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http断点续传简单实现(java)

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/* x<%V&<z1g  
**SiteFileFetch.java mlD 1 o  
*/ +Tw]u`  
package NetFox;  <c &6M  
import java.io.*; Cs ND:m  
import java.net.*; `<:D.9vO "  
oH|<(8efD  
5E!G  
public class SiteFileFetch extends Thread { =whYo?cE(  
;<=B I!  
c _v;"QZ  
SiteInfoBean siteInfoBean = null; //文件信息Bean z_LN*u  
long[] nStartPos; //开始位置 (\M&Q-xZ  
long[] nEndPos; //结束位置 ,[{)4J$MV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 psZAO,p  
long nFileLength; //文件长度 9cm9;  
boolean bFirst = true; //是否第一次取文件 4/tp-dBip  
boolean bStop = false; //停止标志 +/E yX =  
File tmpFile; //文件下载的临时信息 KLn.vA.  
DataOutputStream output; //输出到文件的输出流 Tp7slKc0p  
BL^8gtdn  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Cg! ]x o  
public SiteFileFetch(SiteInfoBean bean) throws IOException p7pJ90~E  
{ ,y5 7tY  
siteInfoBean = bean; S EeDq/h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \%FEQa0u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); voHFU#Z$  
if(tmpFile.exists ()) WI$MT6  
{ *=X$j~#X  
bFirst = false; xC,;IS k,  
read_nPos();  :nHa-N3  
} &~xzp^&  
else 2-<i#nA3  
{ RN%*3{-  
nStartPos = new long[bean.getNSplitter()]; LZB=vc|3/  
nEndPos = new long[bean.getNSplitter()]; LPNJuz  
}  H?(I-vO  
fQ,L~:Y =  
L/VlmN_v>s  
o=1M<dL  
} 0;kp`hB  
^at X/  
7jZ=+2  
public void run() / ao|v  
{ @,Iyn<v{B  
//获得文件长度 kT+Idu  
//分割文件 8a^E{x@HT  
//实例FileSplitterFetch #0WGSIht<  
//启动FileSplitterFetch线程 vThK@P!s  
//等待子线程返回 i@C1}o-/  
try{ : ;nvqbd  
if(bFirst) g(i_di  
{ =wEqI)Td  
nFileLength = getFileSize(); I+?9}t  
if(nFileLength == -1) csPziH$wl  
{ H 40~i=.  
System.err.println("File Length is not known!"); BP6|^Q  
} #]iSh(|8  
else if(nFileLength == -2) 'V=i;2mB*  
{ Y'YvVI  
System.err.println("File is not access!"); DaV:Slp9  
} 8<Y*@1*j  
else 6,707h  
{ 6i6m*=h  
for(int i=0;i<nStartPos.length;i++) INd:_cT4l  
{ _7h:NLd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @MS}tZ5  
} _%xe:X+ M  
for(int i=0;i<nEndPos.length-1;i++) 9\_^"5l  
{ g/o@,_  
nEndPos = nStartPos[i+1]; B~[QmK  
} w&vZ$n-|  
nEndPos[nEndPos.length-1] = nFileLength; xH\#:DLY  
} [IF5Iv\b  
} , : I:F  
F ka^0  
3N(5V;ti  
//启动子线程 <}G*/ z?/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i;u#<y{E  
for(int i=0;i<nStartPos.length;i++) ~]MACG:'  
{ Ej\M e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \F$Vm'f_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9vQI ~rz?  
nStartPos,nEndPos,i); LFzL{rny!U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x6i7x"  
fileSplitterFetch.start(); #%~PNki  
} DLigpid  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @O!BQ^'hk#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |XDbf3^6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +b =X~>vZ  
nEndPos = " + nFileLength); Hwz.5hV"  
// fileSplitterFetch[nPos.length-1].start(); u<VR;p:y  
4"om;+\  
f,jN"  
//等待子线程结束 +N|}6e  
//int count = 0; p;y\%i_  
//是否结束while循环 :i?7RouO  
boolean breakWhile = false; ~ `xaBz0q  
,2|(UTv  
MO_-7,.y  
while(!bStop) c#ahFpsnlw  
{ 'n>v}__&|  
write_nPos(); ,ln=kj  
Utility.sleep(500); ]4uY<9VL  
breakWhile = true; 8|z@"b l)  
g< F7UA  
^$N}[1   
for(int i=0;i<nStartPos.length;i++) 0r=KY@D  
{ pie,^-_.g  
if(!fileSplitterFetch.bDownOver) CeZ+!-lG  
{ ujLz<5gKuO  
breakWhile = false; A-&'/IHR"B  
break; (GeOD V?U  
} \l_U+d,qq  
} qg`8f?  
if(breakWhile) W$>AK_Y}  
break; F[ '<;}  
?o D]J  
&OM e'P  
//count++; $:RP tG  
//if(count>4) < Z>p1S  
// siteStop(); -p-<mC@<&S  
} "PK`Ca@`v  
[X\<C '<  
URo#0fV4C  
System.err.println("文件下载结束!"); :L6,=#  
} IyV%tOy  
catch(Exception e){e.printStackTrace ();} k"L?("~   
} !eC]=PoY  
xoYaL  
)LdS1%  
//获得文件长度 q83!PI  
public long getFileSize() ] 'B4O1  
{ 0dKv%X#\  
int nFileLength = -1; \7d T]VV  
try{ C)RJjaOr  
URL url = new URL(siteInfoBean.getSSiteURL()); U9/>}Ni%3G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  {ch+G~oS  
httpConnection.setRequestProperty("User-Agent","NetFox"); B.oD9 <9  
Q+ogVvMq>  
%n!7'XF'[  
int responseCode=httpConnection.getResponseCode(); 6a%dq"5 +  
if(responseCode>=400) S#|dmg;p  
{ yQ/E0>Uj!  
processErrorCode(responseCode); ;+Mee ^E>!  
return -2; //-2 represent access is error dBG5IOD  
} KB\A<(o,  
F5(DA  
}R\;htmc;  
String sHeader; <`P7^ 'z!  
'k1vV  
m+LP5S  
for(int i=1;;i++) C"[d bh!  
{ p4sU:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZR |n\.  
//Utility.log(in.readLine()); :%2uZ/cG(  
sHeader=httpConnection.getHeaderFieldKey(i); 'X(Sn3  
if(sHeader!=null) 4^u wZ:  
{ `}o{o  
if(sHeader.equals("Content-Length")) |j w{7\+  
{ i[r>^U8O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6EY W:o  
break; |k [hk  
} 0\DlzIO  
} 8HxtmFqG  
else ^a #  
break; BqG7E t  
} U+7!Vpq  
} Cz)/Bq  
catch(IOException e){e.printStackTrace ();} FS^ie|8{D-  
catch(Exception e){e.printStackTrace ();} KpF/g[m  
5y8ajae:  
^>/] Qi  
Utility.log(nFileLength); /~6)Vt  
FXO{i:Zo  
nR#'BBlI  
return nFileLength; y-R:-K XH=  
} i0py5Q  
vIpitbFC  
"IMq +  
//保存下载信息(文件指针位置) vWq/A.  
private void write_nPos() ^oH!FN`;{  
{ D]B;5f  
try{ ~X2 cTG!,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^QbaMX  
output.writeInt(nStartPos.length); je`w$ ^w  
for(int i=0;i<nStartPos.length;i++) F0 ^kUyF|  
{ v#ERXIrf  
// output.writeLong(nPos); 0?/vcsO  
output.writeLong(fileSplitterFetch.nStartPos); ("T8mt[w>  
output.writeLong(fileSplitterFetch.nEndPos); 6SVh6o@]  
} iD`>Bt7gD  
output.close(); &8'QD~  
} ^,,lo<d_L  
catch(IOException e){e.printStackTrace ();} eczS(KoL4  
catch(Exception e){e.printStackTrace ();} -gR }^D   
} MB3 0.V/\  
,`.`}'  
b _%W*Q  
//读取保存的下载信息(文件指针位置) \L4+Dv<z  
private void read_nPos() <h[l)-86  
{ A;e0h)F$-  
try{ \h UE, ^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $,DX^I%!  
int nCount = input.readInt(); ~h@<14c{X  
nStartPos = new long[nCount]; f3M~2jbv'p  
nEndPos = new long[nCount]; ` 8OA:4).  
for(int i=0;i<nStartPos.length;i++) O}cg1Q8p  
{ xjO((JC  
nStartPos = input.readLong(); O({vHqN>  
nEndPos = input.readLong(); l! 9G  
} WlfS|/\%V^  
input.close(); BBUXoz  
} 97~*Z|#<+  
catch(IOException e){e.printStackTrace ();} Ii4lwZnz  
catch(Exception e){e.printStackTrace ();} dX>l"))yR  
} +pMjm&CF  
Bvy(vc=UDW  
"J(7fL$!  
private void processErrorCode(int nErrorCode) f7Fr%*cO  
{ 2O~I.(9(  
System.err.println("Error Code : " + nErrorCode); \/ 8 V|E  
} "Ca?liy  
_O*"_^6  
Tr@}  
//停止文件下载 K;}h u(*\]  
public void siteStop() <^,5z!z }  
{ k2S6 SB  
bStop = true; ?[K \X  
for(int i=0;i<nStartPos.length;i++) WF{rrU:  
fileSplitterFetch.splitterStop(); L8zY?v(bG  
3#@ETt0X(  
(!0=~x|Z[  
} WV'FW)%  
} Wi?37EHr  
//负责部分文件的抓取 '[h|f  
**FileSplitterFetch.java Jc:gNQCsP  
*/ 2nFSu9}+r  
package NetFox; 9rn[46s`  
JRC+>'}Xj  
!PzlrH)M=p  
import java.io.*; aiKZ$KLC  
import java.net.*; M)U 32gI:  
G^]7!:0  
4oF8F)ASj  
public class FileSplitterFetch extends Thread { 1o;+.]B  
P"<HxT?  
Ba\l`$%X  
String sURL; //File URL [Pu~kiN  
long nStartPos; //File Snippet Start Position }lk_Oe1  
long nEndPos; //File Snippet End Position /Wh} ;YTv^  
int nThreadID; //Thread's ID ^]$x/1I;  
boolean bDownOver = false; //Downing is over Q`Q%;%t  
boolean bStop = false; //Stop identical FX FTf2*T  
FileAccessI fileAccessI = null; //File Access interface 5Z7<X2  
wPn#>\/L  
;^Vsd\ac0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 24)3^1P\V  
{ ?dukK3u  
this.sURL = sURL; @}K'Ic  
this.nStartPos = nStart; -|MeC  
this.nEndPos = nEnd; n+M:0{Y|  
nThreadID = id; 8xQ5[Ov  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vMiZ:*iaj@  
} g3%Xh0007{  
!79^M  
,OX(z=i_  
public void run() IRemF@  
{ ZkW,  
while(nStartPos < nEndPos && !bStop) S;[*5g6a&x  
{ :!M/9D*}0  
-bo5/`x  
1Z?en  
try{ vr|9NP]v  
URL url = new URL(sURL); Tw< N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6uCa iPV  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,%#FK|  
String sProperty = "bytes="+nStartPos+"-"; 9pKN^FX,76  
httpConnection.setRequestProperty("RANGE",sProperty); J~6+zBF  
Utility.log(sProperty); fPf8hz>  
)z/+!y  
,BCtNt(  
InputStream input = httpConnection.getInputStream(); TC80nP   
//logResponseHead(httpConnection); >;eWgQ6V  
l+'@y (}Q  
MO+g*N  
byte[] b = new byte[1024]; XYtDovbv&  
int nRead; $DZ\61  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [];*9vxW  
{ QAigbSn]  
nStartPos += fileAccessI.write(b,0,nRead); #Jv|zf5Z  
//if(nThreadID == 1) :b[ [}'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _-$"F>  
} MzRws f  
LfEeFF=#n  
P08=?  
Utility.log("Thread " + nThreadID + " is over!"); 4k5X'&Q  
bDownOver = true; 'c3P3`o,;  
//nPos = fileAccessI.write (b,0,nRead); C fKvC  
} *2ZX*w37  
catch(Exception e){e.printStackTrace ();} Hn5:*;N  
} >M{=qs  
} n`Pwo &  
nqNL[w6{  
M=$ qus  
//打印回应的头信息 o(GXv3L  
public void logResponseHead(HttpURLConnection con) f]MKNX  
{ 1'or[Os3=  
for(int i=1;;i++) Q H:k5V~  
{ 8"L#5MO t  
String header=con.getHeaderFieldKey(i); BbEWa  
if(header!=null) q(sEN!^L`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1zwk0={x-%  
Utility.log(header+" : "+con.getHeaderField(header)); Gf'qPLK0  
else hh/C{ l  
break; 'NyIy:  
} | +osEHC  
} `)Z"||8K  
ocCq$%Ka  
ME"B1 Se\  
public void splitterStop() U.]5UP:a  
{ #=mLQSiQ  
bStop = true; K.s\xA5`_  
} u~WBu|  
Y 3W_Z  
5VD(fW[OW]  
} iV#sMJN9  
jFbj)!;  
<d89eV+  
/* Fk(nf9M%  
**FileAccess.java Y+vG ]?D  
*//文件访问(定位,写) t5: 1' N9P  
package NetFox; B:Y"X:Y  
import java.io.*; KE>|,U r  
jeb ]3i=pw  
Jbv66)0M  
public class FileAccessI implements Serializable{ &QHZ]2%U  
D d['e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (QS4<J"  
RandomAccessFile oSavedFile; ^pgVU&-~]/  
long nPos; KrVP#|9%"  
=.T50~+M  
ykAZP[^'  
public FileAccessI() throws IOException Ruy qB>[o  
{ %gBulvg  
this("",0); 2F5*C  
} dsJMhB_41U  
>3aB{[[N  
1ym^G0"s  
public FileAccessI(String sName,long nPos) throws IOException 7]\_7L|>]  
{ Xy(8}  
oSavedFile = new RandomAccessFile(sName,"rw"); 3|++2Z{},  
this.nPos = nPos; KZeaM  
oSavedFile.seek(nPos); vs=8x\W  
} iO$Z?Dyg9  
|q+3X)Y  
h"#[{$(  
public synchronized int write(byte[] b,int nStart,int nLen) ^@91BY  
{ "~V|p3  
int n = -1; <!qN<#$y  
try{ 2!@ER i  
oSavedFile.write(b,nStart,nLen); hCpX# rg?  
n = nLen; !H)Cua)  
} AFMIp^F  
catch(IOException e) oItEGJ|  
{ C!,|Wi2&  
e.printStackTrace (); qoZUX3{  
} FaA'%P@  
\d :AV(u  
]h3{M Tr/  
return n; cc0e(\  
} GkU]>8E'"  
"pA24Ze  
TyGsSc  
} v % c-El%  
qI= j>x  
V;N'?Gu  
/* F/ si =%  
**SiteInfoBean.java tNbL)  
*/ T[(4z@d`5  
package NetFox; ;NoD4*  
!C6[m1F  
W)LtnD2 w  
public class SiteInfoBean { sUe<21:  
RCC~#bb  
zZE@:P&lf  
private String sSiteURL; //Site's URL w~a_FGYX  
private String sFilePath; //Saved File's Path EJByYk   
private String sFileName; //Saved File's Name ^2f2g>9j_C  
private int nSplitter; //Count of Splited Downloading File nqv#?>Z^OT  
.9uw@ Eq  
Yn>y1~  
public SiteInfoBean() Y I?4e7Z+  
{//nSplitter的缺省值为5 SbYs a  
//default value of nSplitter is 5 -]Mbe2;  
this("","","",5); u27*-X 5  
} _mG>^QI.  
6 _n~E e  
&Jf67\N  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -. J@  
{ ?ISv|QpC  
sSiteURL= sURL; 6Gj69Lr  
sFilePath = sPath; ^v+7IFn  
sFileName = sName; &60#y4  
this.nSplitter = nSpiltter; O_^X:0}  
>XU93 )CX  
^2<nn op  
} dk@j!-q^  
g@s'-8}X^  
{!av3Pz\  
public String getSSiteURL() ) mG  
{ @7z_f!'u  
return sSiteURL; :/6gGU>pu  
} k<.VR"I p  
*#&s+h,^  
Z.{r%W{2  
public void setSSiteURL(String value) R2B0?fu  
{ 2nv-/ %]  
sSiteURL = value; _VFL}<i  
} D  Kng.P  
5Vu@gRk_  
-)o0P\cTEt  
public String getSFilePath() # fkOm Y7X  
{ k_A 9gj1  
return sFilePath; kFZjMchm A  
} 8pE0ANbq  
5;yVA  
*p>1s!i  
public void setSFilePath(String value) [*2|#KSCX  
{ qE)G;Y<,1  
sFilePath = value; "PtOe[Xk  
} f^D4aEU  
6H:'_|G  
?D]qw4J  
public String getSFileName() EC0M0qQ  
{ _>)=c<HL  
return sFileName; eK_Yt~dj  
} [-*8 S1  
OK1f Y`$z  
/`YbHYNF[  
public void setSFileName(String value) Z+J;nl  
{  U<Z\jT[  
sFileName = value; |&xjuBC  
} 1WbawiG}  
u9~RD  
q oJ4w7  
public int getNSplitter() YkqauyV^  
{ M!E#T-)  
return nSplitter; /naGn@m5u  
} 4t;m^Iv  
J&jNONu?  
!YJ^BI    
public void setNSplitter(int nCount) g bc])`aJ>  
{ TR([u  
nSplitter = nCount; i <%  
} }^/;8cfLY  
} . 7EZB  
<78LB/:  
7h3JH  
/* bAl0z)p  
**Utility.java 3ZKaqwK  
*/ 68v59)0U  
package NetFox; }{(|^s=  
9&t!U+  
hm5A@Z   
public class Utility { UIl^s8/  
8*V8B=q}K  
>5|;8v-r  
public Utility() VSI.c`=,  
{ M+N7JpR  
$CY B&|d  
)5M9Ro7  
} U2(|/M+  
jt/ |u=  
//线程睡眠 T'TxC)  
public static void sleep(int nSecond) J&IFn/JK$  
{ QhHexr6  
try{ cKj6tT"=O  
Thread.sleep(nSecond); fWBI}~e  
} A -dL_3  
catch(Exception e) &xwAE*}  
{ cP~?Iz8nD  
e.printStackTrace (); Cl+TjmOV\`  
} ]GS@ub  
} $K,6!FyBa  
FrNW@  
//日志 Kb#}f/  
public static void log(String sMsg) ]v^;]0vcr  
{ W,^(FR.  
System.err.println(sMsg); Va1 eG]jQ  
} EPz$`#Sh"  
Czs4jHTa`  
lj1wTiaI(  
public static void log(int sMsg) +c699j;[  
{ |x AwiF_  
System.err.println(sMsg); E!4Qc+.   
} g]g2`ab |  
} \sIRV}Tk}N  
V^t5 Y+7  
jaAv_=93f  
/* jG3}V3|.  
**TestMethod.java 2wWL]`(E  
*/ G~{xTpL  
package NetFox; I [J0r  
`O5kI#m)L*  
}[u9vZL  
public class TestMethod { |f^/((:D  
0 mWfR8h0  
m<BL/ 7  
public TestMethod() #lax0IYY=  
{ ///xx/weblogic60b2_win.exe >8 V;:(nt  
try{ W?"Z>tgp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FxKb  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?wps_XU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E\r5!45r  
fileFetch.start(); *|x2"?d-F:  
} 'nNw  
catch(Exception e){e.printStackTrace ();} |67j__XC  
*n0k2 p  
eBTy!!  
} UcMe("U  
-/aDq?<<  
VwoCR q*  
public static void main(String[] args) 5FHpJlFK,  
{ _[V.%k  
new TestMethod(); 0>-l {4srs  
} &b}!KD1  
} b9(d@2MtK  
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