我正在尝试在JSONUserType上映射表格的一列。
我有模特：
@Entity
@TypeDefs({ @TypeDef(name = "JSONUserType", typeClass = JSONUserType.class) })
@Table( name = "my_table")
public class MyClass {
....
.....
@Column(name = "permissions")
@Type(type = "JSONUserType", parameters = { @Parameter(name = "classType",
value = "java.util.HashMap") })
private Map<String, Boolean> permissions;
......
......
Getter and setter
.....
.....
}
我实现了JSONUserType：
package it......model;
import java.io.IOException;
import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Objects;
import java.util.Properties;
import org.hibernate.HibernateException;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.internal.util.ReflectHelper;
import org.hibernate.usertype.ParameterizedType;
import org.hibernate.usertype.UserType;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
/**
* Hibernate {@link UserType} implementation to handle JSON objects
*
* @see https://docs.jboss.org/hibernate/orm/4.1/javadocs/org/hibernate/usertype/ UserType.html
*/
public class JSONUserType implements UserType, ParameterizedType, Serializable {
private static final long serialVersionUID = 1L;
private static final ObjectMapper MAPPER = new ObjectMapper()
// do NOT serialize null properties
.setSerializationInclusion(Include.NON_NULL)
// serialize dates using ISO format instead of epoch time
.setDateFormat(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"));
private static final String CLASS_TYPE = "classType";
private static final String COLLECTION_CLASS_TYPE = "collectionClassType";
private static final int[] SQL_TYPES = new int[] { Types.JAVA_OBJECT };
private Class<?> classType;
private Class<?> collectionClassType;
private int sqlType = Types.LONGVARCHAR; // before any guessing
@Override
public void setParameterValues(Properties params) {
// Retrieve the class name from params
String classTypeName = params.getProperty(CLASS_TYPE);
try {
// Retrieve the classType by reflection
classType = ReflectHelper.classForName(classTypeName, this.getClass());
// If class is a collection, we may have to retrieve the classType of its elements
if (Collection.class.isAssignableFrom(classType)) {
// Retrieve the elements class name from params
String collectionClassTypeName = params.getProperty(COLLECTION_CLASS_TYPE);
if (collectionClassTypeName != null) {
try {
// Retrieve the elements classType by reflection
collectionClassType = ReflectHelper.classForName(collectionClassTypeName, this.getClass());
}
catch (ClassNotFoundException e) {
throw new HibernateException("collectionClassType not found : " + collectionClassTypeName, e);
}
}
}
}
catch (ClassNotFoundException e) {
throw new HibernateException("classType not found : " + classTypeName, e);
}
sqlType = Types.OTHER;
}
@Override
public Object assemble(Serializable cached, Object owner) throws HibernateException {
return deepCopy(cached);
}
@Override
public Object deepCopy(Object value) throws HibernateException {
Object copy = null;
if (value != null) {
try {
return MAPPER.readValue(MAPPER.writeValueAsString(value), classType);
}
catch (IOException e) {
throw new HibernateException("unable to deep copy object", e);
}
}
return copy;
}
@Override
public Serializable disassemble(Object value) throws HibernateException {
try {
return MAPPER.writeValueAsString(value);
}
catch (JsonProcessingException e) {
throw new HibernateException("unable to disassemble object", e);
}
}
@Override
public boolean equals(Object x, Object y) throws HibernateException {
if (x == null && y == null) return true;
if (x == null) return false;
if (y == null) return false;
try {
return MAPPER.writeValueAsString(x).equals(MAPPER.writeValueAsString(y));
}
catch (JsonProcessingException e) {
}
return false;
}
@Override
public int hashCode(Object x) throws HibernateException {
return Objects.hash(x);
}
@Override
public boolean isMutable() {
return true;
}
@Override
public Object nullSafeGet(ResultSet rs, String[] names, SharedSessionContractImplementor session, Object owner) throws HibernateException, SQLException {
if (rs.getString(names[0]) == null) return null;
Object obj = null;
try {
// If we have defined a class type for the collection elements, cast JSON string to Collection<collectionClassType>
if (collectionClassType != null) {
obj = MAPPER.readValue(rs.getString(names[0]), MAPPER.getTypeFactory().constructCollectionType((Class<? extends Collection>) classType, collectionClassType));
}
// Else simply cast JSON string to classType
else {
obj = MAPPER.readValue(rs.getString(names[0]), classType);
}
}
catch (IOException e) {
throw new HibernateException("unable to read object from result set", e);
}
return obj;
}
@Override
public void nullSafeSet(PreparedStatement st, Object value, int index, SharedSessionContractImplementor session) throws HibernateException, SQLException {
if (value == null) {
st.setNull(index, sqlType);
} else {
try {
st.setObject(index, MAPPER.writeValueAsString(value), sqlType);
}
catch (JsonProcessingException e) {
throw new HibernateException("unable to set object to result set", e);
}
}
}
@Override
public Object replace(Object original, Object target, Object owner) throws HibernateException {
return deepCopy(original);
}
@Override
public Class<?> returnedClass() {
return classType;
}
@Override
public int[] sqlTypes() {
return SQL_TYPES;
}
}
然后我有：
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager"
class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitName" value="persistenceUnit" />
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="it.oandsi" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
</property>
<property name="jpaProperties">
<props>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
</props>
</property>
</bean>
其中hibernate.dialect是org.hibernate.dialect.MySQL5InnoDBDialect
当我启动tomcat时，我收到错误＆＃34; org.hibernate.MappingException：没有JDBC类型的Dialect映射：2000＆＃34;
这里的堆栈跟踪：
Caused by: org.hibernate.MappingException: No Dialect mapping for JDBC type: 2000
at org.hibernate.dialect.TypeNames.get(TypeNames.java:70)
at org.hibernate.dialect.TypeNames.get(TypeNames.java:101)
at org.hibernate.dialect.Dialect.getTypeName(Dialect.java:346)
at org.hibernate.mapping.Column.getSqlType(Column.java:231)
at org.hibernate.mapping.Table.sqlAlterStrings(Table.java:473)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.migrateTable(AbstractSchemaMigrator.java:295)
at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:75)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:203)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:110)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:183)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:309)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:452)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:889)
拜托，你能帮助我吗？
答案 0 :(得分：1)
您需要扩展MySQL5InnoDBDialect方言并提供映射。它是如此简单（前提是您已经配置了usertype和其他已配置）作为将以下构造函数添加到自定义类。
public MyCustomDialect() {
super();
this.registerColumnType(Types.JAVA_OBJECT, "json"); // JAVA_OBJECT = 2000
}