準備先把以前寫的持久層及表示層框架寫完再寫loonframework-game包(實際上是想自己業余建站用，用現成的框架太無聊，重復發明輪子的最大意義就在于解悶……)，在2005年時寫過一個開頭，由于自己沒有整理文檔，現在拿起來就覺得代碼很亂，又懶于寫文檔，于是把一些心得類的東西整理一下，用以備忘。
在此持久層框架中，我將持久化過程分為兩個松耦合模塊，第一模塊封裝jdbc操作，隱藏Connection及相關事務，處理driver差異后執行標準CRUD并釋放資源，于第二模塊進行實體映射操作。
但和Spring JdbcTemplate等jdbc封裝略有不同的是，我除了直接將結果集轉為List和實體返回外，還引入了一個類似CachedRowSet但非繼承CachedRowSet或ResultSet的結果集cache實體（沒有提供諸如CachedRowSet的execute功能，原因大家都知道……PS:05年我用Hibernate還比較少，現在看來和Hierbante的ScrollableResults接口超級類似，頗感java技術殊途同歸|||）。
但在此類get數據時，由于我將所有ResultSet數據無差別以object方式存儲，當object為二進制對象時，為實現blob和clob接口就需要進行數據轉換，將二進制對象轉為blob或clob實現，為此完成代碼如下。
比較hibernate的blobimpl而言（hibernate的blobimpl只有getBinaryStream()實現，因為別的對它也沒用……），實現了更多的函數以供調用。
BlobImpl.java
package org.loon.framework.dao.lob;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.SQLException;
import org.loon.framework.Loon;
import org.loon.framework.helper.FileHelper;
/**
* <p>
* Title: LoonFramework
* </p>
* <p>
* Description:二進制大對象Blob實現，用于轉化二進制對象為blob實例，只提供get部分方法(雖然象征性的寫了
* set實現，但沒有對數據庫進行操作，只是擺設……).
* </p>
* <p>
* Copyright: Copyright (c) 2007
* </p>
* <p>
* Company: LoonFramework
* </p>
* <p>
* License: http://www.apache.org/licenses/LICENSE-2.0
* </p>
*
* @author chenpeng
* @email：ceponline@yahoo.com.cn
* @version 0.1
*/
public class BlobImpl implements Blob {
private byte[] _bytes = new byte[0];
private int _length = 0;
/**
* 構造函數，以byte[]構建blob
*
* @param bytes
*/
public BlobImpl(byte[] bytes) {
init(bytes);
}
/**
* 構造函數，以InputStream構建blob
*
* @param bytes
*/
public BlobImpl(InputStream input) {
init(FileHelper.read(input));
}
/**
* 構造函數，以blob重新構建blob
*
* @param bytes
*/
public BlobImpl(Blob blob) {
init(blobToBytes(blob));
}
/**
* 初始化byte[]
*
* @param b
*/
private void init(byte[] bytes) {
_bytes = bytes;
_length = _bytes.length;
}
/**
* 將blob轉為byte[]
*
* @param blob
* @return
*/
private byte[] blobToBytes(Blob blob) {
BufferedInputStream is = null;
try {
is = new BufferedInputStream(blob.getBinaryStream());
byte[] bytes = new byte[(int) blob.length()];
int len = bytes.length;
int offset = 0;
int read = 0;
while (offset < len
&& (read = is.read(bytes, offset, len - offset)) >= 0) {
offset += read;
}
return bytes;
} catch (Exception e) {
return null;
} finally {
try {
is.close();
is = null;
} catch (IOException e) {
return null;
}
}
}
/**
* 獲得blob中數據實際長度
*
* @return
* @throws SQLException
*/
public long length() throws SQLException {
return _bytes.length;
}
/**
* 返回指定長度的byte[]
*
* @param pos
* @param len
* @return
* @throws SQLException
*/
public byte[] getBytes(long pos, int len) throws SQLException {
if (pos == 0 && len == length())
return _bytes;
try {
byte[] newbytes = new byte[len];
System.arraycopy(_bytes, (int) pos, newbytes, 0, len);
return newbytes;
} catch (Exception e) {
throw new SQLException("Inoperable scope of this array");
}
}
/**
* 返回InputStream
*
* @return
* @throws SQLException
*/
public InputStream getBinaryStream() throws SQLException {
return new ByteArrayInputStream(_bytes);
}
/**
* 獲取此byte[]中start的字節位置
*
* @param pattern
* @param start
* @return
* @throws SQLException
*/
public long position(byte[] pattern, long start) throws SQLException {
start--;
if (start < 0) {
throw new SQLException("start < 0");
}
if (start >= _length) {
throw new SQLException("start >= max length");
}
if (pattern == null) {
throw new SQLException("pattern == null");
}
if (pattern.length == 0 || _length == 0 || pattern.length > _length) {
return -1;
}
int limit = (int) _length - pattern.length;
for (int i = (int) start; i <= limit; i++) {
int p;
for (p = 0; p < pattern.length && _bytes[i + p] == pattern[p]; p++) {
if (p == pattern.length) {
return i + 1;
}
}
}
return -1;
}
/**
* 獲取指定的blob中start的字節位置
*
* @param pattern
* @param start
* @return
* @throws SQLException
*/
public long position(Blob pattern, long start) throws SQLException {
return position(blobToBytes(pattern), start);
}
/**
* 不支持操作異常拋出
*
*/
void nonsupport() {
throw new UnsupportedOperationException("This method is not supported！");
}
/**
* 釋放Blob對象資源
*
* @throws SQLException
*/
public void free() throws SQLException {
_bytes = new byte[0];
_length = 0;
}
/**
* 返回指定長度部分的InputStream，并返回InputStream
*
* @param pos
* @param len
* @return
* @throws SQLException
*/
public InputStream getBinaryStream(long pos, long len) throws SQLException {
return new ByteArrayInputStream(getBytes(pos, (int) len));
}
/**
* 以指定指定長度將二進制流寫入OutputStream，并返回OutputStream
*
* @param pos
* @return
* @throws SQLException
*/
public OutputStream setBinaryStream(long pos) throws SQLException {
// 暫不支持
nonsupport();
pos--;
if (pos < 0) {
throw new SQLException("pos < 0");
}
if (pos > _length) {
throw new SQLException("pos > length");
}
// 將byte[]轉為ByteArrayInputStream
ByteArrayInputStream inputStream = new ByteArrayInputStream(_bytes);
ByteArrayOutputStream os = new ByteArrayOutputStream();
byte[] bytes = new byte[(int) pos];
try {
bytes = new byte[inputStream.available()];
int read;
while ((read = inputStream.read(bytes)) >= 0) {
os.write(bytes, 0, read);
}
} catch (IOException e) {
e.getStackTrace();
}
// 返回OutputStream
return (OutputStream) os;
}
/**
* 設定byte[]
*
* @param pos
* @param bytes
* @param offset
* @param size
* @param copy
* @return
* @throws SQLException
*/
private int setBytes(long pos, byte[] bytes, int offset, int size,
boolean copy) throws SQLException {
// 暫不支持
nonsupport();
pos--;
if (pos < 0) {
throw new SQLException("pos < 0");
}
if (pos > _length) {
throw new SQLException("pos > max length");
}
if (bytes == null) {
throw new SQLException("bytes == null");
}
if (offset < 0 || offset > bytes.length) {
throw new SQLException("offset < 0 || offset > bytes.length");
}
if (size < 0 || pos + size > (long) Integer.MAX_VALUE
|| offset + size > bytes.length) {
throw new SQLException();
}
// 當copy數據時
if (copy) {
_bytes = new byte[size];
System.arraycopy(bytes, offset, _bytes, 0, size);
} else { // 否則直接替換對象
_bytes = bytes;
}
return _bytes.length;
}
/**
* 設定指定開始位置byte[]
*
* @param pos
* @param bytes
* @return
* @throws SQLException
*/
public int setBytes(long pos, byte[] bytes) throws SQLException {
// 暫不支持
nonsupport();
return setBytes(pos, bytes, 0, bytes.length, true);
}
/**
* 設定byte[]
*
* @param pos
* @param bytes
* @param offset
* @param len
* @return
* @throws SQLException
*/
public int setBytes(long pos, byte[] bytes, int offset, int len)
throws SQLException {
// 暫不支持
nonsupport();
return setBytes(pos, bytes, offset, len, true);
}
/**
* 截取相應部分數據
*
* @param len
* @throws SQLException
*/
public void truncate(long len) throws SQLException {
if (len < 0) {
throw new SQLException("len < 0");
}
if (len > _length) {
throw new SQLException("len > max length");
}
_length = (int) len;
}
public static void main(String[] args) {
//獲得一個指定文件的blob
//PS:天地良心啊，沒抄襲hibernate寫法，無奈的寫一樣了，不過比他多實現了點方法……（還特意把函數改名，不然更像|||）……
Blob blob = Loon.makeBlob("D:/test.txt");
// 以byte[]獲得blob實例
//Blob blob = new BlobImpl(bytes);
try {
// getBytes測試
// 取出0到blob結束范圍的byte[]
byte[] buffer = blob.getBytes(0, (int) blob.length());
// 以gb2312編碼將byte[]轉為string顯示
System.out.println(new String(buffer, "gb2312"));
// getBinaryStream測試
BufferedInputStream is = new BufferedInputStream(blob
.getBinaryStream());
buffer = new byte[(int) blob.length()];
int len = buffer.length;
int offset = 0;
int read = 0;
while (offset < len
&& (read = is.read(buffer, offset, len - offset)) >= 0) {
offset += read;
}
System.out.println(new String(buffer, "gb2312"));
// getBinaryStream范圍取值測試,取0to4的byte[]
is = new BufferedInputStream(blob.getBinaryStream(0, 4));
//將is轉為byte[]后轉為String顯示
System.out.println(FileHelper.readToString(is, "gb2312"));
} catch (Exception e) {
e.printStackTrace();
}
}
}
在此持久層框架中，我將持久化過程分為兩個松耦合模塊，第一模塊封裝jdbc操作，隱藏Connection及相關事務，處理driver差異后執行標準CRUD并釋放資源，于第二模塊進行實體映射操作。
但和Spring JdbcTemplate等jdbc封裝略有不同的是，我除了直接將結果集轉為List和實體返回外，還引入了一個類似CachedRowSet但非繼承CachedRowSet或ResultSet的結果集cache實體（沒有提供諸如CachedRowSet的execute功能，原因大家都知道……PS:05年我用Hibernate還比較少，現在看來和Hierbante的ScrollableResults接口超級類似，頗感java技術殊途同歸|||）。
但在此類get數據時，由于我將所有ResultSet數據無差別以object方式存儲，當object為二進制對象時，為實現blob和clob接口就需要進行數據轉換，將二進制對象轉為blob或clob實現，為此完成代碼如下。
比較hibernate的blobimpl而言（hibernate的blobimpl只有getBinaryStream()實現，因為別的對它也沒用……），實現了更多的函數以供調用。
BlobImpl.java
package org.loon.framework.dao.lob;import java.io.BufferedInputStream;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.sql.Blob;import java.sql.SQLException;import org.loon.framework.Loon;import org.loon.framework.helper.FileHelper;/**
* <p> * Title: LoonFramework * </p> * <p> * Description:二進制大對象Blob實現，用于轉化二進制對象為blob實例，只提供get部分方法(雖然象征性的寫了 * set實現，但沒有對數據庫進行操作，只是擺設……). * </p> * <p> * Copyright: Copyright (c) 2007 * </p> * <p> * Company: LoonFramework * </p> * <p> * License: http://www.apache.org/licenses/LICENSE-2.0 * </p> * * @author chenpeng * @email：ceponline@yahoo.com.cn * @version 0.1 */public class BlobImpl implements Blob { private byte[] _bytes = new byte[0]; private int _length = 0; /**
* 構造函數，以byte[]構建blob * * @param bytes */ public BlobImpl(byte[] bytes) { init(bytes); } /** * 構造函數，以InputStream構建blob * * @param bytes */ public BlobImpl(InputStream input) { init(FileHelper.read(input)); } /** * 構造函數，以blob重新構建blob * * @param bytes */ public BlobImpl(Blob blob) { init(blobToBytes(blob)); } /** * 初始化byte[] * * @param b */ private void init(byte[] bytes) { _bytes = bytes; _length = _bytes.length; } /** * 將blob轉為byte[] * * @param blob * @return */ private byte[] blobToBytes(Blob blob) { BufferedInputStream is = null; try { is = new BufferedInputStream(blob.getBinaryStream()); byte[] bytes = new byte[(int) blob.length()]; int len = bytes.length; int offset = 0; int read = 0; while (offset < len && (read = is.read(bytes, offset, len - offset)) >= 0) { offset += read; } return bytes; } catch (Exception e) { return null; } finally { try { is.close(); is = null; } catch (IOException e) { return null; } } } /** * 獲得blob中數據實際長度 * * @return * @throws SQLException */ public long length() throws SQLException { return _bytes.length; } /** * 返回指定長度的byte[] * * @param pos * @param len * @return * @throws SQLException */ public byte[] getBytes(long pos, int len) throws SQLException { if (pos == 0 && len == length()) return _bytes; try { byte[] newbytes = new byte[len]; System.arraycopy(_bytes, (int) pos, newbytes, 0, len); return newbytes; } catch (Exception e) { throw new SQLException("Inoperable scope of this array"); } } /** * 返回InputStream * * @return * @throws SQLException */ public InputStream getBinaryStream() throws SQLException { return new ByteArrayInputStream(_bytes); } /** * 獲取此byte[]中start的字節位置 * * @param pattern * @param start * @return * @throws SQLException */ public long position(byte[] pattern, long start) throws SQLException { start--; if (start < 0) { throw new SQLException("start < 0"); } if (start >= _length) { throw new SQLException("start >= max length"); } if (pattern == null) { throw new SQLException("pattern == null"); } if (pattern.length == 0 || _length == 0 || pattern.length > _length) { return -1; } int limit = (int) _length - pattern.length; for (int i = (int) start; i <= limit; i++) { int p; for (p = 0; p < pattern.length && _bytes[i + p] == pattern[p]; p++) { if (p == pattern.length) { return i + 1; } } } return -1; } /** * 獲取指定的blob中start的字節位置 * * @param pattern * @param start * @return * @throws SQLException */ public long position(Blob pattern, long start) throws SQLException { return position(blobToBytes(pattern), start); } /** * 不支持操作異常拋出 * */ void nonsupport() { throw new UnsupportedOperationException("This method is not supported！"); } /** * 釋放Blob對象資源 * * @throws SQLException */ public void free() throws SQLException { _bytes = new byte[0]; _length = 0; } /** * 返回指定長度部分的InputStream，并返回InputStream * * @param pos * @param len * @return * @throws SQLException */ public InputStream getBinaryStream(long pos, long len) throws SQLException { return new ByteArrayInputStream(getBytes(pos, (int) len)); } /** * 以指定指定長度將二進制流寫入OutputStream，并返回OutputStream * * @param pos * @return * @throws SQLException */ public OutputStream setBinaryStream(long pos) throws SQLException { // 暫不支持 nonsupport(); pos--; if (pos < 0) { throw new SQLException("pos < 0"); } if (pos > _length) { throw new SQLException("pos > length"); } // 將byte[]轉為ByteArrayInputStream ByteArrayInputStream inputStream = new ByteArrayInputStream(_bytes); ByteArrayOutputStream os = new ByteArrayOutputStream(); byte[] bytes = new byte[(int) pos]; try { bytes = new byte[inputStream.available()]; int read; while ((read = inputStream.read(bytes)) >= 0) { os.write(bytes, 0, read); } } catch (IOException e) { e.getStackTrace(); } // 返回OutputStream return (OutputStream) os; } /** * 設定byte[] * * @param pos * @param bytes * @param offset * @param size * @param copy * @return * @throws SQLException */ private int setBytes(long pos, byte[] bytes, int offset, int size, boolean copy) throws SQLException { // 暫不支持 nonsupport(); pos--; if (pos < 0) { throw new SQLException("pos < 0"); } if (pos > _length) { throw new SQLException("pos > max length"); } if (bytes == null) { throw new SQLException("bytes == null"); } if (offset < 0 || offset > bytes.length) { throw new SQLException("offset < 0 || offset > bytes.length"); } if (size < 0 || pos + size > (long) Integer.MAX_VALUE || offset + size > bytes.length) { throw new SQLException(); } // 當copy數據時 if (copy) { _bytes = new byte[size]; System.arraycopy(bytes, offset, _bytes, 0, size); } else { // 否則直接替換對象 _bytes = bytes; } return _bytes.length; } /** * 設定指定開始位置byte[] * * @param pos * @param bytes * @return * @throws SQLException */ public int setBytes(long pos, byte[] bytes) throws SQLException { // 暫不支持 nonsupport(); return setBytes(pos, bytes, 0, bytes.length, true); } /** * 設定byte[] * * @param pos * @param bytes * @param offset * @param len * @return * @throws SQLException */ public int setBytes(long pos, byte[] bytes, int offset, int len) throws SQLException { // 暫不支持 nonsupport(); return setBytes(pos, bytes, offset, len, true); } /** * 截取相應部分數據 * * @param len * @throws SQLException */ public void truncate(long len) throws SQLException { if (len < 0) { throw new SQLException("len < 0"); } if (len > _length) { throw new SQLException("len > max length"); } _length = (int) len; } public static void main(String[] args) { //獲得一個指定文件的blob //PS:天地良心啊，沒抄襲hibernate寫法，無奈的寫一樣了，不過比他多實現了點方法……（還特意把函數改名，不然更像|||）…… Blob blob = Loon.makeBlob("D:/test.txt"); // 以byte[]獲得blob實例 //Blob blob = new BlobImpl(bytes); try { // getBytes測試 // 取出0到blob結束范圍的byte[] byte[] buffer = blob.getBytes(0, (int) blob.length()); // 以gb2312編碼將byte[]轉為string顯示 System.out.println(new String(buffer, "gb2312")); // getBinaryStream測試 BufferedInputStream is = new BufferedInputStream(blob .getBinaryStream()); buffer = new byte[(int) blob.length()]; int len = buffer.length; int offset = 0; int read = 0; while (offset < len && (read = is.read(buffer, offset, len - offset)) >= 0) { offset += read; } System.out.println(new String(buffer, "gb2312")); // getBinaryStream范圍取值測試,取0to4的byte[] is = new BufferedInputStream(blob.getBinaryStream(0, 4)); //將is轉為byte[]后轉為String顯示 System.out.println(FileHelper.readToString(is, "gb2312")); } catch (Exception e) { e.printStackTrace(); } }}
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