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http断点续传简单实现(java)

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/* #_wq#rF  
**SiteFileFetch.java ,|({[ 9jA  
*/ lb-1z]YwQ  
package NetFox; l?U=s7s0?  
import java.io.*; bx8](cT_  
import java.net.*; 4VwF \  
&vp KBR ^  
\g39>;iR  
public class SiteFileFetch extends Thread { MIrx,d  
rGyAzL]  
{_O!mI*  
SiteInfoBean siteInfoBean = null; //文件信息Bean "d_wu#fO)  
long[] nStartPos; //开始位置 H4w\e#|  
long[] nEndPos; //结束位置 k2U*dn"9U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?BnU0R_r]  
long nFileLength; //文件长度 (j&:  
boolean bFirst = true; //是否第一次取文件 \!-BR0+y;  
boolean bStop = false; //停止标志 "+F'WCJ-(*  
File tmpFile; //文件下载的临时信息 y>P+"Z.K%}  
DataOutputStream output; //输出到文件的输出流 $oK&k}Q  
*|fF;-#v  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +(3_V$|Dv  
public SiteFileFetch(SiteInfoBean bean) throws IOException ::|~tLFu  
{ qz-QVY,  
siteInfoBean = bean; 2X?GEO]/4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KUAzJ[>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j~Aq-8R=  
if(tmpFile.exists ()) d#g))f;  
{ w7V\_^&Id  
bFirst = false; 7Q}pKq]P  
read_nPos(); sS>b}u+v#!  
} %c }V/v_h  
else pjWRd_h.  
{ %=`JWLLG  
nStartPos = new long[bean.getNSplitter()]; kJWg},-\  
nEndPos = new long[bean.getNSplitter()]; 7>JTQ CJ  
} d~LoHp  
Xu]~vik  
2?JV "O=  
.A2$C|a*  
} =&WIa#!=  
'a ['lF  
5?kfE  
public void run() Jj"{C]  
{ {>f"&I<xw  
//获得文件长度 1@F-t94I  
//分割文件 ju"z  
//实例FileSplitterFetch HL38iXQ( 3  
//启动FileSplitterFetch线程 h: ' |)O  
//等待子线程返回 #Iw(+%D  
try{ g4IF~\QRVi  
if(bFirst) lB,1dw2(T  
{ e8F]m`{_"  
nFileLength = getFileSize(); Y2u\~.;oq  
if(nFileLength == -1) CL=%eSsuD  
{ bn(N8MFCV  
System.err.println("File Length is not known!"); [n2B6Px  
} m8q4t ,<J  
else if(nFileLength == -2) va6Fp2n<1*  
{ .uuhoqG0  
System.err.println("File is not access!"); EuK}L[Kl  
} b3ohTmy4(  
else YV O$`W^N  
{ j9p6 rD  
for(int i=0;i<nStartPos.length;i++) #De>EQ%  
{ x[(6V'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?b (iWq  
} !+GYu;_  
for(int i=0;i<nEndPos.length-1;i++) T8XrmR&?PX  
{ C= ~c`V5>r  
nEndPos = nStartPos[i+1]; tn]nl!_@  
} U'fP  
nEndPos[nEndPos.length-1] = nFileLength; 7'G;ijx  
} J2bvHxb Rd  
} j#l=%H  
X3.zNHN5  
0a~t  
//启动子线程 nf.Ox.kM)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -@pjEI  
for(int i=0;i<nStartPos.length;i++) cHjQwl  
{ )PX VR T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -'! J?~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 77P\:xc  
nStartPos,nEndPos,i); <J/ =$u/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ma.84~m  
fileSplitterFetch.start(); i?x gV_q;  
} mMAN* }`O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I |Oco?Q"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }Q\%tZC#T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q~ H>rC(\  
nEndPos = " + nFileLength); x/*lNG/  
// fileSplitterFetch[nPos.length-1].start(); oz) [ -  
"H-s_Y#  
dljE.peL  
//等待子线程结束 3:)z+#Uk6  
//int count = 0; ARKM[]  
//是否结束while循环 2|nm> 4  
boolean breakWhile = false; @N=vmtLP  
hFrMOc&  
"-~ 7lY%  
while(!bStop) |5&+VI  
{ kwI``7g8*e  
write_nPos(); >Bt82ibN  
Utility.sleep(500); 1[FN: hm  
breakWhile = true; 5^B79A"}  
nV' 1 $L#  
O2w-nd74U  
for(int i=0;i<nStartPos.length;i++) zF1!a  
{ Abc{<4 z0?  
if(!fileSplitterFetch.bDownOver) [9m3@Yd'  
{ AGlBvRX7e  
breakWhile = false; G@]3EP  
break; Hfcpqa  
} oaIk1U;g  
} ~k"+5bHa*  
if(breakWhile) '6so(>|  
break; g'"~'  
LrB 0x>  
x~5uc$  
//count++; R~vGaxZ$  
//if(count>4) ~Amq1KU*Z  
// siteStop(); BoD{fg  
} 2HX/@ERhmu  
-l^<[%  
j*{0<hZb}  
System.err.println("文件下载结束!"); !~ox;I}S  
} ;Afz`Se1@  
catch(Exception e){e.printStackTrace ();} p~D}Iyww1_  
} djd/QAfSC  
PDNl]?  
VYk:c`E  
//获得文件长度 J9^NHU  
public long getFileSize() ]Q^)9uE\D  
{ Cf% qap#  
int nFileLength = -1; YT\`R  
try{ U3(+8}Q  
URL url = new URL(siteInfoBean.getSSiteURL()); =[B\50]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I/E9:  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7^L  
) .~ "  
Kk3+ ]W<  
int responseCode=httpConnection.getResponseCode(); p3s i\Fm!  
if(responseCode>=400) V9c.(QY|f  
{ <c+.%ka  
processErrorCode(responseCode); 1`cH EAa  
return -2; //-2 represent access is error 2t= = <x  
} s9 - qR_  
ejN/U{)jK'  
9`in r.:  
String sHeader; .#[ 9q-  
N} EKV  
O]N/(pe:d  
for(int i=1;;i++) %a%xUce&-X  
{ |]\zlH"w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fY<#KM6X  
//Utility.log(in.readLine()); AwM`[`ReE  
sHeader=httpConnection.getHeaderFieldKey(i); `7 "="T~ *  
if(sHeader!=null) q lc@$  
{ !eX0Q 2  
if(sHeader.equals("Content-Length")) CPz<iU  
{ ?ZF):}r vZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ailq,  c  
break; Qqm?%7A1  
} C}huU  
} sf*4|P}  
else LrU8!r`a  
break; !=0h*=NOYt  
} L\Se ,  
} lY%I("2=  
catch(IOException e){e.printStackTrace ();} N>mW64_H)  
catch(Exception e){e.printStackTrace ();} .j}]J:{%  
(x=$b(I  
7KC>?F  
Utility.log(nFileLength); RQVu~7d[  
3j7FG%\  
e@D_0OZ  
return nFileLength; '| 8 dt "C  
} <jh4P!\&j  
: auR0FE  
*`>BOl+ro  
//保存下载信息(文件指针位置) k^5Lv#Z  
private void write_nPos() J1w;m/oV  
{ /\mtCa.O  
try{ jJ$\WUQ.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QiK>]xJ'  
output.writeInt(nStartPos.length); qTsy'y;Z  
for(int i=0;i<nStartPos.length;i++) f$I=o N  
{ { I#>6  
// output.writeLong(nPos); 65EMB%  
output.writeLong(fileSplitterFetch.nStartPos); 0 QTI;3  
output.writeLong(fileSplitterFetch.nEndPos); O( ^h_  
} rT2Njy1  
output.close(); xo>0j#  
} JP#S/kJ%3  
catch(IOException e){e.printStackTrace ();} ,54z9F`  
catch(Exception e){e.printStackTrace ();} EU[\D;  
} Gwd38  
.}IW!$ dq  
O}M-6!%<,  
//读取保存的下载信息(文件指针位置) +,e#uuj$p  
private void read_nPos() Xa[k=qFo  
{ =j.TDv'^nd  
try{ t3<MoDe7`r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3$?6rMl@y  
int nCount = input.readInt(); cBxGGggB  
nStartPos = new long[nCount]; O<S.fr,  
nEndPos = new long[nCount]; #&Hi0..y  
for(int i=0;i<nStartPos.length;i++) IuwE&#  
{ !"^Zr]Qt+\  
nStartPos = input.readLong(); vJWBr:`L  
nEndPos = input.readLong(); s9Hxiw@D  
} y:'Ns$+  
input.close(); 1wFu3fh@  
} "i0>>@NR'  
catch(IOException e){e.printStackTrace ();} CsZ~LQ=DB  
catch(Exception e){e.printStackTrace ();} s6H.Q$3L  
} y4-kuMYR  
B;k'J:-"  
Q'OtXs 80  
private void processErrorCode(int nErrorCode) QjTSbHtH  
{ /U;j-m&   
System.err.println("Error Code : " + nErrorCode); ]az(w&vqg2  
} IkCuw./  
"6B@V=d  
%8*:VR  
//停止文件下载 PaCC UF  
public void siteStop() BA@E  
{ / VYT](  
bStop = true; "&6vFmr  
for(int i=0;i<nStartPos.length;i++) ^/C\:hw  
fileSplitterFetch.splitterStop(); eF+F"|1h  
'f( CN3.!  
q5;dQ8Y ?  
} eHr0],  
} b A+_/1C  
//负责部分文件的抓取 $Q*R/MY  
**FileSplitterFetch.java 7zu\tCWb  
*/ ]8A*uyi  
package NetFox; `~XksyT  
}e\"VhAl/  
2!#g\"  
import java.io.*; o/Ismg-p  
import java.net.*; 'z|Da&d P  
UoxlEec  
g5y+F]'I  
public class FileSplitterFetch extends Thread { Z^kE]Ir#EV  
M@[W"f Wq  
6KddHyFz  
String sURL; //File URL Ci`o;KVj  
long nStartPos; //File Snippet Start Position f@i#Znkf*?  
long nEndPos; //File Snippet End Position n0KpKH<&  
int nThreadID; //Thread's ID ,L& yKS@  
boolean bDownOver = false; //Downing is over KA2>[x2  
boolean bStop = false; //Stop identical eoiz]L  
FileAccessI fileAccessI = null; //File Access interface 5,Fq:j)MxW  
aC1z.?!U  
(L(7)WbH  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OxHcoNrz  
{ -06G.;W\^  
this.sURL = sURL; Bsa;,  
this.nStartPos = nStart; NBk0P*SI  
this.nEndPos = nEnd; ~4 fE`-O  
nThreadID = id; [Hh*lKg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iT'doF  
} bdL= ?KS  
VhO+nvd*W  
^yW['H6V  
public void run() S~/2Bw!2  
{ :E9pdx+  
while(nStartPos < nEndPos && !bStop) /EjXyrn2  
{ )Rn\6ka  
gX" -3w  
\c2x udU  
try{ #D9.A7fCc5  
URL url = new URL(sURL); \,13mB6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '8 .JnCg  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2M x\D  
String sProperty = "bytes="+nStartPos+"-"; k[f2`o=  
httpConnection.setRequestProperty("RANGE",sProperty); f&<+45JI  
Utility.log(sProperty); R+HX'W  
]'5Xjcx  
KElEGW  
InputStream input = httpConnection.getInputStream(); L-9fo-  
//logResponseHead(httpConnection); CcQc!`YC  
ny KfM5s_  
Z@s[8wrmPl  
byte[] b = new byte[1024]; w"{DLN[Qw  
int nRead; Va )W[I  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %`i*SF(gV  
{ 8\s#law  
nStartPos += fileAccessI.write(b,0,nRead); p7QZn.,=u  
//if(nThreadID == 1) /?;'y,(Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fXMY.X>f  
} |OeWM  
Gazva/e  
v>keZZOs  
Utility.log("Thread " + nThreadID + " is over!"); yksnsHs}d  
bDownOver = true; NgTB4I 8P  
//nPos = fileAccessI.write (b,0,nRead); +,,(8=5 g  
} /4T6Z[=s  
catch(Exception e){e.printStackTrace ();} @T^FOTW  
} xX-r<:'tmi  
} Krae^z9R  
Ao\P|K9MyL  
%,WH*")  
//打印回应的头信息 GL?b!4xx  
public void logResponseHead(HttpURLConnection con) @)d_zWE  
{ LK DfV  
for(int i=1;;i++)  .2&L.  
{ p3vf7eqn  
String header=con.getHeaderFieldKey(i); W5Jw^,iPd  
if(header!=null) #1-WiweO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K 4GuOl  
Utility.log(header+" : "+con.getHeaderField(header)); o8X_uKEI  
else _0+X32HjJ  
break; GST#b6S  
} @_kF&~  
} x3i}IC  
lpXGsK H2  
hJ(vDv%  
public void splitterStop() Z[Tou  
{ u\Cf@}5(  
bStop = true; j&X&&=   
} ^=eC1 bQA  
u)<]Pb})r  
D% jGK  
} G4'Ia$  
pa46,q&M  
x`g,>>&C  
/* $z[S0Cm  
**FileAccess.java +(2$YJ35  
*//文件访问(定位,写) 'i%r  
package NetFox; J$}]p  
import java.io.*; m\qeYI6,Z  
Gko"iO#  
l:'#pZ4T  
public class FileAccessI implements Serializable{ 0!,uo\`  
=.z;:0]'n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Wxj_DTi[1"  
RandomAccessFile oSavedFile; bL xZ 5C7t  
long nPos; %M`48TW)  
"}v.>L<P  
5QiQDQT}5  
public FileAccessI() throws IOException !'H$08Ql}  
{ hdDT'+  
this("",0); '4uu@?!dVk  
} i2Wvu3,D3-  
c*rH^Nz  
@Fc:9a@  
public FileAccessI(String sName,long nPos) throws IOException US$$ADq  
{ @dv8 F "v  
oSavedFile = new RandomAccessFile(sName,"rw"); ?JZ$M  
this.nPos = nPos; >eA@s}_8  
oSavedFile.seek(nPos); Wh i#Ii~  
} %[|^7  
&:l-;7d  
`rVru= zoy  
public synchronized int write(byte[] b,int nStart,int nLen) d/R!x{$-f  
{ E[t0b5h  
int n = -1; s $Vv  
try{ }. &ellNQ  
oSavedFile.write(b,nStart,nLen);  U${W3Ra  
n = nLen; hnFpC1TO  
} {A/^;X{N^  
catch(IOException e) 8;?4rrS  
{ e ymv/  
e.printStackTrace (); p XXf5adl<  
} zx%WV@O9  
V<UChD)N`  
J'Pyn  
return n; vS\2zwb}  
} yD~,+}0)  
$6Q^u r:  
mcQL>7ts  
} VaD+:b4  
XSC=qg$  
qS\#MMsTd  
/* kL1<H%1'  
**SiteInfoBean.java ?5EH/yV;  
*/ =|-= 4.b+|  
package NetFox; l^&#9d  
B,\VLX  
t}eyfflZ  
public class SiteInfoBean { %]Z4b;W[Y  
K ~mUO  
aG]>{(~cL  
private String sSiteURL; //Site's URL pA*C|g  
private String sFilePath; //Saved File's Path ]P3m=/w  
private String sFileName; //Saved File's Name 12lX-~[["  
private int nSplitter; //Count of Splited Downloading File l$/pp  
$ztsbV}  
v\,N"X(,  
public SiteInfoBean() E<\$3G-do  
{//nSplitter的缺省值为5 bq ED5;d'#  
//default value of nSplitter is 5 nx'c=gp  
this("","","",5); O=3/ qs6m  
} \I!mzo  
0 cycnOd  
m}'_Poc  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XX/gS=NE#.  
{ \Sd8PGl*'  
sSiteURL= sURL; H<Sf0>OA  
sFilePath = sPath; (1'DZ xJ&u  
sFileName = sName; i"G'#n~e  
this.nSplitter = nSpiltter; gNEcE9y 2  
{K.H09Y  
F(hPF6Zx(  
} R `tJ7MB  
3Cj)upc  
>IIq_6Z#  
public String getSSiteURL() To*+Z3Wd  
{ S[K5ofV  
return sSiteURL; p{L;)WTI  
} 1*8;)#%&  
cp@Fj"  
$/M-@3wro  
public void setSSiteURL(String value) j+h+Y|4J  
{ hty'L61\z  
sSiteURL = value; fLe~X!#HF  
} Z oXz@/T  
z&gma Ywq  
(S!UnBb&  
public String getSFilePath() `2 <:$]  
{ itzUq,T  
return sFilePath; FC1rwXL(  
} jUm-!SK}q  
.rK0C)  
geR :FO;\  
public void setSFilePath(String value) yq-~5ui  
{ E /H%q|q  
sFilePath = value; %NQ%6 B  
} ,LA'^I?  
<uuumi-!%G  
NwF"Zh5eMW  
public String getSFileName() Be|! S_Y P  
{ 6RbDc *  
return sFileName; Qbv@}[f  
} =c@hE'{  
4fKvB@O@.  
9;L4\  
public void setSFileName(String value) ;3/}"yG<p  
{ ^i8,9T'=  
sFileName = value; q8$t4_pF  
}  NAD^10  
1)= H2n4)  
y8$3kXh  
public int getNSplitter() |1%% c %  
{ t+KW=eW  
return nSplitter; %!\=$s}g  
} 5b:1+5iF-  
?V2P]|  
9&* 7+!  
public void setNSplitter(int nCount) L"'=[O~  
{ -4x! #|]  
nSplitter = nCount; &`qYe)1Eo  
} TAUl{??,  
} 4+hNP'e  
aA4RC0'  
iAH,f5T  
/* [k$GUU,jY  
**Utility.java lW c[Q1  
*/ ~Fb@E0 }!  
package NetFox; |X=p`iz1&  
rpiuFst  
QKP #wR  
public class Utility { =wX;OK|U(^  
9CS" s_  
1e[?}q]*  
public Utility() t#.}0Te7  
{ \r IOnZ.WK  
Hpix:To  
+1wEoU.l2  
} n=-vOa%  
(LK@w9)i;  
//线程睡眠 !U?C _  
public static void sleep(int nSecond) Y)k"KRW+  
{ !ldEy#"X  
try{ Q qF<HCO  
Thread.sleep(nSecond); V30w`\1A  
} igQzL*X  
catch(Exception e) j(y<oxh  
{ #MY oy7=  
e.printStackTrace (); i]<@  
} GgE g(AT  
}  z/91v#}.  
yr+QV:oVA  
//日志 zmQQ/ 7K  
public static void log(String sMsg) 8(n>99 VVK  
{ 'ij+MU 1  
System.err.println(sMsg); ,IhQ%)l  
} cy@oAoBq  
)$p36dWl  
# fF5O2E'3  
public static void log(int sMsg) ?xwi2<zz  
{ y" H5>  
System.err.println(sMsg); .*N,x(V  
} }uMu8)Q  
} =EVB?k ,  
OF*E1B M  
o%Q9]=%!  
/* R7IFlQH%  
**TestMethod.java s[7$%|~W  
*/ h*^JFZb  
package NetFox; b6S"&hs  
ozsd6&z5l  
iJh{ ,0))g  
public class TestMethod { `}t5`:#k  
"zw{m+7f,  
]iTP5~8U  
public TestMethod() O)^F z:  
{ ///xx/weblogic60b2_win.exe kR1 12J9P  
try{ ]foS.D,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,sj(g/hg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c k[uvH   
SiteFileFetch fileFetch = new SiteFileFetch(bean); `%|3c  
fileFetch.start(); 1?)h-aN  
} .K^gh$z!  
catch(Exception e){e.printStackTrace ();} q>%.zc[x  
rui 8x4c  
'\QJ{/JV  
} :JBt qpo2  
j 7);N  
[|$C2Dhw=  
public static void main(String[] args) GF@` ~im  
{ ug}u>vQ>  
new TestMethod(); IHW s<U  
} sz%]rN6$  
} 4NRj>y  
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