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http断点续传简单实现(java)

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/* \Q$HXK  
**SiteFileFetch.java PgM(l3x  
*/ d=*x#In  
package NetFox; U Z_'><++  
import java.io.*; R*pC.QiB~  
import java.net.*; QfjN"25_  
H U+ I  
W !}{$  
public class SiteFileFetch extends Thread { B~o-l*  
_`-1aA&n~  
Y'VBz{brf  
SiteInfoBean siteInfoBean = null; //文件信息Bean njPPztv/@  
long[] nStartPos; //开始位置 ,YYVj{~2  
long[] nEndPos; //结束位置 2{,n_w?Wy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9SQ4cv*2  
long nFileLength; //文件长度 A=5epsB  
boolean bFirst = true; //是否第一次取文件 q%YV$$c   
boolean bStop = false; //停止标志 R,2P3lv1v@  
File tmpFile; //文件下载的临时信息 0ZpFE&  
DataOutputStream output; //输出到文件的输出流 CO+/.^s7}S  
6=hk=2]f  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) FqFapRX66Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException K*-@Q0"KM{  
{ $4SzUZ0  
siteInfoBean = bean; "Dcs])7Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8|?LN8rp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &^&zR(o`  
if(tmpFile.exists ()) +UN<Zp7I/  
{ ,3i,P(?(  
bFirst = false; ` Nh"  
read_nPos(); %qf  V+^  
} ef!XV7 P  
else {LzH&qu  
{ 7Z,opc  
nStartPos = new long[bean.getNSplitter()]; sM[I4 .A3  
nEndPos = new long[bean.getNSplitter()]; _6@hTen`  
} UaG1c%7?X  
3riw1r;Q  
n.oUVr=nX  
@F*wg  
} I751 t  
9Z"+?bv/  
"Ml&[O ge  
public void run() ykg#{9+  
{ bizTd  
//获得文件长度 #V02hs1  
//分割文件 D('2p8;2"7  
//实例FileSplitterFetch `?(Bt|<>  
//启动FileSplitterFetch线程 U5HKRO  
//等待子线程返回 SzD KByi  
try{ s) O[t  
if(bFirst) #EGA#SKoq  
{ /Dt d#OAdr  
nFileLength = getFileSize(); MTGiAFE  
if(nFileLength == -1) Ty(@+M~-  
{ 4674SzL  
System.err.println("File Length is not known!"); [Qt?W gPj  
} #L}+H!Myh  
else if(nFileLength == -2) V D?*h  
{ lfsqC};#\  
System.err.println("File is not access!"); HL3XyP7  
} &hIRd,1#  
else %6%<?jZ  
{ W/ay.I  
for(int i=0;i<nStartPos.length;i++) s?Uh|BfB  
{ r`S< A;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &ZHC-qMRK  
} )}%O>%  
for(int i=0;i<nEndPos.length-1;i++) wXjFLg!g?  
{ ^E`(*J/o  
nEndPos = nStartPos[i+1]; fQK"h  
} -~" :f8  
nEndPos[nEndPos.length-1] = nFileLength; nR>r2wMk@  
} X6+qpp  
} (UCK;k  
)+")Sz3zx  
5l-mW0,MK  
//启动子线程 ]j~"mFAP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^>y@4qB  
for(int i=0;i<nStartPos.length;i++) Z BUArIC  
{ sAJ7R(p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )&{K~i;:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lOwS&4UT  
nStartPos,nEndPos,i); R =Ws#'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y;?ie]3G  
fileSplitterFetch.start(); q}BzyC=:n  
} +z9@:L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %Pqk63QF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l=N2lHU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", raVA?|'g~  
nEndPos = " + nFileLength); D0(xNhmKz  
// fileSplitterFetch[nPos.length-1].start(); ;;$#)b  
C${ S^v  
'\fY<Q:!  
//等待子线程结束 %n%xR%|  
//int count = 0; PfS:AI y  
//是否结束while循环 tj]9~eJ-  
boolean breakWhile = false; ZlYPoOq  
Cd79 tu|  
;Yfv!\^|  
while(!bStop) -7uwOr  
{ [OTJVpC  
write_nPos(); b*fgv9Kh'  
Utility.sleep(500); lDC$F N  
breakWhile = true; R`";Z$~{  
;R=.iOn  
BG^C9*ZuP  
for(int i=0;i<nStartPos.length;i++) "1q>At  
{ $P7iRM]  
if(!fileSplitterFetch.bDownOver) j6~nE'sQ  
{ :M{Y,~cP  
breakWhile = false; qzw'zV  
break; !J*,)kRN  
} {HC@u{K -  
} %u^ JpC{E  
if(breakWhile) -5>-%13  
break; wfL-oi'5  
8E&XbqP+  
u JR%0E7!  
//count++; U`Jy!x2m  
//if(count>4) thO ~=RB  
// siteStop(); Ko&hj XHx  
} .I VlEG0  
3bqC\i^[\m  
N!Qg;(  
System.err.println("文件下载结束!"); WD;Y~|  
} z)XRx:YU;$  
catch(Exception e){e.printStackTrace ();} < _$%@4 L  
} FEPXuCb  
Glq85S  
]nQt>R p_  
//获得文件长度 r!P}u  
public long getFileSize() 2>-S-;i  
{ p2J|Hl|  
int nFileLength = -1; UY2X  
try{ $wYtyN[  
URL url = new URL(siteInfoBean.getSSiteURL()); {Y}dv`G#Iu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aw ?=hXR!  
httpConnection.setRequestProperty("User-Agent","NetFox"); =z{JgD/  
+5.t. d  
:0K8h  
int responseCode=httpConnection.getResponseCode(); E| YdcS  
if(responseCode>=400) ]Mj/&b>"e  
{ Sp}D ;7  
processErrorCode(responseCode); vhvdKD  
return -2; //-2 represent access is error vQF vtwd  
} GEjd7s]C  
VKm!Ri$  
FVv8--  
String sHeader; !|2VWI}  
.t&R>9cZ^  
M fk2mIy  
for(int i=1;;i++) T,fI BD:  
{ Tj~IaU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1[*UYcD  
//Utility.log(in.readLine()); *'"T$ib  
sHeader=httpConnection.getHeaderFieldKey(i); H4OhIxK  
if(sHeader!=null) T9 <2A1  
{ ,U*)2`[  
if(sHeader.equals("Content-Length")) Y=Z1Tdxa|  
{ 'tN25$=V&W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iDl;!b&V.  
break; AeIrr*~]B  
} Vh3Ijn  
} &Gm$:T'~  
else +,:^5{9{  
break; ?::NO Dg  
} w(L>#?  
} ^1:U'jIXO  
catch(IOException e){e.printStackTrace ();} oIGrA-T}  
catch(Exception e){e.printStackTrace ();} c/L>>t  
=H0vE7{*  
#{r#;+  
Utility.log(nFileLength); e@@?AB$n(  
A392=:N+Q  
%2'A pp  
return nFileLength; S1n3(U:m  
} j4FeSGa  
Lf:uNl*D  
oHM ]  
//保存下载信息(文件指针位置) *O:r7_ Y0  
private void write_nPos() :ztr)  
{ h@7FY  
try{ ?^' 7+8C*J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UE _fpq  
output.writeInt(nStartPos.length); dAP|:&y@  
for(int i=0;i<nStartPos.length;i++) 2LCB])X  
{ M)?dEgU}M  
// output.writeLong(nPos); ~mV"i7VX  
output.writeLong(fileSplitterFetch.nStartPos); g#NZ ,~  
output.writeLong(fileSplitterFetch.nEndPos); _a_xzv'  
} YL jHt\  
output.close(); H@X oqgI  
} _!xD8Di#  
catch(IOException e){e.printStackTrace ();}  gB\T[RV  
catch(Exception e){e.printStackTrace ();} UX`]k{Mz  
} EG'[`<*h  
-]C c  
gw+9x<e  
//读取保存的下载信息(文件指针位置) e73^#O&Xt  
private void read_nPos() d{et8N  
{ ogM%N  
try{ E{=2\Wkcp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _2fkb=2@  
int nCount = input.readInt(); 0,*%vG?Q  
nStartPos = new long[nCount]; qP!eJ6[Nh"  
nEndPos = new long[nCount]; P ]N [y  
for(int i=0;i<nStartPos.length;i++) Jxf~&!zR  
{ w)E@*h<Z  
nStartPos = input.readLong(); VS#wl|b8  
nEndPos = input.readLong(); QYXx:nIrg  
} I~PDaZP  
input.close(); B}OY /J/*8  
} Gx?+9C V  
catch(IOException e){e.printStackTrace ();} DPe]daF  
catch(Exception e){e.printStackTrace ();} ^x*nq3^h\  
} ?[ly`>KpJ  
D/(L  
RVtQ20e";r  
private void processErrorCode(int nErrorCode) -@^Zq}  
{ (VyNvB  
System.err.println("Error Code : " + nErrorCode); mtic>  
} U5Erm6U:  
Ot&:mT!2  
YF#H Sf7  
//停止文件下载 F0~k1TDw  
public void siteStop() g1(Xg.  
{ ]!1OH |Ad  
bStop = true; +ww^ev%  
for(int i=0;i<nStartPos.length;i++) ||2Q~*:  
fileSplitterFetch.splitterStop(); hf!|\f  
qv 3^5 d  
G DSfT{kK\  
} ,F+B Wot4  
} N;F)jO xsl  
//负责部分文件的抓取 \^+ILYO:$  
**FileSplitterFetch.java `|1MlRM9  
*/ ocwG7J\W  
package NetFox; N5|Rmfo1  
#)+- lPe  
fnzy5+9"  
import java.io.*; s*M@%_A?  
import java.net.*; 9D@$i<D:  
PDx)S7+w[  
fLN!EDq  
public class FileSplitterFetch extends Thread { ,Y_{L|:w  
C>^D*C(  
{ PlK@#UN  
String sURL; //File URL (%ew604X  
long nStartPos; //File Snippet Start Position X{Yw+F,j  
long nEndPos; //File Snippet End Position >QQ(m\a$  
int nThreadID; //Thread's ID KYJ1}5n  
boolean bDownOver = false; //Downing is over (lA.3 4.p  
boolean bStop = false; //Stop identical VCNT4m  
FileAccessI fileAccessI = null; //File Access interface Mro4`GL  
gLD`wfZR  
{!ZyCi19  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^jdL@#k00  
{ |wxGpBau  
this.sURL = sURL; ~KjJ\b)R  
this.nStartPos = nStart; ;:&?=d  
this.nEndPos = nEnd; ,reJ(s  
nThreadID = id; ~ <0Z>qr  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :L?_Y/K  
} FD7H@L5  
}pNX@C#De  
Ftb%{[0}u3  
public void run() P=AS>N^yaL  
{ $*MCU nl  
while(nStartPos < nEndPos && !bStop) 2)iD4G`  
{ uE_c4Hp  
ZU'!iU|8  
KV!<Oq  
try{ AWr}"r?s  
URL url = new URL(sURL); =Cf ]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); db=$zIB[:  
httpConnection.setRequestProperty("User-Agent","NetFox"); qG8s;_G  
String sProperty = "bytes="+nStartPos+"-"; r >{G`de4  
httpConnection.setRequestProperty("RANGE",sProperty); 0V,Nv9!S  
Utility.log(sProperty); )yee2(S  
Y,z??bm~J  
4 k}e28  
InputStream input = httpConnection.getInputStream(); -Q e~)7  
//logResponseHead(httpConnection); 4|J[Jdj  
; ~ 4k7Uz  
SDJH;c0   
byte[] b = new byte[1024]; Pd=,$UQp  
int nRead;  aA*9,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l4'~}nn(Y  
{ >}+Q:iNQ)2  
nStartPos += fileAccessI.write(b,0,nRead); f*((;*n ;  
//if(nThreadID == 1) hAR? t5c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S*W;%J5  
} 0O@_ cW  
n"{X!(RIcx  
kka"C]!  
Utility.log("Thread " + nThreadID + " is over!"); 7 &)]) {Q  
bDownOver = true; >O{7/)gS^  
//nPos = fileAccessI.write (b,0,nRead); #mc!Wt 10  
} % n$^-Vc&  
catch(Exception e){e.printStackTrace ();} {g F0Xm%  
}  <dR,'  
} 0`hwmDiB"  
[5ethM  
B:oF;~d/,  
//打印回应的头信息 I@7/jUO  
public void logResponseHead(HttpURLConnection con) r((Tavn  
{ _j#SpL'P  
for(int i=1;;i++) wvc>0?t'  
{ '8Wv.X0`  
String header=con.getHeaderFieldKey(i); _."E%|5  
if(header!=null) ,TC~~EWq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y>o>WN<q  
Utility.log(header+" : "+con.getHeaderField(header)); $%qg"  
else E{^^^"z P  
break; :xeLt;  
} *_hLD5K!  
} J%v5d*$.  
GG-[`!>.pw  
W?,$!]0  
public void splitterStop() W|c.l{A5Q  
{ gp  
bStop = true; 6v z1*\:H~  
} Q |hm1q  
-e>|kPfv!  
Agy <j   
} )^;DGzG  
L@)&vn]  
<)#kq1b?  
/* %]4-{%v  
**FileAccess.java \ElX~$fS  
*//文件访问(定位,写) O]=C#E{  
package NetFox; ?C;JJ#Ho  
import java.io.*; D[Iq n  
u}jrfKd E  
2"/yEg*=  
public class FileAccessI implements Serializable{ 7 ^I:=qc72  
ey1Z/|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5{l1A (b  
RandomAccessFile oSavedFile; :$H!@n*/R  
long nPos; k$[{n'\@  
'F_}xMU  
}=@zj6AC  
public FileAccessI() throws IOException D1"7s,Hmu  
{ /8eW@IO.F  
this("",0); C ?7X"~ ~  
} b~Z=:'m8  
D s-`  
y4F^|kS) [  
public FileAccessI(String sName,long nPos) throws IOException gg]~2f  
{ -J$g(sikt  
oSavedFile = new RandomAccessFile(sName,"rw"); 7kz-V.  
this.nPos = nPos; 960qvz!  
oSavedFile.seek(nPos); :m`/Q_y"  
} gue(C(~.k_  
1L[S*X  
MW@DXbKVl  
public synchronized int write(byte[] b,int nStart,int nLen) XVUf,N,  
{ N/{?7sG&  
int n = -1; -<oZ)OfU  
try{ 7:o+iP46  
oSavedFile.write(b,nStart,nLen); v]bAWo  
n = nLen; f=ib9WbR#  
} TETsg5#  
catch(IOException e) .hN3`>*V  
{ h~ha  
e.printStackTrace (); rSyaZ6#  
} zqGYOm$r  
|=3 *;}  
;nk@XFJ  
return n; |~NeB"l{  
} X <xqT  
878tI3-  
h)o]TV  
} u2lmwE  
FmA-OqEpA  
 c!D> {N  
/* Zr"dOj$Jf  
**SiteInfoBean.java (3fPt;U  
*/ v*D FiCQD  
package NetFox; T Nci.']  
*/U$sZQ)  
6y@<?08Q  
public class SiteInfoBean { iEhDaC[e(b  
Yq;&F0paK  
MVAc8dS  
private String sSiteURL; //Site's URL ,k%8yK  
private String sFilePath; //Saved File's Path '3%*U*I  
private String sFileName; //Saved File's Name Oxn'bh6R0  
private int nSplitter; //Count of Splited Downloading File 4TJ!jDkox  
r,nn~  
,4Y sZ  
public SiteInfoBean() 1UyH0`&  
{//nSplitter的缺省值为5 CjZ6NAHc  
//default value of nSplitter is 5 '#f?#(  
this("","","",5); ~~dfpW_"  
} IMR$x(g= F  
nO [QcOf  
nDn{zea7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KgU[  
{ j?J=w=.Nx  
sSiteURL= sURL; ^K>pT}u  
sFilePath = sPath; Na;t#,  
sFileName = sName; N[{]iQ  
this.nSplitter = nSpiltter; D[W}[r  
2$Y3[$  
K!b>TICa:  
} 6cZ  C  
"0Y&~q[=  
"GBUQ}  
public String getSSiteURL() g{&PrE'e9  
{ QQ|9>QP  
return sSiteURL; ;S =e%:zb  
} A'v[SUW'm  
_Fvsi3d/  
XAlD ww  
public void setSSiteURL(String value) EM~7#Y  
{ e)og4  
sSiteURL = value; % NwoU%q  
} Ug `   
%J3lK]bv(  
A3!2"}L  
public String getSFilePath() $YR{f[+L w  
{ oG9SO^v_  
return sFilePath; D2-O7e  
} <v-92?  
"lb\c  
&:,fb]p  
public void setSFilePath(String value) dW6Q)Rfi  
{ "p2u+ 8?  
sFilePath = value; KK MWD\  
} n]Ebwznt-  
-*5yY#fw}  
C890+(D~  
public String getSFileName() E<P*QZ-C3  
{ 4t(QvIydA  
return sFileName; F6h/0i  
} 0MhxFoFO  
J2x$uO{Bn  
c{ZqQtfM  
public void setSFileName(String value) :4b- sg#  
{ m R"9&wq  
sFileName = value; ]n/jJ_[  
} m';|}z'  
JCBnFrP  
,9+nfj  
public int getNSplitter() *+# k{D,  
{ T)*l' g'  
return nSplitter; %hrsE5k^,  
} RH1U_gp4 ]  
KN|'|2/|  
9yp^zL  
public void setNSplitter(int nCount) EzwF`3RjK  
{ aw;{<?*  
nSplitter = nCount; ZW`HDrP`  
} LIc*tsl  
} F\l!A'Q+t  
ZlUFJ*pk  
I\)N\mov e  
/* +# A|Zp<  
**Utility.java jh-kCF  
*/ mRNHq3  
package NetFox; "otr+.{`*  
FkLQBpp(x  
O{O 9}]6  
public class Utility { 7Co3P@@  
6YB-}>?  
~6=Wq64  
public Utility() %,h!: Ec^c  
{ ~p0 e=u  
E%KC'T N^D  
1"N/ZKF-x  
} 30:HRF(:  
6!i( \Q*  
//线程睡眠 h/w]  
public static void sleep(int nSecond) 4ZSfz#<[z  
{ K4BTk !  
try{ iFXUKGiV  
Thread.sleep(nSecond); 4d,qXSKty  
} h:eN>yW  
catch(Exception e) qLU15cOM  
{ Ul7,k\q@  
e.printStackTrace ();  ||bA  
} 3ytx"=B%  
} 5QCw5N  
F^J&g%ql  
//日志 0f EZD$  
public static void log(String sMsg) xow6@M,  
{ dpl"}+  
System.err.println(sMsg); Vu^Q4Z  
} 2*b# +b  
!^rITiy  
gt(X!iN]  
public static void log(int sMsg) Ss*Lg K_  
{ R A-^!4tX  
System.err.println(sMsg); ~M|NzK_9  
} 89?3,k  
} `XFX`1  
=+kvL2nx-  
HQ jxJd5P  
/* _CYmG"mY  
**TestMethod.java Y,p2eAss  
*/ exGhkt~  
package NetFox; +sV#Z,  
4'7 v!I9  
#w[q.+A  
public class TestMethod { _Y:Ja0,  
+Px<DX+  
U:C-\ M  
public TestMethod() fbW,0  
{ ///xx/weblogic60b2_win.exe woC FN1W  
try{ mRix0XBI~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z)b)v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?et0W|^k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); OdtbVF~  
fileFetch.start(); !ds"88:5^  
} 1VPfa  
catch(Exception e){e.printStackTrace ();} t/EMBfLc  
o)$Q]N##  
tOp:e KN  
} ZKiL-^dob  
N69eI dl  
"m<eHz]D  
public static void main(String[] args) FN8=YUYK%  
{ o>QFd x  
new TestMethod(); DT1i2!  
} Gff[c%I  
} ;8 /+wBnm  
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