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http断点续传简单实现(java)

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/* KzV.+f  
**SiteFileFetch.java ucw`;<d8  
*/ X*0k>j  
package NetFox; wi>DZkR  
import java.io.*; SijtTY#r  
import java.net.*; 1{^CfamF  
[!W5}=^H  
R;WW f.#  
public class SiteFileFetch extends Thread { Q-[3j  
a;%I\w;2  
w{3ycR  
SiteInfoBean siteInfoBean = null; //文件信息Bean u[)_^kIE(n  
long[] nStartPos; //开始位置 /K f L+"^|  
long[] nEndPos; //结束位置 iBucT"d]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9 +}cE**=d  
long nFileLength; //文件长度 ]*0(-@  
boolean bFirst = true; //是否第一次取文件 19'5Re&  
boolean bStop = false; //停止标志 _0K.Fk*(!  
File tmpFile; //文件下载的临时信息 U<Vy>gIC  
DataOutputStream output; //输出到文件的输出流 X1Qr _o-BR  
ThtMRB)9  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) mIvnz{_d  
public SiteFileFetch(SiteInfoBean bean) throws IOException mxgqS=`  
{ 7m\vRMK  
siteInfoBean = bean; -!l^]MU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); JRq3>P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >zQNHSi  
if(tmpFile.exists ()) C ck#Y  
{ Y.7}  
bFirst = false; n[|6khOL-  
read_nPos(); Y,'%7u  
} E$ {J  
else n!ZMTcK8  
{ mB~~_]M N  
nStartPos = new long[bean.getNSplitter()]; ^ESUMXb  
nEndPos = new long[bean.getNSplitter()]; `g--QR  
} R }1W  
0*/kGvw`i  
+,z) #  
Y17hOKc`  
} 8&%Cy'TIz4  
7#ofNH J  
"mR*7o$|  
public void run() +>!V ]S  
{ 6(Vhtr2( *  
//获得文件长度 J smB^  
//分割文件 ~T% Ui#Gc  
//实例FileSplitterFetch H;QA@tF>5  
//启动FileSplitterFetch线程 E:)Cp  
//等待子线程返回 :5jexz."M  
try{ BX*69  
if(bFirst) P].eAAXnP  
{ `kFiH*5%z  
nFileLength = getFileSize(); 9mDn KW  
if(nFileLength == -1) <6/= y1QC)  
{ 0'`S,  
System.err.println("File Length is not known!"); 6lsEGe  
} `Ug tvo  
else if(nFileLength == -2) g8RPHjvZ  
{ W!91tzs:  
System.err.println("File is not access!"); uaaf9SL?  
} ?_%u)S*g  
else ywO mQcZ  
{ QjJfE<h  
for(int i=0;i<nStartPos.length;i++) 9Sz7\W0  
{ *}w+ 68eO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); LL.x11 o3  
} wG8 nw;  
for(int i=0;i<nEndPos.length-1;i++) f0DK>L  
{ 0elxA8Z~e  
nEndPos = nStartPos[i+1]; wx*1*KZ  
} BZ+;n |<r  
nEndPos[nEndPos.length-1] = nFileLength; 6WeM rWx  
} ~>g+2]Bn>$  
} -9d%+O~v6~  
f}iU& 3S  
dw9T f^V  
//启动子线程 hO3 {  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Wo!;K|~P  
for(int i=0;i<nStartPos.length;i++) R&*@@F-dx  
{ {n&Uf{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k3>YBf`fC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H O*YBL  
nStartPos,nEndPos,i); [9AM\n>g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A?A9`w  
fileSplitterFetch.start(); DZk1ZLz  
} f@d9Hqr+l;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yQ%"U^.m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D"^'.DL@wG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e)b%`ntF  
nEndPos = " + nFileLength); gi$XB}L+X  
// fileSplitterFetch[nPos.length-1].start(); Ac`;st%l.  
{$33B'wk  
KmmQ,e%  
//等待子线程结束 2khh4?|\  
//int count = 0; ~KPv7WfG  
//是否结束while循环 4-^[%&>}  
boolean breakWhile = false; 0[Eb .2I  
)+EN$*H  
|>+uw|LtZ  
while(!bStop) Oaa"T8t  
{ (%'9CfPx  
write_nPos(); sJU`u'w  
Utility.sleep(500); qybxXK:  
breakWhile = true; ]iVLHVqz  
/iG7MC\`  
WbcS: !0  
for(int i=0;i<nStartPos.length;i++) 4TZ cc|B5  
{ 8:dQ._#v  
if(!fileSplitterFetch.bDownOver) 5FOqv=6S  
{ p$XKlg&  
breakWhile = false; a <wL#Id  
break; i\Wdo/c-H  
} %\6Q .V#s  
} s`;f2B/|  
if(breakWhile) :kG)sw7  
break; x-;`-Uo%  
3i=Iu0  
|8U;m:AS  
//count++; !Z|($21W  
//if(count>4) qINTCm j  
// siteStop(); 6Hf,6>  
} ,b|-rU\  
zk}{ dG^M:  
L;/n!k.A  
System.err.println("文件下载结束!"); G%:G eW  
} &%,DZA`  
catch(Exception e){e.printStackTrace ();} =w%Oa<  
} ej^3Y Nh&  
Md&WJ };L  
U(,.D}PG  
//获得文件长度 :_HF j.JW  
public long getFileSize() 7lA:)a_!]  
{ "#4dW7E  
int nFileLength = -1; sn{tra  
try{ Mu&x_&|  
URL url = new URL(siteInfoBean.getSSiteURL()); y{=>$C[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZA820A>2!  
httpConnection.setRequestProperty("User-Agent","NetFox"); MKg,!TELe  
t'(1I|7  
@dEiVF`4:  
int responseCode=httpConnection.getResponseCode(); /+[63=fl  
if(responseCode>=400) 1@qgF  
{ +B"0{>n}F  
processErrorCode(responseCode); ;rR/5d1!  
return -2; //-2 represent access is error $NG++N  
} Mvcfk$pA  
Z :nbZHByh  
$k%Z$NSN=  
String sHeader; s([dGD$i  
{y-^~Q"z  
rRb+_]Lg  
for(int i=1;;i++) (.23rVvnT@  
{ DL8x":;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @S3f:s0~D  
//Utility.log(in.readLine()); 7o]HQ[xO  
sHeader=httpConnection.getHeaderFieldKey(i); )jDJMi_[  
if(sHeader!=null) 'jfRt-_-  
{ >: Wau  
if(sHeader.equals("Content-Length")) ^%<pJMgdF  
{ 2`bdrRD0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (K<9h L+X  
break; l "pN90B4  
} 8dO?K*J,H'  
} E6A /SVp  
else ;[ 'a  
break; B\CN<<N>dD  
} o\=n4;S  
} HdX2YPYn;  
catch(IOException e){e.printStackTrace ();} bGmx7qt#  
catch(Exception e){e.printStackTrace ();} zm#nV Y`  
*hY2.t; X  
L%\b'fs  
Utility.log(nFileLength); wkb$^mU  
J/x2qQ$9  
N4!<Xj  
return nFileLength; @cD uhK"U}  
} v"O5u%P  
e2)autBe  
I4c!m_sr  
//保存下载信息(文件指针位置) `V!>J 1x  
private void write_nPos() s8mr''  
{ ajH"Jy3A  
try{ N#z~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); } cNW^4F  
output.writeInt(nStartPos.length); ~Y!kB:D5;~  
for(int i=0;i<nStartPos.length;i++) +OHGn;C  
{ U1R4x!ym4  
// output.writeLong(nPos); LIpEQ7;  
output.writeLong(fileSplitterFetch.nStartPos); TnH\O$  
output.writeLong(fileSplitterFetch.nEndPos); Ip *g'  
} wdas1  
output.close(); 3HC  
} }}{Yw  
catch(IOException e){e.printStackTrace ();} kxB.,'  
catch(Exception e){e.printStackTrace ();} gP}+wbk  
}  IDFFc&  
p Pro }@@  
5/0j}_pP  
//读取保存的下载信息(文件指针位置) (p)!Mq "^  
private void read_nPos() sM2MLh'D  
{ `BXS)xj  
try{ c-4STPNQi  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dp5cDF}l  
int nCount = input.readInt(); ku&k'V  
nStartPos = new long[nCount]; HIvZQQW|  
nEndPos = new long[nCount]; j}JZ  
for(int i=0;i<nStartPos.length;i++) F7}-!  
{ YwDt.6(+,  
nStartPos = input.readLong(); ^QX bJJ  
nEndPos = input.readLong(); Bi%x`4Lf  
} 1NLg _UBOK  
input.close(); {S.>BXX  
} V"KS[>>f  
catch(IOException e){e.printStackTrace ();} L,_.$1d  
catch(Exception e){e.printStackTrace ();} a[!%L d  
} N"7]R[*  
t0E51Ic@  
B4H!5b  
private void processErrorCode(int nErrorCode) g_.^O$}  
{ t+Bf#:  
System.err.println("Error Code : " + nErrorCode); :!TI K1  
} FY3IUG  
qSU| =  
2umv|]n+l|  
//停止文件下载 #1nJ(-D+  
public void siteStop() TLa]O1=Bf.  
{ o*S"KX $  
bStop = true; Tl("IhkC  
for(int i=0;i<nStartPos.length;i++) >bo'Y9C  
fileSplitterFetch.splitterStop(); _GYMPq\%L#  
w Iv o"|%  
Vm1-C<V9  
} A<MtKb  
} `)$_YZq|SR  
//负责部分文件的抓取 0#p/A^\#7M  
**FileSplitterFetch.java e]8,:Gd(  
*/ Am4lEvb  
package NetFox; $&I 'o  
5g5'@vMN  
fz_nsVD  
import java.io.*;  ZI>km?w  
import java.net.*; v $({C  
KA s1(oG  
afG{lWE)  
public class FileSplitterFetch extends Thread { ~.g3ukt  
fPa9ofU/kr  
?}QH=&=^  
String sURL; //File URL RVw9Y*]b  
long nStartPos; //File Snippet Start Position clO,}Ph>  
long nEndPos; //File Snippet End Position uKr1Z2  
int nThreadID; //Thread's ID SI:ifR&T  
boolean bDownOver = false; //Downing is over 2][DZl  
boolean bStop = false; //Stop identical 4Ft1@  
FileAccessI fileAccessI = null; //File Access interface  Ukz;0q  
u'~;Y.@i'  
5`+5{p  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j7QX ,_Q  
{ ?uLeFD  
this.sURL = sURL; uzr\oj+>  
this.nStartPos = nStart; B2=\2<  
this.nEndPos = nEnd; o2H1N~e#c  
nThreadID = id; WN]<q`.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ' I}: !Z  
} Rqip kx  
tfO#vw,@  
<[ Xw)/#  
public void run() S56]?M|[  
{ I3b"|%  
while(nStartPos < nEndPos && !bStop) [I*! lbt  
{ mB'3N;~  
jdA ]2]  
v-j3bB  
try{ \K2*Q&>  
URL url = new URL(sURL); o89( h!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6aft$A}XnD  
httpConnection.setRequestProperty("User-Agent","NetFox"); nSx8E7 |V  
String sProperty = "bytes="+nStartPos+"-"; -T@`hk`  
httpConnection.setRequestProperty("RANGE",sProperty); ~EiH-z4U  
Utility.log(sProperty); PyC0Q\$%  
(?)7)5H  
X@N$Z{  
InputStream input = httpConnection.getInputStream(); U\@A _ B  
//logResponseHead(httpConnection); w*7|dZk{  
Wzq>JNn y  
-Yi,_#3{  
byte[] b = new byte[1024]; )Q;978:  
int nRead; KxGX\   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {2d_"lHBt  
{ $RX'(/  
nStartPos += fileAccessI.write(b,0,nRead); Sb2v_o  
//if(nThreadID == 1) + xv!$gJEj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @exey  
} oih5B<&f#  
{^)70Vz>PE  
Pn.bVV:  
Utility.log("Thread " + nThreadID + " is over!"); K+\nC)oG  
bDownOver = true; AEirj /  
//nPos = fileAccessI.write (b,0,nRead); "d/s5sP|S  
} '_s}o<  
catch(Exception e){e.printStackTrace ();} {Bvj"mL]j  
} F?+3%>/A @  
} {BBw$m,o  
RrrK*Fk8=  
W[bmzvJ_X  
//打印回应的头信息 ;E;To\NCYF  
public void logResponseHead(HttpURLConnection con) E`\8TqO  
{ +]xFoH  
for(int i=1;;i++) %hS|68pN6  
{ e'*HS7g  
String header=con.getHeaderFieldKey(i); Y qdWctUY  
if(header!=null) jjs&`Fy,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~!iQ6N?PY  
Utility.log(header+" : "+con.getHeaderField(header)); B/f0P(7  
else  }alj[)  
break; B1 0+*p(  
} #^#Kcg  
} I`RBj`IF  
klOp ^w  
rnFM/GAy  
public void splitterStop() kfb/n)b'  
{ ]DG?R68DQ  
bStop = true; }ucIH@U{  
} 9-1#( Y6S  
VaZn{z  
*O$CaAr\s  
} f|EUqu%E  
7v}x?I  
;^u*hZN[Up  
/* q z&+=d@  
**FileAccess.java t G.(flW,  
*//文件访问(定位,写) m4w ') r~  
package NetFox; )emOKS  
import java.io.*; F!!N9VIC  
o5o^TW{  
l3o#@sz:  
public class FileAccessI implements Serializable{ u0)7i.!M  
[dX`K`k  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z2c5m  
RandomAccessFile oSavedFile; M(q'%XL^  
long nPos; 4EP<tV  
DC+wD Bp;  
SS|z*h Z  
public FileAccessI() throws IOException ;oO v/3  
{ v`[Eb27W.  
this("",0); N^0uit  
} i8X`HbmN  
;Q0bT`/X  
=1;=  
public FileAccessI(String sName,long nPos) throws IOException @ez Tbc3  
{ K ?$#nt p  
oSavedFile = new RandomAccessFile(sName,"rw"); !<@J6??a}s  
this.nPos = nPos; ^nK7i[yF.k  
oSavedFile.seek(nPos); gYop--\14]  
} uwIc963  
.ae O}^  
Q/>L_S  
public synchronized int write(byte[] b,int nStart,int nLen) 2GmpCy`L"  
{ S]3Ev#>  
int n = -1; R\Z: n*  
try{ NF$\^WvYSP  
oSavedFile.write(b,nStart,nLen); N[|Nxm0z/C  
n = nLen; X~.f7Ao[  
} &xZyM@  
catch(IOException e) ~`#-d ^s:  
{ OK|qv[  
e.printStackTrace (); " K*  
} xFv;1Q  
JOn yrks  
4JIYbb-a'  
return n; lG<hlYckv  
} I,6/21kO  
p4u5mM  
"I- w  
} ,38Eq`5&W  
Tsb{25`+  
'fwU]Hm  
/* &sVvWNO#2  
**SiteInfoBean.java {Z;t ^:s#  
*/  @gGRm  
package NetFox; 6~meM@  
DrW#v-d  
?wpB`  
public class SiteInfoBean { VxO%rq3  
M.}7pJ7f  
#b0{#^S:  
private String sSiteURL; //Site's URL _1Z=q.sC  
private String sFilePath; //Saved File's Path lt'I,Xt  
private String sFileName; //Saved File's Name Eu<1Bse;  
private int nSplitter; //Count of Splited Downloading File Mq%,lJA\  
7YWNd^FI V  
HHk)ZfWRo  
public SiteInfoBean() ni&*E~a  
{//nSplitter的缺省值为5 6X g]/FD  
//default value of nSplitter is 5 }*U[>Z-eO  
this("","","",5); 2Nc>6  
} @{ ;XZb^  
:B *}^g  
uUR~&8ERX  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M<?Q4a'Q  
{ %%%fL;-y  
sSiteURL= sURL; uv{P,]lK  
sFilePath = sPath; Jc4L5*Xn/  
sFileName = sName; cX!Pz.C  
this.nSplitter = nSpiltter; XV>JD/K2  
YOyX[&oi  
rPzQ8<  
} sPAg)6&M  
0Rxe~n1o  
+m\|e{G  
public String getSSiteURL() }peBR80tQ  
{ [Bb utGvj  
return sSiteURL; 1MkI0OZE  
} J<j&;:IRd  
dpZ;l 9  
9$K;Raz%  
public void setSSiteURL(String value) ?0*8R K  
{ 9|' B9C  
sSiteURL = value; }71LLzG`/  
} /Poet%XvRx  
ZsP2>%"  
I XA>`D  
public String getSFilePath() (n( fI f  
{ ~!6K]hB4  
return sFilePath; JeH;v0  
} t/i5,le  
C2e.2)y  
%n0;[sD0A  
public void setSFilePath(String value) UnWW/]E  
{ a.F Al@Br  
sFilePath = value; )8gGv  
} sE(HZR1  
8Ad606  
%6j)=IOts  
public String getSFileName() Q<tu)Qo  
{ 4NEq$t$Jn  
return sFileName; zQy"m-Q  
} 3ucP(Ex@tg  
CCijf]+  
6w3R'\9  
public void setSFileName(String value) nHFrG =o,  
{ "LhUxnll  
sFileName = value; .o{0+fC#  
} 1tzV8(7  
pI`?(5iK6|  
}H:F< z*  
public int getNSplitter() z|R,&~:  
{ w [>;a.$  
return nSplitter; &YP#M |  
} #eP LOR&q  
 2B~wHv  
l kIn%=Z  
public void setNSplitter(int nCount) z5\;OLJS,  
{ -php6$|  
nSplitter = nCount; Ths_CKwgWY  
}  /RZR}  
} %9C@ Xl  
B=L&bx  
j '%4{n  
/* iItcN;;7  
**Utility.java 4\t1mocCSN  
*/ W~T}@T:EN  
package NetFox; #PvB/3  
! {,F~i9  
EC&@I+'8Q  
public class Utility { PrQ?PvA<L  
vEM(bT=H  
Zx }&c |Q  
public Utility() Z]w# vLR  
{ /h2b;"  
bte~c  
{'+Q H)w(  
} z"4]5&3A  
XK(`mEi  
//线程睡眠 +KGZ HO!  
public static void sleep(int nSecond) =]R3& ]#n  
{ 0X2@CPIFf  
try{ MWk:sBCqr  
Thread.sleep(nSecond); ;#GoGb4AM  
} jd`},X/  
catch(Exception e) S&C1TC  
{ X8eJ4%  
e.printStackTrace (); A?Qa 4i  
} GnXNCeE`  
} ivgpS5 M`Y  
vh!v MB}}  
//日志 wu<])&F  
public static void log(String sMsg) Bc-yxjsw  
{ SZ![%)83  
System.err.println(sMsg); S/vf'gj  
} v <\A%  
" }gVAAvc7  
q}uHFp/J  
public static void log(int sMsg) W_O)~u8  
{ +Z2MIC|Ud  
System.err.println(sMsg); 3 vP(S IF  
} 5M]z5}n/  
} {MAQ/5  
;32#t[i b  
Ax3W2s  
/* )Ag/Qep  
**TestMethod.java ( <t_Pru  
*/ 9ILIEm:  
package NetFox; tHD  
`;,Pb&W~  
p_*M:P1Ma4  
public class TestMethod { YO{GU7  
m^%|ZTrwN7  
?i\B^uB  
public TestMethod() M/PFPJ >`  
{ ///xx/weblogic60b2_win.exe 9n]|PEoAB  
try{ p5=|Y^g !  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?8dVH2W.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y< R=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PeX1wK%f  
fileFetch.start(); !2CL1j0(  
} $m1<i?'m  
catch(Exception e){e.printStackTrace ();} YIt9M,5/Q  
M x5`yT7  
%HQ.|  
} FFhtj(hVgc  
1 "TVRb  
=6FUNvP#8  
public static void main(String[] args) gV1[3dW  
{ ?71+ f{s  
new TestMethod(); (%CZ*L[9Z  
} Ph&urxH@  
} P27%xV-n>  
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