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http断点续传简单实现(java)

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/* U>.5vK.+  
**SiteFileFetch.java ]S@T|08b  
*/ ftPhE)i  
package NetFox; ^lZ7%6  
import java.io.*; pKj:)6t"  
import java.net.*; ip}%Y6Wj  
h?OSmzRLd  
biS[GyQ  
public class SiteFileFetch extends Thread { /<$|tp\Rc  
_RxnB?  
fS|e{!iI"  
SiteInfoBean siteInfoBean = null; //文件信息Bean dJnKa]X  
long[] nStartPos; //开始位置 ~aQR_S  
long[] nEndPos; //结束位置 C6a-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |zP~/  
long nFileLength; //文件长度 \#w8~+`Gq  
boolean bFirst = true; //是否第一次取文件 c7@/<*E+  
boolean bStop = false; //停止标志 kv2o.q  
File tmpFile; //文件下载的临时信息 {fl[BX]kZ  
DataOutputStream output; //输出到文件的输出流 LK*9`dzv=G  
`fX\pOk~e  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) y_q1Y70i2r  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;R2A>f~  
{ h>[ qXz  
siteInfoBean = bean; z(^dwMw}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .6 0yQ[aE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L[*cbjt[  
if(tmpFile.exists ()) {c LWum[SY  
{ a`^$xOK,  
bFirst = false; R_GA`U\ {  
read_nPos(); 1EQ:@1  
} <zvtQ^{]  
else UukY9n];]  
{ v< 2,OcH  
nStartPos = new long[bean.getNSplitter()]; V?x&\<;,  
nEndPos = new long[bean.getNSplitter()]; |4j6}g\  
} 9IG<9uj  
(0LA.aBIf  
'sa)_?Hy  
#Y-_kQV*  
} *)^ ZUk  
d$+0 ;D4E  
{ 6qxg_{  
public void run() :PY8)39@K  
{ 9 4lt?|3=  
//获得文件长度  (yd(ZY  
//分割文件 @zi0:3`#0\  
//实例FileSplitterFetch pG)dF@  
//启动FileSplitterFetch线程 h]z8.k2n  
//等待子线程返回 ZTfW_0   
try{ gYGoJH1  
if(bFirst) z4(\yx  
{ Yqo@ g2g  
nFileLength = getFileSize(); r<srTHGL o  
if(nFileLength == -1) ^*$!9~  
{ IV':sNV  
System.err.println("File Length is not known!"); ~.U \Y  
} hH;i_("i(h  
else if(nFileLength == -2) f]?&R c2C  
{ 06.8m;{N  
System.err.println("File is not access!"); w^nA/=;r  
} `VGw5o  
else Th\T$T`X$  
{ [U^Cz{G  
for(int i=0;i<nStartPos.length;i++)  g;AW  
{ d*k5h<jM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Rb:?%\=  
} knV*,   
for(int i=0;i<nEndPos.length-1;i++) oVbs^sbRH  
{ A(`Mwh+  
nEndPos = nStartPos[i+1];  #X$s5H  
} ls9Y?  
nEndPos[nEndPos.length-1] = nFileLength; y<R5}F  
} Da6l =M  
} #FRm<9/j  
B]gyj  
W)  
//启动子线程 X#ha*u~U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7AGUi+!ICl  
for(int i=0;i<nStartPos.length;i++) wEI? 9  
{ bv hV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !e |Bi{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |<oqT+?i  
nStartPos,nEndPos,i); x.|sCqx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c0&! S-4M  
fileSplitterFetch.start(); d >zC[]1  
} ""N~##)8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0/7.RpX,.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u` (yT<>H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $*_79F2zN  
nEndPos = " + nFileLength); Ks(l :oUB  
// fileSplitterFetch[nPos.length-1].start(); gy|o#&e]%  
s)-bOZi  
7u :kR;wk  
//等待子线程结束 0xCe6{86  
//int count = 0; tr/.pw6  
//是否结束while循环 ?GLCd7TP  
boolean breakWhile = false; ph!h8@e  
3tUn?; 9B  
5K$<Ad4$b  
while(!bStop) <W7WlT  
{ Uy)pEEu  
write_nPos(); (47la$CR  
Utility.sleep(500); jMS>B)'TO  
breakWhile = true; ('dbMH\O  
Tl]yl$  
w6Mv%ZO_  
for(int i=0;i<nStartPos.length;i++) TMs Cl6dB  
{ G6x'Myg I  
if(!fileSplitterFetch.bDownOver) itiSZL,  
{ |_+l D|'  
breakWhile = false; :1gpbfW  
break; #a tL2(wJ  
} )_o^d>$da  
} 4N7|LxNNl_  
if(breakWhile) ; }ThBb3  
break; z" ?WT$  
 ]EQ*!  
o :4#Ak S  
//count++; _E6N*ORV  
//if(count>4) zq?xY`E  
// siteStop(); 8$ X3J[_j  
} /?TR_>  
;AL:V U  
Q~' \oWz  
System.err.println("文件下载结束!"); 2!b##`UjA7  
} `Nz`5}8.?  
catch(Exception e){e.printStackTrace ();} .XkVdaX  
} 4mX?PKvbn  
I};*O6D`  
QJjk#*?,|  
//获得文件长度 "d}ey=$h4  
public long getFileSize() Co=Bq{GY  
{ u'DpZ  
int nFileLength = -1; 8=0I4\  
try{ :LdPqFXj  
URL url = new URL(siteInfoBean.getSSiteURL()); c"1Z,M;G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x1E;dbOZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0XqxW\8_l  
pNmWBp|ER  
Xi\c>eALO  
int responseCode=httpConnection.getResponseCode(); =WZ@{z9J  
if(responseCode>=400) n:1Ijh 1  
{ e VQ-?DK  
processErrorCode(responseCode); }*qj,8-9  
return -2; //-2 represent access is error pDvznpQ  
} AA=eWg  
Y"m(hs $  
91q  
String sHeader; HGd.meQ  
0plX"NU  
F>X<=YO0  
for(int i=1;;i++) kh#fUAt  
{ fl2XI=[v4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y ZuA"l Y  
//Utility.log(in.readLine()); N|Xm{@C  
sHeader=httpConnection.getHeaderFieldKey(i); H5:f&m  
if(sHeader!=null) k6o8'6wN  
{ SQx&4R.  
if(sHeader.equals("Content-Length")) "Y- WY,H  
{ qn |~YXn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cKoW5e|u  
break; @tD (<*f+  
} 5nsoWqnE8  
} >&7^yXS  
else ?`O^;f  
break; S QGYH  
} Un T\6u  
} r=54@`O!  
catch(IOException e){e.printStackTrace ();} SR?(z  
catch(Exception e){e.printStackTrace ();} %&V%=-O_7  
S)4p'cUwq  
HTvUt*U1  
Utility.log(nFileLength); _)~VKA]""  
?~yJ7~3TS<  
5wl;fL~e  
return nFileLength; *-Vr=e<8   
} %yk_(3a  
o[+t}hC[  
wArfnB&  
//保存下载信息(文件指针位置) 6f ?,v5  
private void write_nPos() . sFN[>)  
{ IvI..#EzG  
try{ 4fjwC,,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X:g#&e_  
output.writeInt(nStartPos.length); 'V&Uh]>  
for(int i=0;i<nStartPos.length;i++) x',6VTz^  
{ &`tAQN*Z  
// output.writeLong(nPos); 4udj"-V  
output.writeLong(fileSplitterFetch.nStartPos); S'hUh'PZ  
output.writeLong(fileSplitterFetch.nEndPos); *yjnC  
} 0'YP9-C3  
output.close(); n5^57[(  
} ~<s =yjTu+  
catch(IOException e){e.printStackTrace ();} oDi+\0  
catch(Exception e){e.printStackTrace ();} Qh-:P`CN  
} WY!4^<|w"  
f#w u~*c  
Z,Us<du  
//读取保存的下载信息(文件指针位置) WjM7s]ZRv  
private void read_nPos() (+/d*4  
{ NuD|%Ebs  
try{ MxKTKBxQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]yZ%wU9!  
int nCount = input.readInt(); *)6\ V}`  
nStartPos = new long[nCount]; ;^E_BJm  
nEndPos = new long[nCount]; pIYXYQ=Z  
for(int i=0;i<nStartPos.length;i++) .uxM&|0H  
{ aJA(UN45  
nStartPos = input.readLong(); R<{Vgy  
nEndPos = input.readLong(); ;z N1Qb  
} +{I" e,Nk  
input.close(); %%>nM'4<  
} $AE5n>ZD$  
catch(IOException e){e.printStackTrace ();} b(Tvc  
catch(Exception e){e.printStackTrace ();} (j??  
} M6Np!0G  
e"NP]_vh,  
#Nco|v  
private void processErrorCode(int nErrorCode) C"_ Roir?  
{ h0g?=hJq  
System.err.println("Error Code : " + nErrorCode); /S1/ZI  
} Qx8(w"k*  
CS(2bj^6 D  
p:W]  
//停止文件下载 .jk A'i@  
public void siteStop() ;+6><O!G  
{ &);P|v`8  
bStop = true; kV4Oq.E  
for(int i=0;i<nStartPos.length;i++) 3JBXGT0gJ  
fileSplitterFetch.splitterStop(); 6ST(=X_C  
jY]51B  
Gsb^gd  
} N)R5#JX  
} *L$_80  
//负责部分文件的抓取 fF r9]  
**FileSplitterFetch.java k{N!}%*2  
*/ NX.5 u8Pf  
package NetFox; .8!\6=iJB  
v:yU+s|kN  
A1,q 3<<D%  
import java.io.*; 0BhcXH t  
import java.net.*; %DXBl:!Y`  
A8Fe@$<#8  
Vd  d  
public class FileSplitterFetch extends Thread { HK~SD:d  
BI%XF 9{  
#u8#< ,w  
String sURL; //File URL 9q_{_%G%  
long nStartPos; //File Snippet Start Position =W:=}ODD  
long nEndPos; //File Snippet End Position ?6`B;_m  
int nThreadID; //Thread's ID kROIVO1|`  
boolean bDownOver = false; //Downing is over mTxqcQc:7  
boolean bStop = false; //Stop identical N!3Tg564j  
FileAccessI fileAccessI = null; //File Access interface z8JW iRn  
F@f4-NR>  
 -D'XxOI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Bdb}4X rL  
{ JcmJq fR  
this.sURL = sURL; >V27#L2:J  
this.nStartPos = nStart; NjOUe?BQ  
this.nEndPos = nEnd;  QSY>8P  
nThreadID = id; yV\%K6d|3&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @*Ry`)T  
} HdB>CVuh  
4\ Xaou2V[  
Z/ jmi  
public void run() 5:f!EMb  
{ Zp~yemERr  
while(nStartPos < nEndPos && !bStop) 'g,h  
{ L-D4>+  
rlY0UA,  
_O uNX.yrG  
try{ 86Q3d%;-yo  
URL url = new URL(sURL); aXJ/"k #Tl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e7xBi!I)~  
httpConnection.setRequestProperty("User-Agent","NetFox"); N\g=9o|Q  
String sProperty = "bytes="+nStartPos+"-"; !uW*~u  
httpConnection.setRequestProperty("RANGE",sProperty); |yeQz  
Utility.log(sProperty); Dn 0L%?_   
6Uk+a=Ar  
"}*D,[C5e  
InputStream input = httpConnection.getInputStream(); /u4RZ|&as  
//logResponseHead(httpConnection); 'A7!@hVy  
hoqZb<:  
9>S)*lU&s  
byte[] b = new byte[1024]; CMW4Zqau*  
int nRead; ~. vridH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yT@Aj;X0v  
{ QTi@yT:  
nStartPos += fileAccessI.write(b,0,nRead); EOrui:.B)  
//if(nThreadID == 1) rtJER?A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y|fD)zG_  
} w_Slg&S  
)0exGx+:  
-|#{V.G3'  
Utility.log("Thread " + nThreadID + " is over!"); v-3VzAd=*&  
bDownOver = true; K_)~&Cu*'  
//nPos = fileAccessI.write (b,0,nRead); qs ep9z.  
} VRQ`-#  
catch(Exception e){e.printStackTrace ();} c.IUqin  
} znsQ/[  
} w8 :[w  
%%s)D4sW  
9efey? z  
//打印回应的头信息 S9Yzvq!(  
public void logResponseHead(HttpURLConnection con) 3d6z_Yd:  
{ Gc`PO  
for(int i=1;;i++) H@ 1'El\9  
{ $kTm"I  
String header=con.getHeaderFieldKey(i); x:MwM?  
if(header!=null) s"=TM$Vb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8c)GUx  
Utility.log(header+" : "+con.getHeaderField(header)); Q /4-7  
else t[`LG)  
break; {S{%KkAV  
} rzAf  {2  
} m1pA]}Y/5o  
@-dGZ 5  
9m)$^U>oz  
public void splitterStop() Hp=BnN  
{ -a)1L'R  
bStop = true; A r]*?:4y[  
} KSchgon0V  
qKfUm:7Q_  
h$'6."I  
} %@Gy<t,  
zX_F+"]THt  
spfW)v/T!  
/* metn&  
**FileAccess.java vYV!8o.I  
*//文件访问(定位,写) uAA2G\3  
package NetFox; @@o J@;  
import java.io.*; x*vD^1"'P  
$UH:r  
DH?n~qKpC  
public class FileAccessI implements Serializable{ &6vaLx  
nKm# kb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7?whxi Qs  
RandomAccessFile oSavedFile; 5VTVx1P[8  
long nPos; a -Pz<*  
Ljm`KE\Q;t  
)\Q(=:  
public FileAccessI() throws IOException Pb'(Y  
{ x;7l>uR  
this("",0); ck{S  
} }?,?2U,8:  
Q^f{H.  
xkDK5&V  
public FileAccessI(String sName,long nPos) throws IOException \PxT47[@e  
{ N=\ zx^w,  
oSavedFile = new RandomAccessFile(sName,"rw"); _s5^\~ao  
this.nPos = nPos; H}kZ;8  
oSavedFile.seek(nPos); (s;W>,~q  
} U~][ ph  
Wm6qy6HR  
d78 [(;  
public synchronized int write(byte[] b,int nStart,int nLen) ?-)!dl%N  
{ k 3m_L-  
int n = -1; [=(8yUV'G  
try{ l9f_NJHo  
oSavedFile.write(b,nStart,nLen); ~-zIB=TyK  
n = nLen; ,N(Yjq"R  
} e El)wZ,A  
catch(IOException e) $,~Ily7w  
{ ;-VZVp}Y  
e.printStackTrace (); r"2lcNE  
} X=#us7W}  
_ACN  
&NBH'Rt  
return n; BEaF-*?A  
} @??3d9I  
ar<8wq<4G  
CKn2ZL  
} _dm0*T ?  
&qS%~h%2  
u$R5Q{H_  
/* m*]`/:/X[  
**SiteInfoBean.java i=#`7pt%'a  
*/ E\!X$  
package NetFox; \~*<[.8~  
<{cY2cx~3  
6 ^3RfF^W  
public class SiteInfoBean { o`c+eMwr(  
~Tt@ v`}  
 C^"zU>W_  
private String sSiteURL; //Site's URL eY :"\c3  
private String sFilePath; //Saved File's Path CnB[ImMs(A  
private String sFileName; //Saved File's Name h}@wPP{  
private int nSplitter; //Count of Splited Downloading File YjDQ`f/  
gF p3=s0~  
{ze69 h  
public SiteInfoBean() a5#G48'X  
{//nSplitter的缺省值为5 X\Bl? F   
//default value of nSplitter is 5 .h meP MK  
this("","","",5); Ts !g=F  
} "6'",  
f8lyH'z0 @  
$Lj ]NtO  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <u\Hy0g  
{ eP]y\S*P  
sSiteURL= sURL; 7.Y;nem:(  
sFilePath = sPath; HZAT_  
sFileName = sName; 'l^Bb#)"  
this.nSplitter = nSpiltter; t?>}0\1  
-E|"?  
QWOPCoUet  
} 7_ix&oVI  
z)C}}NH*!@  
4u iq'-  
public String getSSiteURL() VF2,(f-*  
{ IRQtA ZV$  
return sSiteURL; i)e6 U(H  
} ,CyX*k8o  
&'/"=lK  
} 9\_s*  
public void setSSiteURL(String value) mvjx &+q  
{ nKGQU,C  
sSiteURL = value; @ 3=pFYW)  
} F[}#7}xjA  
`$ f`55e  
eWDXV-xD  
public String getSFilePath() @}4>:\es  
{ v,}C~L3  
return sFilePath; n0l|7:Mk  
} ?sQg{1"Zr  
nZB ~l=  
Ij(<(y{?Q1  
public void setSFilePath(String value) i[KXkjr  
{ q#3T L<  
sFilePath = value; %J1'>nI!q  
} # QwX|x{  
m[=SCH-;  
W\>O$IX^e  
public String getSFileName() 5L c@=,/0  
{ H"/ J R  
return sFileName; aaU4Jl?L  
} N%f"W&ci  
#-YbZ  
?-c|c_|$  
public void setSFileName(String value) HjK8y@j  
{ q+9^rQ  
sFileName = value; 68?&`/t  
} FBl,Mky  
X>7Pqn'  
b<y*:(:  
public int getNSplitter() 7=N%$]DKZ  
{ $EY[CA E  
return nSplitter; 0\!Bh^++1  
} %BC%fVdP  
 ="]r{  
N>3{!K>/Y:  
public void setNSplitter(int nCount) 3Y#  
{ Q(<A Yu  
nSplitter = nCount; *66EkCj  
} E&J<qTH9  
} k I`HD  
6xx.Z3v  
&5K3AL  
/* m)6 6g]F+  
**Utility.java ^ q ba<#e  
*/ ?&0CEfa?  
package NetFox; H%m^8yW1  
gtH^'vFZ  
8#$HKWUK  
public class Utility { CX/[L)|Ru  
EB&hgz&_  
4'D^>z!c  
public Utility() qWK}  
{ >AV9 K  
Fb<'L5}i  
^kK")+K  
} S".|j$  
xb[yy}>"L  
//线程睡眠 ?W ^`Fa)]o  
public static void sleep(int nSecond) @;9KP6d  
{ NUiv"tAY  
try{ r^.9 |YM5  
Thread.sleep(nSecond); o]p$ w[5  
} o!h::j0,~  
catch(Exception e) w$$pTk|&n  
{ "d/54PKWx  
e.printStackTrace (); "T /$K  
} y+BiaD!U  
} 9*j"@Rm  
)X#$G?|Hn  
//日志 uq6>K/~D  
public static void log(String sMsg) '`}D+IQ(j  
{ sifjmNP  
System.err.println(sMsg); &56\@t^  
} fR;[??NH  
:Hitx  
x s6!NY  
public static void log(int sMsg) S9:ij1  
{ y46sL~HRv  
System.err.println(sMsg); " ?aE3$/  
} W{JR%Sq$  
} |LIcq0Z  
umPN=0u6  
nUq@`G  
/* T^8`ji  
**TestMethod.java 68~]_r.a  
*/ 0@' -g^PS  
package NetFox; # .&t'"u  
9_*3xu<7i  
uuHs)  
public class TestMethod { *W |  
Q.4+"JoG  
{3os9r,  
public TestMethod() $!'Vn)Z7  
{ ///xx/weblogic60b2_win.exe G| &$/]~  
try{ %j0c|u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C.=%8|Zy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }rVLWt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N["M "s(N  
fileFetch.start(); J|V*g]#kP  
} :ldI1*@i<  
catch(Exception e){e.printStackTrace ();} 3KD:JKn^  
sFfargl  
]$)};8;7W  
} 1iqgTi>  
vEt=enQ  
aQWg?,Ju6  
public static void main(String[] args) 5#_GuL%  
{ %MtaWZ  
new TestMethod(); :q1j?0 {2N  
} !k 'E  
} *Q [%r  
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