用过hibernate的人都知道,有时我们要用数据库的视图。但关键是视图没有主键,这个用Myeclipse自动生成的POJO类就有两个。一个类名.java,一个是类名Id.java,而映射文件只有一个。这样你不能直接用Hibernate的“from类名”,只有用“select 类名.id. 属性名from类名”,因为只要视图中有一个字段有一个为NULL,你查出来的数据就会为NULL.而用后者这样查出来的对象是一个Object对象。Object对象不好拆分。不能直接用“类名.属性名”。其实我们可以强制修改 类名.hgc.xml .
例如:
我们有这样一个视图
public class AllTablePb implements Serializable { // Fields private AllTablePbId id; // Property accessors public AllTablePbId getId() { return this.id; } public void setId(AllTablePbId id) { this.id = id; } } public class AllTablePbId implements java.io.Serializable { // Fields private String owner; private String tableName; private String columnName; private String dataType; private String pbcCnam; private String pbcCmnt; // Property accessors public String getOwner() { return this.owner; } public void setOwner(String owner) { this.owner = owner; } public String getTableName() { return this.tableName; } public void setTableName(String tableName) { this.tableName = tableName; } public String getColumnName() { return this.columnName; } public void setColumnName(String columnName) { this.columnName = columnName; } public String getDataType() { return this.dataType; } public void setDataType(String dataType) { this.dataType = dataType; } public String getPbcCnam() { return this.pbcCnam; } public void setPbcCnam(String pbcCnam) { this.pbcCnam = pbcCnam; } public String getPbcCmnt() { return this.pbcCmnt; } public void setPbcCmnt(String pbcCmnt) { this.pbcCmnt = pbcCmnt; } }
配置文件:
<hibernate-mapping> <class name="com.hhkj.workflow.bean.AllTablePb" table="V_ALLTAB_PB" schema="CANP"> <composite-id name="id" class="com.hhkj.workflow.bean.AllTablePbId"> <key-property name="owner" type="string"> <column name="OWNER" length="30" /> </key-property> <key-property name="tableName" type="string"> <column name="TABLE_NAME" length="30" /> </key-property> <key-property name="columnName" type="string"> <column name="COLUMN_NAME" length="30" /> </key-property> <key-property name="dataType" type="string"> <column name="DATA_TYPE" length="106" /> </key-property> <key-property name="pbcCnam" type="string"> <column name="PBC_CNAM" length="30" /> </key-property> <key-property name="pbcCmnt" type="string"> <column name="PBC_CMNT" length="254" /> </key-property> </composite-id> </class> </hibernate-mapping>
而如何把联合主键转换为普通的主键呢。那我就就把AllTablePb删除。把AllTablePbId改为AllTablePb。
配置文件改为:
<hibernate-mapping> <class name="com.hhkj.workflow.bean.AllTablePb" table="V_ALLTAB_PB" schema="CANP"> <id name="owner" type="string"> <column name="OWNER" length="30" /> </id> <property name="tableName" type="string"> <column name="TABLE_NAME" length="30" /> </property> <property name="columnName" type="string"> <column name="COLUMN_NAME" length="30" /> </property> <property name="dataType" type="string"> <column name="DATA_TYPE" length="106" /> </property> <property name="pbcCnam" type="string"> <column name="PBC_CNAM" length="30" /> </property> <property name="pbcCmnt" type="string"> <column name="PBC_CMNT" length="254" /> </property> </class> </hibernate-mapping>
对于配置文件的新主键是任意的。