我们有一个Spring测试执行监听器，它通过Spring的ResourceDatabasePopulator导入转储的MySQL表定义：
public class DBSetupExecutionListener extends AbstractTestExecutionListener {
...
@Override
public synchronized void beforeTestClass(TestContext testContext) {
...
// import the table definitions from a previously dumped file
ResourceDatabasePopulator populator = new ResourceDatabasePopulator();
populator.addScript(new ClassPathResource("some-table-definitions.sql"));
populator.execute(dataSource);
...
}
...
}
导入的MySQL转储文件确实看起来像这样（简化）：
/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
DROP TABLE IF EXISTS `someTable`;
CREATE TABLE `someTable`(
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`other_table_id` bigint(20) NOT NULL,
...
PRIMARY KEY (`id`)
KEY `FK_OTHERTABLE_ID`(`other_table_id`),
CONSTRAINT `FK_OTHERTABLE_ID` FOREIGN KEY (`other_table_id`) REFERENCES `otherTable`(`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
DROP TABLE IF EXISTS `otherTable`;
CREATE TABLE `otherTable`(
`id` bigint(20) NOT NULL AUTO_INCREMENT,
...
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
...
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
通过command line导入转储可以正常工作时，ResourceDatabasePopulator忽略了预处理程序指令，因此在创建实际的被引用表之前先创建引用表失败。更改表定义的顺序确实可以解决问题，但是对于多个表来说有点繁琐，尤其是当您将当前表定义转储到文件中时。
由于导入转储的SQL表定义是IMO的一项非常常见的任务，我想我在这里做错了。有没有办法告诉
ResourceDatabasePopulator遵守预处理指令，从而防止在执行脚本时检查外键？ 最佳答案
我遵循@ M.Deinum的建议，并实现了自己的ResourceDatabasePopulator版本。由于成员的范围有限，并且缺少获取这些字段的任何获取方法，因此很遗憾，从原始ResourceDatabasePopulator实现中进行了一些复制和粘贴。此类绝对不是设计用于支持子类化的。
以下是在我的用例中对我有用的当前解决方案。它不是完美的，可能是针对MySQL语句量身定制的，但至少可以完成工作。
import java.io.BufferedReader;
import java.io.IOException;
import java.lang.invoke.MethodHandles;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.EncodedResource;
import org.springframework.jdbc.datasource.init.DatabasePopulatorUtils;
import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;
import org.springframework.jdbc.datasource.init.ScriptUtils;
import org.springframework.jdbc.datasource.init.UncategorizedScriptException;
import org.springframework.util.StringUtils;
/**
* Populates, initializes, or cleans up a database using SQL scripts defined in
* external resources.
* <p>
* This implementation will clean up a given script by removing comments and processing instructions
* contained in the script and perform a table reordering based on defined foreign keys in a
* best-effort attempt.
*
* <ul>
* <li>Call {@link #addScript} to add a single SQL script location.
* <li>Call {@link #addScripts} to add multiple SQL script locations.
* <li>Consult the setter methods in this class for further configuration options.
* <li>Call {@link #populate} or {@link #execute} to initialize or clean up the
* database using the configured scripts.
* </ul>
*
* @author Keith Donald
* @author Dave Syer
* @author Juergen Hoeller
* @author Chris Beams
* @author Oliver Gierke
* @author Sam Brannen
* @author Chris Baldwin
* @author Roman Vottner
*
* @since 3.0
* @see DatabasePopulatorUtils
* @see ScriptUtils
*/
public class OrderedResourceDatabasePopulator extends ResourceDatabasePopulator {
private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
protected String sqlScriptEncoding;
/**
* Construct a new {@code OrderedResourceDatabasePopulator} with default settings.
*/
public OrderedResourceDatabasePopulator() {
/* no-op */
}
/**
* Construct a new {@code OrderedResourceDatabasePopulator} with default settings
* for the supplied scripts.
*
* @param scripts the scripts to execute to initialize or clean up the database
* (never {@code null})
*/
public OrderedResourceDatabasePopulator(Resource... scripts) {
this();
setScripts(cleanResource(scripts));
}
/**
* Construct a new {@code OrderedResourceDatabasePopulator} with the supplied values.
*
* @param continueOnError flag to indicate that all failures in SQL should be logged but not cause
* a failure
* @param ignoreFailedDrops flag to indicate that a failed SQL {@code DROP} statement can be
* ignored
* @param sqlScriptEncoding the encoding for the supplied SQL scripts; may be {@code null} or
* <em>empty</em> to indicate platform encoding
* @param scripts the scripts to execute to initialize or clean up the database (never {@code
* null})
*/
public OrderedResourceDatabasePopulator(boolean continueOnError, boolean ignoreFailedDrops,
String sqlScriptEncoding, Resource... scripts) {
super(continueOnError, ignoreFailedDrops, sqlScriptEncoding, scripts);
}
/**
* Add a script to execute to initialize or clean up the database.
*
* @param script the path to an SQL script (never {@code null})
*/
@Override
public void addScript(Resource script) {
super.addScript(cleanResource(script)[0]);
}
/**
* Add multiple scripts to execute to initialize or clean up the database.
*
* @param scripts the scripts to execute (never {@code null})
*/
@Override
public void addScripts(Resource... scripts) {
super.addScripts(cleanResource(scripts));
}
/**
* Set the scripts to execute to initialize or clean up the database, replacing any previously
* added scripts.
*
* @param scripts the scripts to execute (never {@code null})
*/
@Override
public void setScripts(Resource... scripts) {
super.setScripts(cleanResource(scripts));
}
/**
* Specify the encoding for the configured SQL scripts, if different from the platform encoding.
*
* @param sqlScriptEncoding the encoding used in scripts; may be {@code null} or empty to indicate
* platform encoding
*
* @see #addScript(Resource)
*/
@Override
public void setSqlScriptEncoding(String sqlScriptEncoding) {
super.setSqlScriptEncoding(sqlScriptEncoding);
this.sqlScriptEncoding = StringUtils.hasText(sqlScriptEncoding) ? sqlScriptEncoding : null;
}
private Resource[] cleanResource(Resource... scripts) {
List<Resource> cleaned = new ArrayList<>();
for (Resource script : scripts) {
EncodedResource encodedScript = new EncodedResource(script, this.sqlScriptEncoding);
StringBuilder sb = new StringBuilder();
try (BufferedReader in = new BufferedReader(encodedScript.getReader())) {
String line;
// parse script
Map<String, Table> tables = new LinkedHashMap<>();
Table curTable = null;
while ((line = in.readLine()) != null) {
if (!line.startsWith("#") && !line.startsWith("/*")) {
line = line.replaceAll("`", "");
String lowerCaseLine = line.toLowerCase();
// parse table definitions
if (lowerCaseLine.startsWith("drop table") || "".equals(line.trim())) {
if (curTable != null) {
curTable = null;
}
continue;
}
curTable = parseTable(line, tables, curTable);
}
}
// check the order of table definitions and reorder them to ensure referenced tables are
// defined before table specifying the foreign key
Map<String, Table> orderedTables = new LinkedHashMap<>();
List<Table> backlog = new ArrayList<>();
for (String tableName : tables.keySet()) {
// check for available foreign key definitions
List<String> referencedTables = tables.get(tableName).getReferencedTables();
// if no foreign keys are defined in the table we can add the table to the current set
if (referencedTables.isEmpty()) {
orderedTables.put(tableName, tables.get(tableName));
processBacklog(backlog, orderedTables);
continue;
}
// foreign keys are defined. If any of the referenced tables is not yet in the set move it
// to the backlog table and try it later
boolean dependenciesAvailable = true;
for (String dependency : referencedTables) {
if (!orderedTables.containsKey(dependency)) {
backlog.add(tables.get(tableName));
dependenciesAvailable = false;
break;
}
}
// if all referred tables are available in the set add the current table also to the
// ordered set
if (dependenciesAvailable) {
orderedTables.put(tableName, tables.get(tableName));
processBacklog(backlog, orderedTables);
continue;
}
// probe tables kept in the backlog again
processBacklog(backlog, orderedTables);
}
while (!backlog.isEmpty()) {
processBacklog(backlog, orderedTables);
}
ArrayList<Table> reverse = new ArrayList<>(orderedTables.values());
ListIterator<Table> reverseIter = reverse.listIterator(reverse.size());
sb.append("DROP TABLE IF EXISTS ");
int originalSize = sb.length();
while (reverseIter.hasPrevious()) {
if (sb.length() > originalSize) {
sb.append(", ");
}
sb.append(reverseIter.previous().getName());
}
sb.append(";\n\n");
for (Table table : orderedTables.values()) {
sb.append(table.getCreateStatement()).append("\n");
}
} catch (IOException ex) {
throw new UncategorizedScriptException(ex.getMessage(), ex);
}
if (LOG.isTraceEnabled()) {
LOG.trace("SQL script after cleaning: \n{}", sb.toString());
}
Resource cleanedResource = new ByteArrayResource(sb.toString().getBytes());
cleaned.add(cleanedResource);
}
return cleaned.toArray(new Resource[cleaned.size()]);
}
private Table parseTable(String line, Map<String, Table> tables, Table curTable) {
String lowerCaseLine = line.toLowerCase();
if (lowerCaseLine.startsWith("create table")) {
String name = line.substring("create table ".length(), line.indexOf("(")).trim();
curTable = new Table(name);
tables.put(name, curTable);
} else if (curTable != null) {
if (lowerCaseLine.contains("primary key")) {
curTable.setPrimaryKey(line);
} else if (lowerCaseLine.contains("unique key")) {
curTable.addUniqueKey(line);
} else if (lowerCaseLine.contains("foreign key")) {
curTable.addForeignKey(line);
} else if (lowerCaseLine.contains(" key ")) {
curTable.addIndex(line);
} else if (lowerCaseLine.contains(" charset=") || lowerCaseLine.contains("engine=")) {
curTable.setMetaData(line);
} else {
curTable.addColumn(line);
}
}
return curTable;
}
private void processBacklog(List<Table> backlog, Map<String, Table> orderedTables) {
Iterator<Table> iter = backlog.iterator();
while (iter.hasNext()) {
Table table = iter.next();
boolean allDependenciesAvailable = true;
for (String dependency : table.getReferencedTables()) {
if (!orderedTables.containsKey(dependency)) {
allDependenciesAvailable = false;
}
if (allDependenciesAvailable) {
orderedTables.put(table.getName(), table);
iter.remove();
}
}
}
}
private class Table {
private final String name;
private List<String> columns = new ArrayList<>();
private String primaryKey;
private List<String> uniqueKeys = new ArrayList<>();
private List<String> indices = new ArrayList<>();
private List<String> foreignKeys = new ArrayList<>();
private String metaData;
public Table(String name) {
this.name = name;
}
String getName() {
return this.name;
}
void addColumn(String column) {
this.columns.add(column);
}
void setPrimaryKey(String primaryKey) {
this.primaryKey = primaryKey;
}
void addUniqueKey(String uniqueKey) {
this.uniqueKeys.add(uniqueKey);
}
void addIndex(String index) {
this.indices.add(index);
}
void addForeignKey(String foreignKey) {
this.foreignKeys.add(foreignKey);
}
List<String> getReferencedTables() {
List<String> referencedTables = new ArrayList<>();
for (String foreignKey : foreignKeys) {
int start = foreignKey.toLowerCase().indexOf("references ") + "references ".length();
String table = foreignKey.substring(start, foreignKey.indexOf(" ", start));
referencedTables.add(table);
}
return referencedTables;
}
void setMetaData(String metaData) {
this.metaData = metaData;
}
String getCreateStatement() {
StringBuilder sb = new StringBuilder();
sb.append("CREATE TABLE ").append(this.name).append(" (");
for (String column : this.columns) {
sb.append("\n");
sb.append(" ").append(column);
}
if (null != primaryKey) {
sb.append("\n");
sb.append(" ").append(this.primaryKey);
}
if (!uniqueKeys.isEmpty()) {
for (String uniqueKey : uniqueKeys) {
sb.append("\n");
sb.append(" ").append(uniqueKey);
}
}
if (!indices.isEmpty()) {
for (String index : indices) {
sb.append("\n");
sb.append(" ").append(index);
}
}
if (!foreignKeys.isEmpty()) {
for (String foreignKey : foreignKeys) {
sb.append("\n");
sb.append(" ").append(foreignKey);
}
}
sb.append("\n");
if (metaData == null || !metaData.contains(")")) {
sb.append(") ");
}
if (metaData != null) {
sb.append(metaData);
}
sb.append("\n");
return sb.toString();
}
}
}
该填充器将首先清除给定脚本中的所有不需要的字符，注释或处理指令，然后构建一个虚拟表结构，以便在声明外部引用的表之前对作为外部引用目标的表进行排序。一旦表定义被虚拟化，填充器将通过以下方式重新创建脚本：首先以虚拟模型的正确顺序为每个表添加一个
DROP TABLE语句，然后以计算出的顺序添加CREATE TABLE语句。请注意，此版本尚不支持脚本中包含的其他SQL命令（例如
INSERT，...）。如果需要，请根据自己的喜好自定义此代码。为了使用重新排序的SQL脚本，只需将
ResourceDatabasePopulator替换为OrderedResourceDatabasePopulator@Override
public synchronized void beforeTestClass(TestContext testContext) {
...
// import the table definitions from a previously dumped file
ResourceDatabasePopulator populator = new OrderedResourceDatabasePopulator();
populator.addScript(new ClassPathResource("some-table-definitions.sql"));
populator.execute(dataSource);
...
}