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http断点续传简单实现(java)

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/* oZmni9*SD  
**SiteFileFetch.java &xj?MgdNL  
*/ RoJ{ ou@cs  
package NetFox; &`Z>zT}  
import java.io.*; w6qx  
import java.net.*; rKg5?.  
<Ktx*(D  
Hb#8?{  
public class SiteFileFetch extends Thread { Mf<P ms\F  
|jU/R  
egYJ.ZzF0  
SiteInfoBean siteInfoBean = null; //文件信息Bean b=wc-n A  
long[] nStartPos; //开始位置 rMH\;\ I|U  
long[] nEndPos; //结束位置 GW]Ygf1t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K`M8[ %S  
long nFileLength; //文件长度 @@# ^G8+l  
boolean bFirst = true; //是否第一次取文件 ]pzf{8%  
boolean bStop = false; //停止标志 f]qP xRw  
File tmpFile; //文件下载的临时信息 2pQ zT  
DataOutputStream output; //输出到文件的输出流 38 tRb"3zP  
6*lTur9ni  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) lN<vu#  
public SiteFileFetch(SiteInfoBean bean) throws IOException TXv3@/>ZlG  
{ ~N;kF.q&>&  
siteInfoBean = bean; ry*b"SO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'Wn'BRXq3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fx_7X15  
if(tmpFile.exists ()) VEkv JX.  
{ _<+!  
bFirst = false; G yvEc3|@  
read_nPos(); x<>#G~-  
} ]L"jt8E  
else Xat>d>nJ]  
{ &_x:+{06  
nStartPos = new long[bean.getNSplitter()]; ^{T]sv  
nEndPos = new long[bean.getNSplitter()]; }:])1!a  
} ;/XWX$G@  
Q;*TnVbJ  
S4n\<+dR<  
`%ZM(9T  
} 2TXrVaM  
u<!8dQ8  
4[44Eku\  
public void run() _s[ohMlh  
{ _U?   
//获得文件长度 |e!%6Qq3  
//分割文件 `WboM\u  
//实例FileSplitterFetch Rp^k D ,*  
//启动FileSplitterFetch线程 h#dp_#  
//等待子线程返回 ]o$aGrZ  
try{ }Y[xj{2$O  
if(bFirst)  TTZb.  
{ C*a>B,H  
nFileLength = getFileSize(); ]u?|3y^ (  
if(nFileLength == -1) v,I4ozDx  
{ ve49m%NQ  
System.err.println("File Length is not known!"); bJ4})P&  
} E z?O gE{  
else if(nFileLength == -2) I q]+O Q  
{ 3+%a  
System.err.println("File is not access!"); S1p 4.qJ  
} [_Fj2nb*  
else 0Dv r:]R  
{ dY5 m) ?  
for(int i=0;i<nStartPos.length;i++) uZL,+Ce|  
{ E#[_"^n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2F%2K?$`Ej  
} }F!tM"X\  
for(int i=0;i<nEndPos.length-1;i++) *|{1`{8n  
{ h6Ovl  
nEndPos = nStartPos[i+1]; }`ox;Q  
} Z@2^> eC  
nEndPos[nEndPos.length-1] = nFileLength; Xia4I* *  
} R.@I}>  
} wW EnAW~  
 Gf_Je   
Q"7vzri  
//启动子线程 Rsd~t_a1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |(u6xPs;P  
for(int i=0;i<nStartPos.length;i++) <|8N\FU{  
{ 1Bp?HyCR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), td JA?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *eL&fC  
nStartPos,nEndPos,i); @rI+.X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "A\h+q-  
fileSplitterFetch.start(); @( p9}  
} 5,  "  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6l]jm j)/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +-~8t^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1[p6v4qO{  
nEndPos = " + nFileLength); Nk?eVJ)  
// fileSplitterFetch[nPos.length-1].start(); 0Lb:N]5m8  
o|(Ivt7jk  
Vl'Gi44)3"  
//等待子线程结束 H c,e&R  
//int count = 0; w_qX~d/  
//是否结束while循环 V1di#i:  
boolean breakWhile = false; o-i9 :AHs  
AK$&'t+$}7  
*ThP->&:(  
while(!bStop) 4FQB%3>*  
{ @=r YOQj |  
write_nPos(); NW_i<#  
Utility.sleep(500); 0RFBun{  
breakWhile = true; $-Iui0h  
n=Ze p{^  
JOwm|%>3a  
for(int i=0;i<nStartPos.length;i++) D[/h7Ha  
{ X'FDQoH  
if(!fileSplitterFetch.bDownOver) C- 5QhD  
{ !=Scpo_  
breakWhile = false; Qe4O N3X!  
break; wtM1gYl^  
} 3qf?n5 "8  
} 41uiW,  
if(breakWhile) #mKF)W  
break; sbv2*fno5  
OFe-e(c1  
p{|!LcSU$2  
//count++; W_.WMbT  
//if(count>4) %9vl  
// siteStop(); DwmK?5p  
} sg`   
hZ_@U?^  
VO JA}$  
System.err.println("文件下载结束!"); cY mgJBG  
} #{_iNra9  
catch(Exception e){e.printStackTrace ();} (vP<}  
} 2$r8^}Nj?  
}TQa<;Q  
|P0!dt7sQ  
//获得文件长度 n f.H0i;  
public long getFileSize() ,>+B>lbJ*  
{ BTc }Kfae  
int nFileLength = -1; 9*Q6/?v  
try{ 9$k0  
URL url = new URL(siteInfoBean.getSSiteURL()); )_n=it$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &cGa~#-u  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?}RPn f  
+>3jMs~&  
t =V| '  
int responseCode=httpConnection.getResponseCode(); 3c%_RI.  
if(responseCode>=400) unKPqc%q=n  
{ e&nE  
processErrorCode(responseCode); f+!k:}K  
return -2; //-2 represent access is error )Fgu'  
} &&% oazR=  
k,eo+qH.Hz  
}ChScY  
String sHeader; ~+ kfb^<-  
3iM7c.f*/  
j)ME%17  
for(int i=1;;i++) JR_%v=n~x  
{ !mZDukfjQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UpaF>,kM  
//Utility.log(in.readLine()); QUeuN?3X\  
sHeader=httpConnection.getHeaderFieldKey(i); .af+h<RG4$  
if(sHeader!=null) ZyM7)!+kPa  
{ r=-b@U.fk>  
if(sHeader.equals("Content-Length")) Ptm=c6H('  
{ iD*21c<kd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .(RZ&*4  
break; xv"v='  
} dBw7l}  
} |yl,7m/B-G  
else a[Nm< qV05  
break; nz|6CP  
} 3n,jrX75u  
} FI,K 0sO/|  
catch(IOException e){e.printStackTrace ();} jB<B_"  
catch(Exception e){e.printStackTrace ();} oN2#Jh%dH  
xkCM*5:  
/!?b&N/d)  
Utility.log(nFileLength); EHy15RL  
D V\7KKJE  
qjObu\r  
return nFileLength; ~R&rQJJeJ  
} qj9[mBkP"  
U&i#cF   
{]bmecz  
//保存下载信息(文件指针位置) Y'{}L@"t  
private void write_nPos() tD*k   
{  !2kM  
try{ %QG3~b% h  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uK] -m  
output.writeInt(nStartPos.length); k%3)J"|/  
for(int i=0;i<nStartPos.length;i++) IL go:xQ  
{ <6Y|vEo!N  
// output.writeLong(nPos); _\=x A6!  
output.writeLong(fileSplitterFetch.nStartPos); )DmydyQ'  
output.writeLong(fileSplitterFetch.nEndPos); CBO*2?]s  
} B}S+/V` Y5  
output.close(); o}DR p4;Ka  
} _dELVs7OL  
catch(IOException e){e.printStackTrace ();} qfG:v Tm  
catch(Exception e){e.printStackTrace ();} Nw9@E R  
} E[WU  
#.rkvoB0N  
R?zlZS.~  
//读取保存的下载信息(文件指针位置) idB1%?<  
private void read_nPos() eL>wKu:r  
{ -:95ypi  
try{ j!@T@ 8J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~/X8Hy!-  
int nCount = input.readInt(); Fv7]1EO.  
nStartPos = new long[nCount]; t{g@z3  
nEndPos = new long[nCount]; ^KdT,^6T  
for(int i=0;i<nStartPos.length;i++) &\I<j\F2/  
{ R%4Yg(-Q  
nStartPos = input.readLong(); [(2^oTSRaq  
nEndPos = input.readLong(); fP:]s@$  
} dG7d}0Ou'  
input.close(); 2 431v@  
} qdLzB  
catch(IOException e){e.printStackTrace ();} RP$h;0EQG  
catch(Exception e){e.printStackTrace ();} %%|pJ%}Q>  
} >yr;Y4y7K  
4qQE9f xdY  
"b402"&  
private void processErrorCode(int nErrorCode) /Yb8= eM  
{ tmOy"mq67  
System.err.println("Error Code : " + nErrorCode); *xJ]e.  
} `v@Z|rv,  
gyq6LRb  
CuK>1_Dq  
//停止文件下载 Fm=jgt3wv8  
public void siteStop() cHt4L]n8n  
{ kQe<a1 8  
bStop = true; ]h~F%   
for(int i=0;i<nStartPos.length;i++) i9Beap/t$  
fileSplitterFetch.splitterStop(); 0J^Z)U>j  
H#7=s{u  
*Lxt{z`9  
} '%4fQ%ID}  
} W**[:n+  
//负责部分文件的抓取 *+zFsu4l  
**FileSplitterFetch.java =dH=3iCG  
*/ SHs [te[  
package NetFox; V,=5}qozQ  
XlD=<$Nk7  
iZ>P>x\  
import java.io.*; p6NPWaBR  
import java.net.*; _h4]gZ  
!?_CIt$p  
akk*f+TD`  
public class FileSplitterFetch extends Thread { FAL#p$y}  
 ZB |s/  
B8eZ}9X  
String sURL; //File URL qE3Ud:j  
long nStartPos; //File Snippet Start Position C[<{>fl)  
long nEndPos; //File Snippet End Position 'zav%}b]L  
int nThreadID; //Thread's ID +'SL5d*  
boolean bDownOver = false; //Downing is over Y- Q)sv  
boolean bStop = false; //Stop identical [u;(4sa}  
FileAccessI fileAccessI = null; //File Access interface H>D sAHS  
Y@:l!4DI  
_f8H%Kgk;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MM]0}65KG  
{ t\LE\[XM>  
this.sURL = sURL; 50dN~(;p  
this.nStartPos = nStart; )b (+=  
this.nEndPos = nEnd; 5L<A7^j  
nThreadID = id; Xp| 4WM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8\9W:D@"x  
} b:'8_jL  
u$[&'D6  
lAA&#-#YG  
public void run() bDIhI}P  
{ yUf`L=C:  
while(nStartPos < nEndPos && !bStop) b$0;fEvIJn  
{ ?]bx]Y;  
ZbVn"he  
% >a /m.$  
try{ y`8U0TE3R  
URL url = new URL(sURL); Ym"^Ds}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]hy@5Jyh  
httpConnection.setRequestProperty("User-Agent","NetFox"); Du +_dr^4  
String sProperty = "bytes="+nStartPos+"-"; QHja4/  
httpConnection.setRequestProperty("RANGE",sProperty); WF*j^ %5  
Utility.log(sProperty); xjF>AAM_Px  
~:k r;n2  
)7!,_r  
InputStream input = httpConnection.getInputStream(); TghT{h@  
//logResponseHead(httpConnection); <$hv{a  
4YI6&  
E+EcXf  
byte[] b = new byte[1024]; Ek_&E7  
int nRead; )MSCyPp5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k&:q|[N  
{ @aN~97 H\  
nStartPos += fileAccessI.write(b,0,nRead); k"%JyO8Y  
//if(nThreadID == 1) %).I &)i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AX&Emz-  
} GIkeZV{4}  
<,it<$f#  
>Ik%_:CC`  
Utility.log("Thread " + nThreadID + " is over!"); _-H,S)kI`  
bDownOver = true; ?Fl O,|   
//nPos = fileAccessI.write (b,0,nRead); 7p\&D?  
} U[Sh){4j  
catch(Exception e){e.printStackTrace ();} <+r~?X_  
} p5OoDo  
} `Ix`/k}  
!5h-$;  
'AWWdz  
//打印回应的头信息 i;/;zG^=_  
public void logResponseHead(HttpURLConnection con) }eA ) m  
{ =O"l/\c^  
for(int i=1;;i++) Drf Au  
{ #@w/S:KbJt  
String header=con.getHeaderFieldKey(i); pYm#iz  
if(header!=null) 7O%^4D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ooB9i No^  
Utility.log(header+" : "+con.getHeaderField(header)); =`>ei  
else 6:8Nz   
break; >'=9sCi  
} >EA\KrjW  
} tUZfQ  
G9xO>Xp^Al  
ZwY mR=  
public void splitterStop() yK9EHJ$  
{ E_$nsM8?  
bStop = true; ,Xn %0]  
} p ^TCr<=  
^~TE$i<   
ar 7.O;e  
} _qk&W_u  
\(=xc2  
G\5Bdo1g  
/* of7p~{3H  
**FileAccess.java 6&6dd_K(  
*//文件访问(定位,写) {|OXiRm'  
package NetFox; S76MY&Vx23  
import java.io.*; -qvMMit%7  
g,o46`6"  
% jf|efxo  
public class FileAccessI implements Serializable{ 7rbw_m`12-  
'byTM?Sp{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (RrC<5"  
RandomAccessFile oSavedFile; -OmpUv-O"  
long nPos; !B#lZjW#  
;.xKVH/@  
{*g{9`   
public FileAccessI() throws IOException F4"bMN  
{ d:vc)]M>f{  
this("",0); xL<c/B`-:  
} ^?\|2H  
9An \uH)mL  
?li/mc.XG  
public FileAccessI(String sName,long nPos) throws IOException Sfc,F8$&N  
{ H/Ql  
oSavedFile = new RandomAccessFile(sName,"rw");  Y%y  
this.nPos = nPos; B<Cg_C  
oSavedFile.seek(nPos); 2'OY,Ooe  
} @qW$un:  
7I]?:%8 h  
x./"SQ=R+  
public synchronized int write(byte[] b,int nStart,int nLen) l O*  
{ /B 3\e3  
int n = -1; l_9ZzN  
try{ &Qj1uf92.  
oSavedFile.write(b,nStart,nLen); 9C Ki$L  
n = nLen; ~@QAa (P.  
} "|Yy "iB[  
catch(IOException e) sredL#]BA  
{ |/8!P Km  
e.printStackTrace (); MT)q?NcG  
} ^ r(]S%  
8KkN "4'  
PA*k |  
return n; ?UIW&*h}  
} Z 5P4 H  
=TzJgx  
{(asy}a9K  
} #j+cl'  
.!lLj1?p  
,!,M'<?"  
/* =oiz@Q@H  
**SiteInfoBean.java o$U{.#  
*/ qe e_wx  
package NetFox; cH:&S=>h  
i PG:w+G  
'L9hM.+  
public class SiteInfoBean { +eKLwM  
#4"eQ*.*"  
Sd.Km a  
private String sSiteURL; //Site's URL (~5]1S}F  
private String sFilePath; //Saved File's Path /F|VYl^_  
private String sFileName; //Saved File's Name Slv:CM M  
private int nSplitter; //Count of Splited Downloading File `)KGajB  
MF*4E9Ue.  
L\bc R  
public SiteInfoBean() kSCpr0c  
{//nSplitter的缺省值为5 &%)F5PT  
//default value of nSplitter is 5 XN?my@_HpM  
this("","","",5); :P%?!'M  
} mMWhUr  
rFm?Bu  
c(b`eUOO  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Bf+~&I#E  
{ 6CGk*s  
sSiteURL= sURL; 3fZoF`<a  
sFilePath = sPath; S5Pn6'w  
sFileName = sName; y@2"[fo3~  
this.nSplitter = nSpiltter; %1{O  
~ oq.yn/1  
hB aG*J{  
} {-]K!tWda  
;p <BiC$b  
iyUnxqP  
public String getSSiteURL() ,+C?UW  
{ (G$Q\>  
return sSiteURL; =,qY\@fq  
} iYw1{U  
O*]}0*CT  
q;f L@L@-  
public void setSSiteURL(String value) 'gD./|Z0  
{ /|h+,]< >  
sSiteURL = value; YD9vWk \/  
} u$ci{<  
=JP Y{'VO  
on5\rY<I:@  
public String getSFilePath() 1~2+w]-kU  
{ P%vouC0W  
return sFilePath; Q?([#  
} R*k;4*1u  
a0B%x!y^  
"fSaM&@[B  
public void setSFilePath(String value) U;u4ey  
{ (6[/7e)  
sFilePath = value; OS>%pgv  
} #hu`X6s"  
83#<Yxk~  
| "M1+(k7  
public String getSFileName() Ytqx 0  
{ Hl{ul'o  
return sFileName; g_>E5z.  
} n? =O@yq  
cf"!U+x  
,Tx38  
public void setSFileName(String value) ~-%z:Re'_  
{ ZdPqU \G^q  
sFileName = value; _ogN   
} %X%f0J  
\FCPD.2s+  
i/!KUbt  
public int getNSplitter() WHLTJ]OB  
{ d#ab"&$bv  
return nSplitter; "Z&_*F.[O  
} P+_1*lOG  
"^ dMCS@  
^AZv4H*~  
public void setNSplitter(int nCount) P-yVc2YH  
{ C+t|fSJ  
nSplitter = nCount; d}Y#l}!E6  
} sE{5&aCSR  
} n3eWqwQ$5  
E\9HZ;}G  
5UK}AkEe&x  
/* N693eN!  
**Utility.java +~ Y.m8  
*/ 5s4x%L (~}  
package NetFox; .;,,{ ;  
v9f%IE4fX  
XGYsTquSe  
public class Utility { !g|[A7<|  
h{jm  
o{hZjn-  
public Utility()  3(*vZ  
{ i_`Po%   
z t!>  
Zba<|C  
} LCHw.  
Pe11a zJ  
//线程睡眠 ]]_c3LJ2`  
public static void sleep(int nSecond) dww4o~hO  
{ FS!vnl8`  
try{ or7l} X  
Thread.sleep(nSecond); *8u<?~9F  
} a%an={  
catch(Exception e) 5~#oQ&  
{ w-@6qMJ  
e.printStackTrace (); ye}86{l  
} Aaz:C5dtU  
} G#E8xA"{/  
IkGM~3e  
//日志 0/%RrE  
public static void log(String sMsg) U` )d `4"  
{ tpgD{BY^wJ  
System.err.println(sMsg); b`;&o^7gMO  
} g]?>6 %#rA  
u:wf :^  
<<@F{B7h  
public static void log(int sMsg) /7.//klN  
{ +*e Vi3  
System.err.println(sMsg); <0Gk:NB,  
} -xyY6bxL  
} ybIqn0&[  
iUqD>OV  
jG#e% `'  
/* gS|6,A9  
**TestMethod.java rTST_$"_6  
*/ %hz5)  
package NetFox; Y%(8'Ch  
Q5 o0!w  
YCdtf7P=q  
public class TestMethod { Y|KT3  
Cw5 B p9  
nLrCy5R:  
public TestMethod() @j(2tJ,w  
{ ///xx/weblogic60b2_win.exe srKEtd"  
try{ a:1$idj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {aU|BdATI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {817Svp@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A9GSeW<  
fileFetch.start(); :j32 :/u  
} QUz4 Kt  
catch(Exception e){e.printStackTrace ();} .rlLt5b%  
a`U/|[JM  
_@_EQ!=  
} X LY>}r  
4i"fHVp8  
IfP?+yPa  
public static void main(String[] args) G//hZwf0  
{ lxR]Bh+  
new TestMethod(); @)ls+}=Y  
} _]0<G8|Rv  
} YlZ&4   
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