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http断点续传简单实现(java)

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/* db.iMBki  
**SiteFileFetch.java Xg,E;LSF8  
*/ >L&>B5)9  
package NetFox; 7F|T5[*l  
import java.io.*; QdC>fy  
import java.net.*; r(cS{oni  
VCbnS191*  
OWOj|jM  
public class SiteFileFetch extends Thread { G;fP  
ix7N q7!N  
z%*ZmF^K  
SiteInfoBean siteInfoBean = null; //文件信息Bean + ` Em&  
long[] nStartPos; //开始位置 ub,Sj{Mq"  
long[] nEndPos; //结束位置 [|k@Suv |z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O$$s]R6  
long nFileLength; //文件长度 [(#ncR8B  
boolean bFirst = true; //是否第一次取文件 I!# 42~\  
boolean bStop = false; //停止标志 Gt6$@ji4u  
File tmpFile; //文件下载的临时信息 tQ?? nI2  
DataOutputStream output; //输出到文件的输出流 oB_{xu$6|  
Q6.},o  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  U]e;=T:3  
public SiteFileFetch(SiteInfoBean bean) throws IOException l6l)M  
{ HpNf f0c  
siteInfoBean = bean; k*z)AR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K +w3YA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1C.<@IZ  
if(tmpFile.exists ()) m{R`1cN=Hg  
{ g ~10K^  
bFirst = false; *QAK9mc  
read_nPos(); Z[0xqGYLB  
} evimnV  
else mKxQ U0`  
{ 17<\Q(YQ=  
nStartPos = new long[bean.getNSplitter()]; -fG;`N5U  
nEndPos = new long[bean.getNSplitter()]; U&`M G1uHe  
} ajkRL|^  
<k<  
v C><N  
lv$tp,+  
} gfih;i.pY  
AO8`ItNZdT  
#MOEY|6  
public void run() tOp>O oD  
{ <5C3c&sds  
//获得文件长度 61!R -  
//分割文件 }ZvL%4jT  
//实例FileSplitterFetch 0%'&s)#  
//启动FileSplitterFetch线程 ^(UL$cQ>  
//等待子线程返回 nW{7L  
try{ -] J V  
if(bFirst) p1G!-\l  
{ Mg^GN -l  
nFileLength = getFileSize(); NbG3^(  
if(nFileLength == -1) V/762&2X  
{ sbkWJy  
System.err.println("File Length is not known!"); &*MwKr<y  
} a#j0N5<Nl  
else if(nFileLength == -2) ZIpL4y =_  
{ H$1R\rE`  
System.err.println("File is not access!"); EkjO4=~UC  
} roW8 4x  
else s:;!QIC5jo  
{ nuKjp Ap!  
for(int i=0;i<nStartPos.length;i++)  b.C!4^  
{ 3}LTEsdM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #Q$9Eq8"[  
} &#;UKk~)Of  
for(int i=0;i<nEndPos.length-1;i++) 1_GUi  
{ MlS<txFPS  
nEndPos = nStartPos[i+1]; ?L{[84GSO  
} hQ8/-#LO_  
nEndPos[nEndPos.length-1] = nFileLength; Wl::tgU  
} P) GBuW  
} mj S)*@F  
gZ/M0px  
/lAt&0  
//启动子线程 #/5jWH7U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I^\YD9~=x  
for(int i=0;i<nStartPos.length;i++) ] hL 1qS  
{ "'II~/9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KQQR"[z&V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1 ljgq]($  
nStartPos,nEndPos,i); HtmJIH:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oACuI|b  
fileSplitterFetch.start(); JBi<TDm/  
} ddlLS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'iUfr@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V:My1R0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <E$5LP;:  
nEndPos = " + nFileLength); 'S@C,x%2,  
// fileSplitterFetch[nPos.length-1].start(); Qmzj1e$6x  
>!`T=(u!  
/g@.1z1w  
//等待子线程结束 ,C(")?4aJ  
//int count = 0; &``;1/J*W  
//是否结束while循环 cKFzn+  
boolean breakWhile = false; ?sp  
*vUKh^="  
0(:"q!h  
while(!bStop) />K$_T/]  
{ &[qL l  
write_nPos(); bWUo(B#*I  
Utility.sleep(500); ]W-:-.prh  
breakWhile = true; Zp l?zI  
N;<<-`i  
T4o}5sq}S  
for(int i=0;i<nStartPos.length;i++) eP[azC"G[  
{ Aw9^}k}UfD  
if(!fileSplitterFetch.bDownOver) jyLpe2 S  
{ f>-OwL($P  
breakWhile = false; D|`[ [  
break; lj'c0k8  
} " 0K5 /9  
} )#IiHBF  
if(breakWhile) xREqcH,vU  
break; >Y)jt*vQ  
FU5vo  
mi%d([)%<  
//count++; YNHn# 98\  
//if(count>4) 1ciP+->$  
// siteStop(); w*$nG$  
} 8WfF: R;  
5pE[}@-c9  
hY/SR'8  
System.err.println("文件下载结束!"); 7PHvsd"]p  
} ~*THL0]~  
catch(Exception e){e.printStackTrace ();} qmtVk  
} B5zu?AG  
[1 w  
YeYFPi#  
//获得文件长度 h*h+VM  
public long getFileSize() .+|G`*1<i  
{ Pm7,Nq)<>n  
int nFileLength = -1; mNWmp_c,1  
try{ ?fCLiK  
URL url = new URL(siteInfoBean.getSSiteURL()); l J;wl|9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q8P| ]  
httpConnection.setRequestProperty("User-Agent","NetFox"); =n i&*&  
>umcpkp- h  
lmQ!q>N  
int responseCode=httpConnection.getResponseCode();   VG q'  
if(responseCode>=400) ]^/:Xsk$  
{ KX[_eO L  
processErrorCode(responseCode); >bEH&7+@_'  
return -2; //-2 represent access is error -O^b  
} ZTM zL%i  
T_y 'cvh  
Uj1^?d+b  
String sHeader; dB^J}_wp  
9\R:J"X  
*N[.']#n  
for(int i=1;;i++) O&E1(M|*>  
{ Y>wpla[kUq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o5i?|HJ  
//Utility.log(in.readLine()); r-H~MisL  
sHeader=httpConnection.getHeaderFieldKey(i); vA;ml$  
if(sHeader!=null) !ck=\3pr  
{ $9M>B<]  
if(sHeader.equals("Content-Length")) P\*-n"  
{ ?dC[VYC\^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ga+\b>C  
break; fw|r{#d  
} XDz![s  
} {jJUS>  
else Ep.,2H  
break; #xm<|s   
} Cdot l$'  
} D0us<9q  
catch(IOException e){e.printStackTrace ();} =@G#c5H*  
catch(Exception e){e.printStackTrace ();} bhnm<RZ  
m:/nw,  
It(8s)5  
Utility.log(nFileLength); yL_-w/a  
J &u&G7#S  
 ]i=-/  
return nFileLength; 2fFNJ  
} Q^b_+M  
9Rb-QI  
&gIu<*u<  
//保存下载信息(文件指针位置) V[rNJf1z  
private void write_nPos() ^$`xUKp`pn  
{ Rr|VGtg  
try{ =LZj6'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $_@~t$  
output.writeInt(nStartPos.length); aVO5zR./)  
for(int i=0;i<nStartPos.length;i++) 0A9x9l9Wd  
{ "n7rbh3VW  
// output.writeLong(nPos); OzX\ s=  
output.writeLong(fileSplitterFetch.nStartPos); `P)1RTVx  
output.writeLong(fileSplitterFetch.nEndPos); w`c9_V  
} va95/(  
output.close(); %R7Q`!@8  
} V7[Dvg:W  
catch(IOException e){e.printStackTrace ();} />FrMz8;(  
catch(Exception e){e.printStackTrace ();} V`pTl3  
} X>wB=z5PXK  
s lDxsb  
/49PF:$?  
//读取保存的下载信息(文件指针位置) r*0a43mC1  
private void read_nPos() U@ALo  
{ `(_cR@\  
try{ &:S_ewJK7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N+"Y@X yg  
int nCount = input.readInt(); "5synfO  
nStartPos = new long[nCount]; jE&kN$.7j  
nEndPos = new long[nCount]; |Rhx&/  
for(int i=0;i<nStartPos.length;i++) Ty*ec%U9F  
{ E@JxY  
nStartPos = input.readLong(); GWM2l?zOP  
nEndPos = input.readLong(); 'R*xg2!i  
}  !|9$  
input.close(); (W5E\hjJ  
} 5#80`/w^U  
catch(IOException e){e.printStackTrace ();} jMzHs*:  
catch(Exception e){e.printStackTrace ();} qaA\.h7  
} /21d%T:}  
]i8K )/  
>|o-&dk  
private void processErrorCode(int nErrorCode) mkk74NY  
{ c1jHg2xim  
System.err.println("Error Code : " + nErrorCode); }2:bYpYQ  
} -,TBUWg  
m{JiF-=u  
Bag2sk  
//停止文件下载 E:D1ZV  
public void siteStop() SV<*qz  
{ v@XQ)95]F  
bStop = true; bL)g+<:F  
for(int i=0;i<nStartPos.length;i++) #h6(DuViKw  
fileSplitterFetch.splitterStop(); Q= + Frsk  
.sbU-_ij@U  
= <O{t#]  
} +y6|Nq  
} zv@'x nY]  
//负责部分文件的抓取 ojs&W]r0Z  
**FileSplitterFetch.java q&<#)#+  
*/ /q uf'CV}  
package NetFox; :0CR=]WM  
R`76Ae`R8  
H'q&1^w)  
import java.io.*; Dr6Br<yi  
import java.net.*; 6x]|IWvW  
?uU0NKZA  
KjZ^\lq'  
public class FileSplitterFetch extends Thread { Pl}}!<!<z  
[l- zU}u&v  
,^26.p$  
String sURL; //File URL 6lT1X)  
long nStartPos; //File Snippet Start Position l YH={jJ  
long nEndPos; //File Snippet End Position ]1)@.b;QR  
int nThreadID; //Thread's ID \#LKsQa  
boolean bDownOver = false; //Downing is over ,*E%D _  
boolean bStop = false; //Stop identical }sPY+ZjV  
FileAccessI fileAccessI = null; //File Access interface +(/XMx}a  
@!0j)5%  
>h[tHM O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException thipfS  
{ %f6l"~y  
this.sURL = sURL; w?jmi~6  
this.nStartPos = nStart; xXA$16kd  
this.nEndPos = nEnd; g~FB&U4c  
nThreadID = id; XhWMvme  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l]sO[`X  
} v0"|J3  
I;P?P5H  
X-:Ni_O\ty  
public void run() M\\TQ(B  
{ ])m",8d&T  
while(nStartPos < nEndPos && !bStop) Ef%8+_  
{ iN`/pW/JE  
eb9qg.9Z  
n 8AND0a1C  
try{ "*+epC|ks  
URL url = new URL(sURL); *9j9=N?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *uA?}XEfi  
httpConnection.setRequestProperty("User-Agent","NetFox"); K8|6r|x  
String sProperty = "bytes="+nStartPos+"-"; g?`D8  
httpConnection.setRequestProperty("RANGE",sProperty); 4fzq C)  
Utility.log(sProperty); 5CU< ?  
"Y(S G  
R^1= :<)C  
InputStream input = httpConnection.getInputStream(); OiM{@  
//logResponseHead(httpConnection); &=$8 v"&^  
ngeX+@  
EF"ar  
byte[] b = new byte[1024]; w2+RX-6Ie  
int nRead; LTzf&TZbx5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hXz"}X n  
{ 9?,n+  
nStartPos += fileAccessI.write(b,0,nRead); F<V zVEx  
//if(nThreadID == 1) }Lb];hww1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wv=L_E_  
} ,Yi =s;E  
I=(O,*+PQ  
aj(M{gFq~  
Utility.log("Thread " + nThreadID + " is over!"); )&_{m K  
bDownOver = true; zE<vFP-1v  
//nPos = fileAccessI.write (b,0,nRead); CvbY2_>Nh  
} X@~sIUXx9  
catch(Exception e){e.printStackTrace ();} {E6W]Mno  
} ?ZDx9*f  
} sv0kksj  
`Z%XA>  
*2:)Rf  
//打印回应的头信息 Ae ue:u>  
public void logResponseHead(HttpURLConnection con) M\`6H8aLn  
{ 6bHj<6>MX  
for(int i=1;;i++) .*Hv^_  
{ A]H+rxg  
String header=con.getHeaderFieldKey(i); ^<y$+HcH  
if(header!=null) < "~k8:=4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~-W.yg6D{  
Utility.log(header+" : "+con.getHeaderField(header)); m.V mS7_I  
else 5.GBd_;  
break; P92:}" )*>  
} g^0  
} Z :Kob b  
;P2~cQjD;  
Jt)<RMQ^R  
public void splitterStop() =602%ef\  
{ #e8CuS  
bStop = true;  K[?wP>s  
} FfD2 &(-R  
29av8eW?3  
HnY: gu  
} 3_33@MM  
X,y$!2QI  
%'g/4I  
/* u{H_q&1  
**FileAccess.java Pyyx/u+?@  
*//文件访问(定位,写) brTB /(E  
package NetFox; 7XR[`Tn9<  
import java.io.*; P `2Rte6s  
58v5Z$%--  
u[dI81`  
public class FileAccessI implements Serializable{ V KR6i  
YO,GZD`-o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pkk0?$l ",  
RandomAccessFile oSavedFile; niA{L:4  
long nPos; ~4\bR  
7,+:Q Y@  
)%MB o.NL  
public FileAccessI() throws IOException rcyH2)Y/e  
{ As)-a5!  
this("",0); ,%,}[q?]d  
} bjvi`jyL3k  
wkIH<w|jb  
:$}67b)MO  
public FileAccessI(String sName,long nPos) throws IOException ^ )+tn  
{ *{-XN  
oSavedFile = new RandomAccessFile(sName,"rw"); ~V./*CQ\c  
this.nPos = nPos; .5I1wRN49  
oSavedFile.seek(nPos); a\%g_Q){  
} 0e}L Z,9e  
Xt7uCs  
D!@c,H  
public synchronized int write(byte[] b,int nStart,int nLen) ?ii a  
{ S8]g'!  
int n = -1; 99ZQlX  
try{ RKBtwZx>f  
oSavedFile.write(b,nStart,nLen); \}<nXn!  
n = nLen; ]"YG7|EU  
} i\t4TdEx(  
catch(IOException e) nKHyq\  
{ ?VzST }  
e.printStackTrace (); L~0B  
} t;4{l`dk  
`[:f;2(@  
 Ng-3|N  
return n; Pd@?(WQ  
} ^$T>3@rDB  
G4=v2_]  
9^aMmN&6N2  
} :_?>3c}L  
GJ((eAS)  
2smLv1w@  
/* U,+=>ns>  
**SiteInfoBean.java CF$^we  
*/ y\@XW*_?  
package NetFox; 0<P -`|X  
R"82=">v  
RQh4RUm  
public class SiteInfoBean { K}wUM^  
A46y?"]/30  
k|g~xmI;  
private String sSiteURL; //Site's URL IPY@9+]  
private String sFilePath; //Saved File's Path R_ Z H+@O  
private String sFileName; //Saved File's Name #nu?b?X'  
private int nSplitter; //Count of Splited Downloading File fYH%vr)  
fo5!d@Nv  
ikofJl]9  
public SiteInfoBean() z}pdcQl#  
{//nSplitter的缺省值为5 l9SbuT$U  
//default value of nSplitter is 5 hx:x5L>  
this("","","",5); \Mi y+<8$  
} 9 s>JdAw?  
XLzHm&;  
~A6QX8a  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M~wJe@bc  
{ BGUP-_&  
sSiteURL= sURL; 8WaVs6  
sFilePath = sPath; 7[8PSoo  
sFileName = sName; paiF ah  
this.nSplitter = nSpiltter; km8[azB o  
+='.uc_  
j[c|np4k\  
} SFh6'v'1N@  
Z,Q)\W<'-  
c"fnTJXr79  
public String getSSiteURL() M#2DI?S@  
{ Mb+cXdZb  
return sSiteURL; Blf;_e~=[j  
} ^Dd$8$?[  
 DMf:u`<  
:GO}G`jY  
public void setSSiteURL(String value) ^OYar(  
{ \f%jN1z  
sSiteURL = value; ~I!7]i]"*?  
} QZzi4[-as  
N|8TE7- F|  
O[q {y  
public String getSFilePath() dx:],VB  
{ 6R#f 8  
return sFilePath; ]X{LZYk  
} !R4`ihi1  
&{"aD&  
;JDxl-~  
public void setSFilePath(String value) MT|}[|_  
{ 9r8*'.K`Z  
sFilePath = value; Q7f\ 5QjT  
} gP)g_K(e  
&|55:Y87  
5H>[@_u+:  
public String getSFileName() l*/I ; a$  
{ n Hy|  
return sFileName; {3!v<CY'  
} `|Tr"xavf  
k%Jw S_F  
q]<cn2  
public void setSFileName(String value) gNN{WFHQX:  
{ \u2p]K>  
sFileName = value; aQw?r  
} mZ*!$P:vy"  
A=E1S{C  
 s y#CR4X  
public int getNSplitter() }<A\>  
{ [,$] %|6wt  
return nSplitter; 2et7Vw  
} MyAi)Mz~o  
 I=|b3-  
tec CU[O  
public void setNSplitter(int nCount) hQPiGIs  
{ XkOsnI8n  
nSplitter = nCount; d\D.l^  
} ^q7 fN0"6  
} \h?C G_|]  
: xB<Rq  
/J8y[aa  
/* (wnkdI{  
**Utility.java ErHbc 2  
*/ U c$RYPq  
package NetFox; K`768 %q  
9UZKL@KC  
jL>IX`,+6  
public class Utility { 8( 7DW |\  
Hq3"OMGq  
q:+,'&<D  
public Utility() $62!R]C9\  
{ O}"VK  
pQ!NhzQ  
(%YFcE)SRS  
} M)#aX|%Mh  
-]\UFR  
//线程睡眠 v:nm#P%P  
public static void sleep(int nSecond) ;1A4p`)  
{ yk,o*g  
try{ 8dNwi&4  
Thread.sleep(nSecond); 7q^o sOj"  
} y08.R. l  
catch(Exception e) |Xlpgdiu  
{ :4;ZO~eq!  
e.printStackTrace (); F /IXqj  
} B{PI&a9~s%  
} >A;Mf*E  
CMI%jyiX  
//日志  bF0 y`  
public static void log(String sMsg) 4%0eX]  
{ #ih(I7prH  
System.err.println(sMsg); T'"aStt6  
} N p$pz  
d @<(Z7|  
3Gubq4r  
public static void log(int sMsg) T;IaVMFG|d  
{ x$tx!%,)/S  
System.err.println(sMsg); FO&U{(Q  
} 2Xys;Dwx  
} k^:)|Z  
8vOKm)[%  
c,:xm=&  
/* aqSHo2]DX9  
**TestMethod.java ^OnU;8IC  
*/ \!Cix}}1  
package NetFox; Gt3V}"B3\  
N.vt5WP  
AK]{^Hvz  
public class TestMethod { ) wtVFG  
TL-sxED,,D  
(sHqzWh  
public TestMethod() y0k*iS e  
{ ///xx/weblogic60b2_win.exe GsA/pXx  
try{ XCc /\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jeXv)}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *NHBwXg+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); SV0E7qX  
fileFetch.start(); 71_{FL8  
} !o1{. V9q  
catch(Exception e){e.printStackTrace ();} =UE/GTbl  
 G?AZ%Yx  
ze@NqCF  
} aVNBF`  
DK;p6_tT  
D~E1hr&Vd>  
public static void main(String[] args) a|Io)Qhr  
{ eK PxSN Z  
new TestMethod(); h,o/(GNnW  
} j6]+ fo&3  
} +P:xB0Tm D  
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