DatabaseBuilder，因此它可以操作数据库。
在当前状态下，代码运行时没有任何异常，但是当我＆＃34;手动＆＃34;通过Access打开数据库并检查给定的行，它似乎没有改变。我试图在没有任何运气的情况下确定问题的根源，并感谢任何支持。如果您需要查看更多代码，请告知我们，我会相应地更新我的问题。
public class TaskDatabaseTaskDispatcher extends Task<Void> {
private String parentDir;
private String dbFileFormat;
private Mapper mapper;
public TaskDatabaseTaskDispatcher(String parent, String dbFileFormat, Mapper mapper) {
this.parentDir = parent;
this.dbFileFormat = dbFileFormat;
this.mapper = mapper;
}
@Override
protected Void call() throws Exception {
File[] childDirs = getOnlyDirectories(getDirectoryChildFiles(new File(this.parentDir)));
DatabaseBuilder[] dbs = loadDatabasesInParent(childDirs);
Controller.dprint("TaskDatabaseTaskDispatcher", dbs.length + " databases were found in parent directory");
TaskMdbUpdater[] tasks = new TaskMdbUpdater[dbs.length];
Thread[] workers = new Thread[dbs.length];
for(int i=0; i<dbs.length; i++) {
// for each db, dispatch Task so a worker can update that db.
tasks[i] = new TaskMdbUpdater(dbs[i], mapper);
workers[i] = new Thread(tasks[i]);
workers[i].setDaemon(true);
workers[i].start();
}
return null;
}
private DatabaseBuilder[] loadDatabasesInParent(File[] childDirs) throws IOException {
DatabaseBuilder[] dbs = new DatabaseBuilder[childDirs.length];
// Traverse children and load dbs[]
for(int i=0; i<childDirs.length; i++) {
File dbFile = FileUtils.getFileInDirectory(
childDirs[i].getCanonicalFile(),
childDirs[i].getName() + this.dbFileFormat);
dbs[i] = new DatabaseBuilder(dbFile);
}
return dbs;
}
}
// StringUtils class, utility methods
public class StringUtils {
public static String findAndReplace(String str, Mapper mapper) {
String updatedStr = str;
for(int i=0; i<mapper.getMappings().size(); i++) {
updatedStr = updatedStr.replaceAll(mapper.getMappings().get(i).getKey(), mapper.getMappings().get(i).getValue());
}
return updatedStr;
}
}
// FileUtils class, utility methods:
public class FileUtils {
/**
* Returns only directories in given File[].
* @param list
* @return
*/
public static File[] getOnlyDirectories(File[] list) throws IOException, NullPointerException {
List<File> filteredList = new ArrayList<>();
for(int i=0; i<list.length; i++) {
if(list[i].isDirectory()) {
filteredList.add(list[i]);
}
}
File[] correctSizeFilteredList = new File[filteredList.size()];
for(int i=0; i<filteredList.size(); i++) {
correctSizeFilteredList[i] = filteredList.get(i);
}
return correctSizeFilteredList;
}
/**
* Returns a File[] containing all children under specified parent file.
* @param parent
* @return
*/
public static File[] getDirectoryChildFiles(File parent) {
return parent.listFiles();
}
}
public class Mapper {
private List<aMap> mappings;
public Mapper(List<aMap> mappings) {
this.mappings = mappings;
}
/**
* Returns mapping dictionary, typically used for extracting individual mappings.
* @return List of type aMap
*/
public List<aMap> getMappings() {
return mappings;
}
public void setMappings(List<aMap> mappings) {
this.mappings = mappings;
}
}
/**
* Represents a single String based K -> V mapping.
*/
public class aMap {
private String[] mapping; // [0] - key, [1] - value
public aMap(String[] mapping) {
this.mapping = mapping;
}
public String getKey() {
return mapping[0];
}
public String getValue() {
return mapping[1];
}
public String[] getMapping() {
return mapping;
}
public void setMapping(String[] mapping) {
this.mapping = mapping;
}
}
更新1：
为了验证我的自定义StringUtils.findAndReplace逻辑，我已经执行了以下单元测试（在JUnit中），该测试正在通过：
@Test
public void simpleReplacementTest() {
// Construct a test mapper/dictionary
List<aMap> aMaps = new ArrayList<aMap>();
aMaps.add(new aMap(new String[] {"fox", "dog"})); // {K, V} = K -> V
Mapper mapper = new Mapper(aMaps);
// Perform replacement
String corpus = "The fox jumps";
String updatedCorpus = StringUtils.findAndReplace(corpus, mapper);
assertEquals("The dog jumps", updatedCorpus);
}
我在这里分别包含我的TaskMdbUpdater课程，其中包含了一些日志记录代码，因为我怀疑失败点位于call：
/**
* Updates a given .mdb database according to specifications defined internally.
* @since 2.2
*/
public class TaskMdbUpdater extends Task<Void> {
private final String TABLE_NAME = "GCMT_CMT_PROPERTIES";
private final String COLUMN_NAME = "cmt_data";
private DatabaseBuilder dbPackage;
private Mapper mapper;
public TaskMdbUpdater(DatabaseBuilder dbPack, Mapper mapper) {
super();
this.dbPackage = dbPack;
this.mapper = mapper;
}
@Override
protected Void call() {
try {
// Controller.dprint("TaskMdbUpdater", "Worker: " + Thread.currentThread().getName() + " running");
// Open db and extract Table
Database db = this.dbPackage
.open();
Logger.debug("Opened database: {}", db.getFile().getName());
Table table = db.getTable(TABLE_NAME);
Logger.debug("Opening table: {}", table.getName());
Iterator<Row> tableRows = table.iterator();
// Controller.dprint("TaskMdbUpdater", "Updating database: " + db.getFile().getName());
int i=0;
try {
while( tableRows.hasNext() ) {
// Row is basically a<code> Map<Column_Name, Value> </code>
Row cRow = tableRows.next();
Logger.trace("Current row: {}", cRow);
// Controller.dprint(Thread.currentThread().getName(), "Database name: " + db.getFile().getName());
// Controller.dprint("TaskMdbUpdater", "existing row: " + cRow.toString());
String str = cRow.getString(COLUMN_NAME);
Logger.trace("Row {} column field contents (before find/replace): {}", i, str);
String newStr = performFindAndReplaceOnString(str);
Logger.trace("Row {} column field contents (after find/replace): {}", i, newStr);
cRow.put(COLUMN_NAME, newStr);
Logger.debug("Updating field in row {}", i);
Row newRow = table.updateRow(cRow); // <code>updateRow</code> returns the new, updated row. Ignoring this.
Logger.debug("Calling updateRow on table with modified row");
// Controller.dprint("TaskMdbUpdater", "new row: " + newRow.toString());
i++;
Logger.trace("i = {}", i);
}
} catch(NoSuchElementException e) {
// e.printStackTrace();
Logger.error("Thread has iterated past number of rows in table", e);
}
Logger.info("Iterated through {} rows in table {}", i, table.getName());
db.close();
Logger.debug("Closing database: {}", db.getFile().getName());
} catch (Exception e) {
// e.printStackTrace();
Logger.error("An error occurred while attempting to update row value", e);
}
return null;
}
/**
* @see javafx.concurrent.Task#failed()
*/
@Override
protected void failed() {
super.failed();
Logger.error("Task failed");
}
@Override
protected void succeeded() {
Logger.debug("Task succeeded");
}
private String performFindAndReplaceOnString(String str) {
// Logger.trace("OLD: [" + str + "]");
String updatedStr = null;
for(int i=0; i<mapper.getMappings().size(); i++) {
// loop through all parameter names in mapper to search for in str.
updatedStr = findAndReplace(str, this.mapper);
}
// Logger.trace("NEW: [" + updatedStr + "]");
return updatedStr;
}
}
这是我日志中的一个小问题。正如你所看到的，打开桌子之后似乎没有做任何事情让我感到有些困惑：
INFO (16-02-2017 17:27:59) [Thread-9] NAMEMAP.logic.TaskDatabaseTaskDispatcher.call(): Located the following directories under specified MOIS parent which contains an .mdb file:
[01_Parent_All_Safe_Test[ RV_DMS_0041RV_DMS_0001RV_DMS_0003RV_DMS_0005RV_DMS_0007RV_DMS_0012RV_DMS_0013RV_DMS_0014RV_DMS_0016RV_DMS_0017RV_DMS_0018RV_DMS_0020RV_DMS_0023RV_DMS_0025RV_DMS_0028RV_DMS_0029RV_DMS_0031RV_DMS_0033RV_DMS_0034RV_DMS_0035RV_DMS_0036RV_DMS_0038RV_DMS_0039RV_DMS_0040 ]]
...
DEBUG (16-02-2017 17:27:59) [Thread-9] NAMEMAP.logic.TaskDatabaseTaskDispatcher.call(): Created new task: NAMEMAP.logic.TaskMdbUpdater@4cfe46fe
DEBUG (16-02-2017 17:27:59) [Thread-9] NAMEMAP.logic.TaskDatabaseTaskDispatcher.call(): Created new worker: Thread[Thread-22,5,main]
DEBUG (16-02-2017 17:27:59) [Thread-9] NAMEMAP.logic.TaskDatabaseTaskDispatcher.call(): Set worker Thread[Thread-22,5,main] as daemon
DEBUG (16-02-2017 17:27:59) [Thread-9] NAMEMAP.logic.TaskDatabaseTaskDispatcher.call(): Dispatching worker: Thread[Thread-22,5,main]
...
DEBUG (16-02-2017 17:28:00) [Thread-22] NAMEMAP.logic.TaskMdbUpdater.call(): Opened database: RV_DMS_0023.mdb
DEBUG (16-02-2017 17:28:00) [Thread-22] NAMEMAP.logic.TaskMdbUpdater.call(): Opening table: GCMT_CMT_PROPERTIES
在此之后，日志中没有任何条目条目，并且处理器在100％负载时出现峰值，保持这种状态直到我强制终止应用程序。这可能意味着程序陷入无限循环 - 但如果情况确实如此，那么文件中是否应该有日志条目？
更新2
好的，我已将日志TRACE打印到stdio，从而进一步缩小了问题范围。似乎我的performFindAndReplaceOnString效率极低，而且它永远不会超过这些dbs的第一行，因为它只是在长弦上磨掉。关于如何有效地为此用例执行字符串替换的任何建议？