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http断点续传简单实现(java)

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/* ngeX+@  
**SiteFileFetch.java _j%Rm:m;<  
*/ pxI*vgfN7  
package NetFox; (g7nMrE$j  
import java.io.*; JGj_{|=:  
import java.net.*; <( BAws(X  
YLSG 5vF+  
3qpk Mu3  
public class SiteFileFetch extends Thread { _JR4 PKtx  
hZ2PP ^  
7Mo O2  
SiteInfoBean siteInfoBean = null; //文件信息Bean +QldZba  
long[] nStartPos; //开始位置 {H])Fob  
long[] nEndPos; //结束位置 PDD` eK}Fj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *k+QX   
long nFileLength; //文件长度 A: 0] n  
boolean bFirst = true; //是否第一次取文件 +%U@  
boolean bStop = false; //停止标志 u52; )"&=)  
File tmpFile; //文件下载的临时信息 g-+p(Ll|  
DataOutputStream output; //输出到文件的输出流 N..9N$+(  
Q=^}B}G  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ya:H{#%6  
public SiteFileFetch(SiteInfoBean bean) throws IOException l' "<  
{ Nz!AR$  
siteInfoBean = bean; f{3FoN= z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); TUpEh Q+*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D"^ogY#LK  
if(tmpFile.exists ()) @C z1rKU^l  
{ k;LENB2iv  
bFirst = false; + s[(CI.b  
read_nPos(); /)oxuk&}c  
} DU 8)c$  
else K9w24Oka  
{ +S/8{2%?DG  
nStartPos = new long[bean.getNSplitter()]; V 8n}"  
nEndPos = new long[bean.getNSplitter()]; f_Wn[I{  
} !^8'LMY<I  
#e8CuS  
 K[?wP>s  
FfD2 &(-R  
} 29av8eW?3  
PY>j?otD  
3_33@MM  
public void run() X,y$!2QI  
{ %'g/4I  
//获得文件长度 /OxF5 bN2  
//分割文件 ^eZqsd8a  
//实例FileSplitterFetch jBE= Ij  
//启动FileSplitterFetch线程 7XR[`Tn9<  
//等待子线程返回 P `2Rte6s  
try{ IloHU6h'  
if(bFirst) A@DIq/^xM  
{ 7kJ,;30)  
nFileLength = getFileSize(); ?C $_?Qi  
if(nFileLength == -1) J41ZQ  
{ 2l\Oufer"  
System.err.println("File Length is not known!"); S:1! )7  
} ,9A[o`b  
else if(nFileLength == -2) PMrvUM62  
{ ko, u  
System.err.println("File is not access!"); v WhtClJ3  
} {?m',sG;&  
else 5@v!wms  
{ <?Lj!JGX  
for(int i=0;i<nStartPos.length;i++) aX~iY ~?_  
{ Eydk64 5:3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); lcUL7  
} #a .aD+d'  
for(int i=0;i<nEndPos.length-1;i++) ;c;;cJc!  
{ ]]7s9PCN  
nEndPos = nStartPos[i+1]; CX1'B0=\r  
} 'E7|L@X"r  
nEndPos[nEndPos.length-1] = nFileLength; |20p#]0E+  
} LXK+WB/s  
} Sk1yend4  
V'6%G:?0a  
UhEnW8^bz1  
//启动子线程 wEkW=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3b[_0  
for(int i=0;i<nStartPos.length;i++) (JF\%Yj/  
{ QTLOP~^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =j}00,WH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ur@'X-  
nStartPos,nEndPos,i); FD`V39##  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IzL yn  
fileSplitterFetch.start(); TnKe"TA|9  
} Zd5fr c$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |H |ewVUY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sXfx[)T<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k*n5+[U^tP  
nEndPos = " + nFileLength); =XWi+')  
// fileSplitterFetch[nPos.length-1].start(); =nY*,Xu<  
@0)bY*njj  
2smLv1w@  
//等待子线程结束 : 0%V:B  
//int count = 0; ( E0be.  
//是否结束while循环 k@wxN!w;  
boolean breakWhile = false; y\@XW*_?  
0<P -`|X  
R"82=">v  
while(!bStop) RQh4RUm  
{ icnp^2P  
write_nPos(); A46y?"]/30  
Utility.sleep(500); k|g~xmI;  
breakWhile = true; IPY@9+]  
M<)HJ lr  
gGZ$}vX  
for(int i=0;i<nStartPos.length;i++) Gb MSO  
{ zx\?cF  
if(!fileSplitterFetch.bDownOver) YxsW Y7J  
{ g@S"!9[;U  
breakWhile = false; l9SbuT$U  
break; hx:x5L>  
} ^c-1w V` /  
} v4 c_UFEh<  
if(breakWhile) TYB^CVSZ  
break; P [gqv3V  
M~wJe@bc  
 o,X ?  
//count++; FfP Ce5)  
//if(count>4) 8-po|  
// siteStop(); J.*dA j  
} jT'1k[vJj  
hDfsqSK0 /  
cQN}z Ke  
System.err.println("文件下载结束!"); ;up89a-,9  
} @y}1%{,%  
catch(Exception e){e.printStackTrace ();} R[Pyrs!H  
} q,+d\-+  
_STN^   
P/0n) Q  
//获得文件长度 j4Lf6aUOX  
public long getFileSize() y=q\1~]Z  
{ ~xzRx$vU  
int nFileLength = -1; 6{1c S  
try{ <G#JPt6  
URL url = new URL(siteInfoBean.getSSiteURL()); eyUo67'7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IF@)L>-%  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rb\\6 BU0  
(uRAK  
$%sOL( r  
int responseCode=httpConnection.getResponseCode(); 4GaF:/  
if(responseCode>=400) p+A#t~K  
{ S^~GI$  
processErrorCode(responseCode); >D*L0snjV  
return -2; //-2 represent access is error +]Ydf^rF  
} NbfV6$jo  
-4"E]f  
Oi=kL{DG:s  
String sHeader; VBsS1!g  
{6A3?q  
&s\w: 9In  
for(int i=1;;i++) Lymy/9  
{ Ga$+x++'*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xgc@cwd  
//Utility.log(in.readLine()); XG*Luc-v  
sHeader=httpConnection.getHeaderFieldKey(i); 6x6PP}IX  
if(sHeader!=null) .3!=]=  
{ >H?8?a D  
if(sHeader.equals("Content-Length")) rsA K0R+  
{ HPm12&8,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); C:zK{+  
break; FhS:.  
} ?MyXii<a  
} e=TB/W_  
else vA:1z$m  
break; X8p-VCkV  
} De\&r~bTW9  
} Ll%[}C?~]?  
catch(IOException e){e.printStackTrace ();} $^}?98m  
catch(Exception e){e.printStackTrace ();} }"%tlU!}  
Bo_Ivhe[m  
9>\s81^  
Utility.log(nFileLength); b=`h""u  
xR\$2(  
27G6C`}  
return nFileLength; 0Ocy$  
} t%V!SvT8+  
8`kK)iCq  
Mb uD8B  
//保存下载信息(文件指针位置) XeKIue@_  
private void write_nPos() HTvA]-AuM  
{ 8( 7DW |\  
try{ +P81&CaY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Hh4$Qr;R  
output.writeInt(nStartPos.length); BUuNI_?M#5  
for(int i=0;i<nStartPos.length;i++) iLNKC'  
{ JZ]4?_l  
// output.writeLong(nPos); tJ i#bg%  
output.writeLong(fileSplitterFetch.nStartPos); b_:]Y<{> f  
output.writeLong(fileSplitterFetch.nEndPos); m "h{HgJd  
} seB ^o}  
output.close(); -y)ij``VY  
} }RDGk+x7|  
catch(IOException e){e.printStackTrace ();} oxha8CF]D  
catch(Exception e){e.printStackTrace ();} >7p?^*&7;  
} SBg BZm}%  
3g`uLA X>u  
:q<8:,rP  
//读取保存的下载信息(文件指针位置) 00[Uk'Q*5  
private void read_nPos() n0:'h}^  
{ a2SMNC]  
try{ xJ:15eDC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g VplBF7{  
int nCount = input.readInt(); m?V4r#t  
nStartPos = new long[nCount];  bF0 y`  
nEndPos = new long[nCount]; 4%0eX]  
for(int i=0;i<nStartPos.length;i++) #ih(I7prH  
{ T'"aStt6  
nStartPos = input.readLong(); N p$pz  
nEndPos = input.readLong(); odD^xg"L  
} kG^DHEne  
input.close(); /Q 8E12  
} ?YOH9%_cs  
catch(IOException e){e.printStackTrace ();} Lo5itW  
catch(Exception e){e.printStackTrace ();} !-_0I:m  
} rzsb(  
[kM)K'-  
vT#zc)j  
private void processErrorCode(int nErrorCode) Ep>3%{V  
{ s{4|eYR  
System.err.println("Error Code : " + nErrorCode); # y%Q{  
} %O#)=M~  
R'`q0MoN1  
U R>zL3  
//停止文件下载 $e)d!m.  
public void siteStop() J=JYf_=4bc  
{ ~Pq1@N>n  
bStop = true; FctqE/>}I  
for(int i=0;i<nStartPos.length;i++) oi^2Pvauh  
fileSplitterFetch.splitterStop(); 33z)F  
^1sX22k  
lTBPq?4{  
} *NHBwXg+  
}  \09eH[  
//负责部分文件的抓取 _~ZNX+4  
**FileSplitterFetch.java /7/d u[P6  
*/ OX d617  
package NetFox; B2w\  
-!f)P=S  
"l&=a1l  
import java.io.*; 8QDs4Bv|  
import java.net.*; TPH`{  
ViIt 'WX  
$hZb<Xz  
public class FileSplitterFetch extends Thread { sEP-jEuwG  
fl#gWAM  
(Z;;v|F.i=  
String sURL; //File URL <5X?6*Qvr  
long nStartPos; //File Snippet Start Position r~&"D#)sy  
long nEndPos; //File Snippet End Position #; CC"  
int nThreadID; //Thread's ID >>oR@  
boolean bDownOver = false; //Downing is over #9M6 q  
boolean bStop = false; //Stop identical ^x-vOG lR  
FileAccessI fileAccessI = null; //File Access interface uu@Y]0-  
B8 ;jRY  
PY- 1 oP  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /n;Ll](ri  
{ :34]}`-  
this.sURL = sURL; `?r]OVe{y  
this.nStartPos = nStart; S{' /=Px+  
this.nEndPos = nEnd; ErIAS6HS'  
nThreadID = id; U ]jHe  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KE!aa&g  
} `@1y|j:m  
lO3W:,3_a  
dfl| 6R  
public void run() S<HR6Xw  
{ pESlBQ7{I  
while(nStartPos < nEndPos && !bStop) =oQw?,eY  
{ +y'V  
^PA >t$  
x(pq!+~K  
try{ c@;$6WSG^  
URL url = new URL(sURL); ilJeI@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); = }0M^F  
httpConnection.setRequestProperty("User-Agent","NetFox"); {5w'.Z]0v  
String sProperty = "bytes="+nStartPos+"-"; (WZKqt)S"o  
httpConnection.setRequestProperty("RANGE",sProperty); 0goKiPx  
Utility.log(sProperty); "h?;)Ye  
K;moV| j  
:ZG^`H/X1d  
InputStream input = httpConnection.getInputStream(); & 9X`tCnL  
//logResponseHead(httpConnection); -;9pZ'r  
|`d,r.+P7  
['~j1!/;6  
byte[] b = new byte[1024]; '?7th>pC  
int nRead; ii&{gC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b Lag&c)  
{ ~_<I}!j/B  
nStartPos += fileAccessI.write(b,0,nRead); $.{CA-~%[  
//if(nThreadID == 1) KzD5>Xf]4$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o (fZZ`6Y  
} g-lF{Z  
5y-8_)y8o  
AKs=2N> 7  
Utility.log("Thread " + nThreadID + " is over!"); C$Pe<C#  
bDownOver = true; 2ED^uc: 0S  
//nPos = fileAccessI.write (b,0,nRead); gSLwpIK%  
} 5dOA^P@`,M  
catch(Exception e){e.printStackTrace ();} %.^8&4$+  
} =qPk'n9i8  
} Q-;ltJ  
N5 ITb0Tv  
}%LwaRT  
//打印回应的头信息 `~|8eKFq!  
public void logResponseHead(HttpURLConnection con) pgT XyAP{  
{ U7O]g'BP  
for(int i=1;;i++) 6&V4W"k  
{ \;AW/& Ea  
String header=con.getHeaderFieldKey(i); ~um+r],@@  
if(header!=null) ;m6Mm`[i<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wUkLe-n,dE  
Utility.log(header+" : "+con.getHeaderField(header)); 3?|gBiX  
else gEC*JbA.3  
break; F%QZe*m[  
} p_h)|*W{  
} *4}l V8  
$__e7  
qZRx,^gd  
public void splitterStop() 04-phEA2Q  
{ Cr0 \7  
bStop = true; Y#'mALC2  
} qT]Bl+h2  
jRIjFn|~{Y  
. 2_t/2  
}  /;LteBoY  
k 1;,eB  
JHpoW}7QB  
/* pL`snVz  
**FileAccess.java ONQp-$  
*//文件访问(定位,写) KI(9TI *  
package NetFox; - bL 7M5  
import java.io.*; +o&E)S}wP  
VU,\OOp  
9HMW!DSK`  
public class FileAccessI implements Serializable{ AMqu}G  
: sIZ+3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G#V5E)Dx  
RandomAccessFile oSavedFile; w`XwW#!}@$  
long nPos; `K[:<p}  
tm\ <w H  
wqDRFZ1*P  
public FileAccessI() throws IOException g*8LdH 6mq  
{ 6_/oVvd  
this("",0); !ZP1?l30  
}  |u 8hxa  
X;_0"g  
c)Ft#vzg&e  
public FileAccessI(String sName,long nPos) throws IOException #u+BjuZo  
{ 6w{^S~rqo  
oSavedFile = new RandomAccessFile(sName,"rw"); 2,|*KN*e`W  
this.nPos = nPos; =y>P>&sI  
oSavedFile.seek(nPos); 0^44${bA  
} 3}O.B r|  
g3{)AX[Uy  
e #l/jFJU  
public synchronized int write(byte[] b,int nStart,int nLen) rN? L8  
{ -F,o@5W>Y  
int n = -1; U,/NygB~  
try{ R`=IYnoOA  
oSavedFile.write(b,nStart,nLen); #|*;~:fz  
n = nLen; }8Wp X2U  
} #r 1 $=GY  
catch(IOException e) z79L2lJn  
{ |7WzTz  
e.printStackTrace (); &|<~J (L;  
} .UbmU^y|  
;@K,>$ur-  
G[u_Uu=>  
return n; Q(m} Sr4  
} G 8|[.n  
AG) N^yd  
[:$j<}UmB  
} /b@0HL?  
>K#Z]k  
Jl3l\I'  
/* !7J;h{3Uw  
**SiteInfoBean.java Z91gAy^z<  
*/ +Cx~4zEq  
package NetFox; "r cPJX  
9b]*R.x:$&  
~QBf78@Gf  
public class SiteInfoBean { $';'MoS  
S,AZrgh,"X  
l@1f L%f  
private String sSiteURL; //Site's URL sLbz@54  
private String sFilePath; //Saved File's Path toTAWT D  
private String sFileName; //Saved File's Name /dOQ4VA\  
private int nSplitter; //Count of Splited Downloading File =i%2/kdi0b  
PyYKeo=  
0x^$q? \A  
public SiteInfoBean() T<zonx1  
{//nSplitter的缺省值为5 cdU2ph_  
//default value of nSplitter is 5 R$,`}@VqZ3  
this("","","",5); nq/xD;q  
} ?0[%+AD hM  
&[cL%pP  
w])~m1yW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ec1g7w-n  
{  4EB$e?  
sSiteURL= sURL; eV9:AN}K=  
sFilePath = sPath; K 1:F{*  
sFileName = sName; 2SG|]=  
this.nSplitter = nSpiltter; ^0{S!fs  
m_rRe\  
.e.vh:Sz  
} oK5(,8 (4  
8GlH)J+kq  
Rz=]KeZu  
public String getSSiteURL() |w~zh6~  
{ rLL;NTN+/  
return sSiteURL; ]v_xEH}T  
} MW*}+ PCY  
iXl1S[.l  
DA@ { d-A  
public void setSSiteURL(String value) [&3"kb  
{ NlcWnSv  
sSiteURL = value; ,7%(Jj$ ^  
} ;o^m"I\y  
G#@<bg3  
;k/0N~  
public String getSFilePath() ^;@Bz~Z  
{ '3hvR4P  
return sFilePath; ^* DKF  
} :+Dn]:\  
KAsS= `  
KMbBow3o*~  
public void setSFilePath(String value) GUN<ZOYb=  
{ Ds}6{']K  
sFilePath = value; Wnf`Rf)1z  
} |=%$7b\C  
a}>GQu*y  
J.?p?-"  
public String getSFileName() ae!_u \$  
{ }f-rWe{gs>  
return sFileName; IL%&*B  
}  W2^eE9  
aO<d`DTyJ  
nAts.pVy"  
public void setSFileName(String value) V|a 59 [y?  
{ 9h0|^ttF  
sFileName = value; > %Y#(_~a  
} nQ~q -=,L  
uwQ4RYz  
,MvvW{EY  
public int getNSplitter() MPL2#YU/a  
{ 1}ToR=  
return nSplitter; [e^i".  
} ;N1FP*  
k2+Z7#2n  
}<Me%`x"  
public void setNSplitter(int nCount) ?1412Tq5  
{ +M.|D,wg2  
nSplitter = nCount; rW6w1  
} *v5y]E%aW  
} a9qZI  
g)p[A 4  
%##9.Xm6l  
/* 1^W Aps  
**Utility.java Bkz   
*/ JGdBpj:  
package NetFox; 9a4RW}S<  
;zJ_apZ:{  
%vThbP#mR|  
public class Utility { _9gn;F  
 C3<3  
[X=eCHB?  
public Utility() X0P$r6 ;  
{ ePY K^D  
eb8_guZ  
Q@j:b]Y9  
} q{5Vq_s\  
oDP|>yXC)  
//线程睡眠 }`g*pp*  
public static void sleep(int nSecond) Anm5Cvt;i  
{ Ux<h` s  
try{ Fwqv 1+  
Thread.sleep(nSecond); _j2`#|oG  
} kN) pi "  
catch(Exception e) *lTu-  
{ JC+VG;kcs  
e.printStackTrace (); w'e enIX^^  
} QMsnfG  
} EPg?jKZava  
e,4G:V'NX  
//日志 F3f>pK5  
public static void log(String sMsg) Bh.'%[',  
{ 'qD9k J`  
System.err.println(sMsg); tw(2V$J  
} %B?5l^W@  
z>&D~0  
d+w<y~\ q  
public static void log(int sMsg) jGWLYI=V2  
{ 3z ry %qV=  
System.err.println(sMsg); BA5= D>T-  
} x~z 2l#ow  
} -|T^  
Af%?WZlOq  
FP Mk&  
/* ;K_B,@:'  
**TestMethod.java ditzl(L   
*/ x?F{=\z/o  
package NetFox; p?h;Sv/  
INT2i8oU  
zJy{Ry[Sb  
public class TestMethod { %)e+w+  
*~"`&rM(  
&ar}6eO  
public TestMethod() g\Z k*5(  
{ ///xx/weblogic60b2_win.exe aD^MoB3  
try{ @88 efF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D0P% .r"v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9%wppNT/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); q8lK6p\:W  
fileFetch.start(); r6)1Y`K=9  
} n" ~*9'  
catch(Exception e){e.printStackTrace ();} pWp2{G^XB  
r/v&tU  
+OmSR*fA0  
} ig,|3(  
vOS0E^  
5zGj,y>u  
public static void main(String[] args) WWL Vy(  
{ _7<U[63  
new TestMethod(); :6 fQE#(s&  
} QUDVsN#  
} Ss:,#|   
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