上一篇我们说了使用jpa配置属性直接生成SQL全量脚本文件的方式,想重新了解可以看:springBoot+jpa根据实体类注解生成SQL文件。
这一篇是根据Hibernate的SchemaExport实现程序建表,具体的方案可以是写在main函数中直接执行,也可以注入在springBoot中,在项目启动时自动完成。这里首先介绍第一种。
本系列环境基于 springBoot1.5.8.RELEASE+jpa+Hibernate5.0+java8
最开始就在想既然可以通过配置spring.jpa.hibernate.ddl-auto=update
实现自动创建和更新数据库的表结构,就应该有办法通过程序创建全量SQL和增量SQL吧,通过搜索,找到了蛛丝马迹:
Configuration cfg = new Configuration().configure();
SchemaExport se = new SchemaExport(cfg);
se.create(true,true);
SchemExport(Configuration)
已经失效,就需要使用:ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure().build();
MetadataImplementor metadata = (MetadataImplementor) new MetadataSources( serviceRegistry ).buildMetadata();
SchemaExport schemaExport = new SchemaExport(metadata);
schemaExport.create(true, true);
但是这些默认方式都需要hibernate.cfg.xml
文件,对于本系列中本身使用注解的项目而言则无法直接使用。
在之后的寻找中,发现可以手动配置的这些属性:
Map<String, Object> settings = new HashMap<>();
settings.put("hibernate.dialect", DIALECT_CLASS);
settings.put("hibernate.physical_naming_strategy", "org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy");
settings.put("hibernate.implicit_naming_strategy", "org.springframework.boot.orm.jpa.hibernate.SpringImplicitNamingStrategy");
settings.put("hibernate.id.new_generator_mappings", false);
StandardServiceRegistry standardServiceRegistry = new StandardServiceRegistryBuilder().applySettings(settings)
.build();
MetadataSources metadata = new MetadataSources(standardServiceRegistry);
MetadataImplementor metadataImplementor = (MetadataImplementor) metadata.getMetadataBuilder().build();
SchemaExport schemaExport = new SchemaExport(metadataImplementor);
String outputFile = getOutputFilename(args);
schemaExport.setOutputFile(outputFile);
schemaExport.setDelimiter(";");
schemaExport.create(true, false);
但是这个目前尚无法根据entity中注解文件生成脚本,毕竟还没设置扫描的路径。现在通过反射过滤获取所需要的class列表:
String pattern = getPattern(args);
List<Class<?>> classes = getClassesByAnnotation(Entity.class, pattern);
classes.forEach(metadata::addAnnotatedClass);
涉及到的相关方法如下:
/**
* 根据运行mian函数时的输入路径参数获取扫描路径,
* 无输出时使用默认路径PATTERN
* @param args
*/
private static String getPattern(String[] args) {
String pattern = PATTERN;
if(args != null && args.length >= 3
&& StringUtils.hasText(args[2])) {
pattern = args[2];
}
return pattern;
}
/**
* 使用流过滤获取所需类的list
*/
private static List<Class<?>> getClassesByAnnotation(Class<? extends Annotation> annotation, String pattern) {
return getResources(pattern).stream()
.map(r -> metadataReader(r))
.filter(Objects::nonNull)
.filter(mr -> mr.getAnnotationMetadata().hasAnnotation(annotation.getName()))
.map(mr -> entityClass(mr))
.filter(Objects::nonNull)
.collect(Collectors.toList());
}
/**
* 获取与模式对应的资源信息。
* @param pattern
* @return
*/
private static List<Resource> getResources(String pattern) {
PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
Resource[] resources;
try {
resources = resolver.getResources(pattern);
} catch (IOException e) {
throw new RuntimeException(e);
}
return Arrays.asList(resources);
}
private static Class<?> entityClass(MetadataReader mr) {
String className = mr.getClassMetadata().getClassName();
Class<?> clazz;
try {
clazz = Class.forName(className);
} catch (ClassNotFoundException e) {
System.err.printf("%s Class not found", className);
return null;
}
return clazz;
}
private static MetadataReader metadataReader(Resource r) {
MetadataReader mr;
try {
mr = new SimpleMetadataReaderFactory().getMetadataReader(r);
} catch (IOException e) {
System.err.printf(e.getMessage());
return null;
}
return mr;
}
/**
*根据输入生成输出路径,无输入时使用默认路径SCHEMA_SQL
*/
private static String getOutputFilename(String[] args) {
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
String currentDate = sdf.format(Calendar.getInstance().getTime());
if(args != null && args.length > 0
&& StringUtils.hasText(args[0])) {
String customSchemaName = args[0];
if(customSchemaName.contains("%s")) {
return String.format(customSchemaName, currentDate);
}
return customSchemaName;
}
return String.format(SCHEMA_SQL, currentDate);
}
该方法运行期间根据扫描的路径可能会报一些类未找到等错误,但不会影响脚本的生成,如:
java.lang.ClassNotFoundException: org.springframework.hateoas.config.EnableHypermediaSupport$HypermediaType
[main] DEBUG org.springframework.core.type.classreading.AnnotationAttributesReadingVisitor - Failed to classload enum type while reading annotation metadata
java.lang.ClassNotFoundException: org.jboss.logging.annotations.Message$Format
DEBUG org.springframework.core.type.classreading.AnnotationAttributesReadingVisitor - Failed to classload enum type while reading annotation metadata
java.lang.ClassNotFoundException: org.jboss.logging.annotations.Message$Format
以上错误是在使用默认扫描路径PATTERN = "classpath*:**/*.class";
的情况下可能出现的,至于原因是在getClassesByAnnotation过程中扫描了项目中的jar及其类后未能匹配到一些类等。这也反映出了扫描范围的大小在于扫描路径的选取。
package com.windcoder.qycms.core.basis.test.Hibernate.ddl;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.boot.spi.MetadataImplementor;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.MySQL5InnoDBDialect;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.SimpleMetadataReaderFactory;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.StreamUtils;
import org.springframework.util.StringUtils;
import javax.persistence.Entity;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.annotation.Annotation;
import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.stream.Collectors;
/**
* 可以使用JPA Entity类生成DDL查询的类
* windcoder.com
* 生成成功,但DIALECT_CLASS获取不友好。
* 参考:https://gist.github.com/sbcoba/e4264f4b4217746767e682c61f9dc3a6
*/
public class JpaEntityDdlExport {
/**
* 要创建的文件名
*/
private static final String SCHEMA_SQL = "schema_%s.sql";
/**
* 域类路径位置(如果范围很宽,则只能找到带有@Entity的类)
*/
private final static String PATTERN = "classpath*:**/*.class";
/**
* 定义DB的DDL
* org.hibernate.dialect.* 包参考*
*
* - Oracle Oracle10gDialect.class
* - H2 H2Dialect.class
* ...
*
*/
private final static Class<? extends Dialect> DIALECT_CLASS = MySQL5InnoDBDialect.class;
public static void main(String[] args) {
createData(args);
}
/**
* 生成全量SQL脚本
* @param args
*/
public static void createData(String[] args){
Map<String, Object> settings = new HashMap<>();
settings.put("hibernate.dialect", DIALECT_CLASS);
settings.put("hibernate.physical_naming_strategy","org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy");
settings.put("hibernate.implicit_naming_strategy","org.springframework.boot.orm.jpa.hibernate.SpringImplicitNamingStrategy");
settings.put("hibernate.id.new_generator_mappings", false);
StandardServiceRegistry standardServiceRegistry = new StandardServiceRegistryBuilder()
.applySettings(settings)
.build();
MetadataSources metadata = new MetadataSources(standardServiceRegistry);
String pattern = getPattern(args);
List<Class<?>> classes = getClassesByAnnotation(Entity.class, pattern);
classes.forEach(metadata::addAnnotatedClass);
MetadataImplementor metadataImplementor = (MetadataImplementor) metadata.getMetadataBuilder().build();
SchemaExport schemaExport = new SchemaExport(metadataImplementor);
String outputFile = getOutputFilename(args);
schemaExport.setOutputFile(outputFile);
schemaExport.setDelimiter(";");
schemaExport.create(true, false);
}
private static String getPattern(String[] args) {
String pattern = PATTERN;
if(args != null && args.length >= 3
&& StringUtils.hasText(args[2])) {
pattern = args[2];
}
return pattern;
}
private static void appendMetaData(String outputFile, Map<String, Object> settings) {
String charsetName = "UTF-8";
File ddlFile = new File(outputFile);
try {
StringBuilder sb = new StringBuilder();
sb.append("/* Generate Environment\n");
for (Map.Entry<String, Object> entry : settings.entrySet()) {
sb.append(entry.getKey().toString() + ": " + entry.getValue() + "\n");
}
sb.append("*/\n");
String ddlFileContents = StreamUtils.copyToString(new FileInputStream(ddlFile), Charset.forName(charsetName));
sb.append(ddlFileContents);
FileCopyUtils.copy(sb.toString().getBytes(charsetName), ddlFile);
} catch (IOException e) {
e.printStackTrace();
}
}
private static List<Class<?>> getClassesByAnnotation(Class<? extends Annotation> annotation, String pattern) {
return getResources(pattern).stream()
.map(r -> metadataReader(r))
.filter(Objects::nonNull)
.filter(mr -> mr.getAnnotationMetadata().hasAnnotation(annotation.getName()))
.map(mr -> entityClass(mr))
.filter(Objects::nonNull)
.collect(Collectors.toList());
}
/**
* 获取与模式对应的资源信息。
* @param pattern
* @return
*/
private static List<Resource> getResources(String pattern) {
PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
Resource[] resources;
try {
resources = resolver.getResources(pattern);
} catch (IOException e) {
throw new RuntimeException(e);
}
return Arrays.asList(resources);
}
private static Class<?> entityClass(MetadataReader mr) {
String className = mr.getClassMetadata().getClassName();
Class<?> clazz;
try {
clazz = Class.forName(className);
} catch (ClassNotFoundException e) {
System.err.printf("%s Class not found", className);
return null;
}
return clazz;
}
private static MetadataReader metadataReader(Resource r) {
MetadataReader mr;
try {
mr = new SimpleMetadataReaderFactory().getMetadataReader(r);
} catch (IOException e) {
System.err.printf(e.getMessage());
return null;
}
return mr;
}
private static String getOutputFilename(String[] args) {
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
String currentDate = sdf.format(Calendar.getInstance().getTime());
if(args != null && args.length > 0
&& StringUtils.hasText(args[0])) {
String customSchemaName = args[0];
if(customSchemaName.contains("%s")) {
return String.format(customSchemaName, currentDate);
}
return customSchemaName;
}
return String.format(SCHEMA_SQL, currentDate);
}
}