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http断点续传简单实现(java)

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/* ~VO?PfxZ  
**SiteFileFetch.java G2_l}q~  
*/ x;>~;vmi  
package NetFox; ^sZ,(sc{G  
import java.io.*; ]`n6H[6O  
import java.net.*; 7{DSLKtN  
}?z_sNrDk  
{ BDUl3T  
public class SiteFileFetch extends Thread { vWpkU<&3|  
8G p%Q  
iN@+,]Yjl  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0RGSv!w  
long[] nStartPos; //开始位置 J@ pCF@'  
long[] nEndPos; //结束位置 # Q_ d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E6y ?DXW H  
long nFileLength; //文件长度 D|R,$ v:  
boolean bFirst = true; //是否第一次取文件 o;Ma)/P  
boolean bStop = false; //停止标志 n42XqR  
File tmpFile; //文件下载的临时信息 l?LP:;S  
DataOutputStream output; //输出到文件的输出流 6(.]TEu0  
3a]Omuu|=  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) f^[:w1X$sM  
public SiteFileFetch(SiteInfoBean bean) throws IOException Hb{G RG70  
{ hA_Y@&=W  
siteInfoBean = bean; X` FFI6pb  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~Uw<E:?v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1k! xG$g0  
if(tmpFile.exists ()) 6H_7M(f  
{ 5PU$D`7it  
bFirst = false; x_TtS|   
read_nPos(); {Deg1V!x>  
} Ss~dK-{e7  
else !@[@xdV  
{ .TTXg,8#D  
nStartPos = new long[bean.getNSplitter()]; d;10[8:5=  
nEndPos = new long[bean.getNSplitter()]; 27!9LU  
} O*7Gl G  
[J.-gN$X@  
? 3 l4U  
5+[`x ']l  
} GGR hM1II  
tu6Q7CjW8  
'YcoF;&[C  
public void run() +u:Q+PkM  
{ {|~22UkF[V  
//获得文件长度 ^"!j m  
//分割文件 ^SouA[  
//实例FileSplitterFetch ?!J{Mrdn  
//启动FileSplitterFetch线程 ;w_f^R #  
//等待子线程返回 1$g]&'  
try{ aI6fPQe  
if(bFirst) ,^UNQO*{GI  
{ s2-p -n  
nFileLength = getFileSize(); 'v"{frh   
if(nFileLength == -1) >dW~o_u'QN  
{ J c~{ E  
System.err.println("File Length is not known!"); }I\hO L  
} 0{P Rv./`  
else if(nFileLength == -2) *y;(c)_w/%  
{ ^sNj[%I R  
System.err.println("File is not access!"); 8W|qm;J98  
} d|9B3I*I  
else j'V# =vH  
{ , LP |M:  
for(int i=0;i<nStartPos.length;i++) C>vp oCA  
{ + W ? / A]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p-=+i   
} 4$=Dq$4z  
for(int i=0;i<nEndPos.length-1;i++) hYS*J908  
{ 8tM40/U$  
nEndPos = nStartPos[i+1]; 72gQ<Si  
} 0"~`U.k~M  
nEndPos[nEndPos.length-1] = nFileLength; h] (BTb#-  
} tnbtfG;z#  
} :n:Gr?  
KMxP%dV/=  
Sn\S `D  
//启动子线程 HrUQ X4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H h4G3h0  
for(int i=0;i<nStartPos.length;i++) pr2b<(Pm  
{ TS9=A1J#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >4A~?=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5Mfs)a4j.  
nStartPos,nEndPos,i); &VIX?UngE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f((pRP   
fileSplitterFetch.start(); 2l)J,z  
} lD;="b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wL'tGAv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (GVH#}uB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g7*ii X  
nEndPos = " + nFileLength); nwk66o:|  
// fileSplitterFetch[nPos.length-1].start(); P&@:''  
{ jnQoxN  
8#OcrJzC  
//等待子线程结束 1sL#XB$@N  
//int count = 0; cSYW)c|t  
//是否结束while循环 J`T1 88  
boolean breakWhile = false; Y"G U"n~  
}s_'q~R  
aI$D qnF4  
while(!bStop) 9]AiaV9  
{ ffuV158a&  
write_nPos(); x&6SjlDb$K  
Utility.sleep(500); ceakTAB[  
breakWhile = true; N;XaK+_2F  
D"WqJcDt  
y$VYWcFE  
for(int i=0;i<nStartPos.length;i++) 1]HEwTT/1_  
{ $2uZdl8Rvj  
if(!fileSplitterFetch.bDownOver) V6.xp{[  
{ uqy b  
breakWhile = false; 7 tOOruiC  
break; W+[XNIg5   
} ?)$+W+vK  
} ,EyZ2`|  
if(breakWhile) En:.U9?X  
break; =yv_i]9AN  
j?&Rf,,%  
Ys@M1o  
//count++; bi:m;R  
//if(count>4) E5d?toZ,8"  
// siteStop(); bT|N Z!V  
} " gB.  
, Vz 1l_7  
|1GR:b24  
System.err.println("文件下载结束!"); 'J R2@W`]]  
} 2ZMYA=[!  
catch(Exception e){e.printStackTrace ();} p@H]F<  
} wYtL1D(  
6fvzTd},  
l MCoc'ae  
//获得文件长度 c[:OK9TH  
public long getFileSize() yvxdl=s  
{ HC0q_%j  
int nFileLength = -1; 3.q%?S}*  
try{ CmaV>  
URL url = new URL(siteInfoBean.getSSiteURL()); O) ks  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ueO&%  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5Xn+cw*  
V[f-Nj Kf  
Kq}/`P  
int responseCode=httpConnection.getResponseCode(); n:zoN2lC  
if(responseCode>=400) S<"M5e  
{ 1O bxQ_x  
processErrorCode(responseCode); J/3qJst  
return -2; //-2 represent access is error E#t;G: +A  
} ncg5%(2  
p[BF4h{E  
Nx~9Ug  
String sHeader; ^06f\7A  
3F'{JP  
a!MhxM5  
for(int i=1;;i++) KlMrM% ;y  
{ #3@ Du(_n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k9j_#\E[  
//Utility.log(in.readLine()); iOpMU  
sHeader=httpConnection.getHeaderFieldKey(i); _@CY_`a  
if(sHeader!=null) {9sA'5  
{ c$),/0td|  
if(sHeader.equals("Content-Length")) ea3;1-b:  
{ %,$Ms?,n`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h^klP:Q  
break; l2uh"!  
} qd*3| O^  
} -x~h.s,  
else O$jj&  
break; * z|i{=W F  
} E~?0Yrm F  
} ~[|&)}q  
catch(IOException e){e.printStackTrace ();} NNZ%jJy?=,  
catch(Exception e){e.printStackTrace ();} s BP.P7u  
y6.}h9~  
j .Ro(0%  
Utility.log(nFileLength); Le3H!9lbc  
SH>L3@Za  
}ge~Nu>w  
return nFileLength; 9{{QdN8  
} hn9'M!*:O  
G t 4| ]  
;V(- ;O  
//保存下载信息(文件指针位置) )%rGD =2~  
private void write_nPos() XMb]&VvH  
{ bJc<FL<E  
try{ K_/8MLJQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >|%dN jf@Q  
output.writeInt(nStartPos.length); g_lj/u]P  
for(int i=0;i<nStartPos.length;i++) P7GuFn/p~2  
{ _2Sb?]Xn  
// output.writeLong(nPos); YXE?b@W"  
output.writeLong(fileSplitterFetch.nStartPos); j^ L"l;m  
output.writeLong(fileSplitterFetch.nEndPos); #m_3l s}W$  
} ~!( (?8"  
output.close(); C/Vs+aW n  
} om%L>zfB  
catch(IOException e){e.printStackTrace ();} KL:x!GsV5e  
catch(Exception e){e.printStackTrace ();} r[xj,eIb  
} 4yhan/zA  
^):m^w.  
<CrNDY  
//读取保存的下载信息(文件指针位置) 9kmEg$WM  
private void read_nPos() uC{qaMQ  
{ *_G(*yAe(  
try{ {)j~5m.,/o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e~ #;ux  
int nCount = input.readInt(); I&9_F% rX  
nStartPos = new long[nCount]; N{L'Q0!  
nEndPos = new long[nCount]; rQ~7BlE  
for(int i=0;i<nStartPos.length;i++) @tQu3Rq@  
{ l,cnM r^.W  
nStartPos = input.readLong();  lJaR,,  
nEndPos = input.readLong(); zTtn`j$  
} npsDy&  
input.close(); ~JjL411pG  
} 5,/rh,?  
catch(IOException e){e.printStackTrace ();} A-5xgp,  
catch(Exception e){e.printStackTrace ();} x*}41;j}C  
} yW::`  
^)$(Fe<  
;Du+C%  
private void processErrorCode(int nErrorCode) p,_,o3@~  
{ Y+il>.Z  
System.err.println("Error Code : " + nErrorCode); "B18|#v  
} Z(Styn/x  
~s.~X5  
)xJCH9h  
//停止文件下载 ?:@13wm  
public void siteStop()  "R8:s  
{ ZAe'lgS  
bStop = true; 5^kLNNum  
for(int i=0;i<nStartPos.length;i++) b1rW0}A  
fileSplitterFetch.splitterStop(); a%\6L  
<sU?q<MC  
Q-A:0F&{t  
} m |K"I3W$  
} GYv D*?uBc  
//负责部分文件的抓取 _+c' z  
**FileSplitterFetch.java MW^(  
*/ zKRt\;PW  
package NetFox; Fjnp0:p9X  
t:MeSO  
%:yp>nm  
import java.io.*; &j}08aK%  
import java.net.*; <x&0a$I  
12{F  
a1^CpeG~  
public class FileSplitterFetch extends Thread { d|I_SI1  
"LwLTPC2  
n6AN  
String sURL; //File URL KGM9 b  
long nStartPos; //File Snippet Start Position |3LD"!rEx  
long nEndPos; //File Snippet End Position &,v- AL$:Q  
int nThreadID; //Thread's ID W=E+/ZvPt  
boolean bDownOver = false; //Downing is over X`/GiYTu  
boolean bStop = false; //Stop identical pm2-F]  
FileAccessI fileAccessI = null; //File Access interface %@L[=\ 9  
[j3-a4W u  
{oXU)9vj  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException fyt ODsb>  
{ C8{bqmlm@  
this.sURL = sURL; $7bLw)7  
this.nStartPos = nStart; % w\   
this.nEndPos = nEnd; WdWMZh  
nThreadID = id; q?R^~r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x3>ZO.Q  
} &7\=J w7w  
.j et0w  
!+UU[uM  
public void run() ^`~s#L7  
{ /"+CH\) E  
while(nStartPos < nEndPos && !bStop) ='W=  
{ 64LX[8Ax#  
\T'.b93~B  
-1_WE/Ps  
try{ 1'NJ[ C`  
URL url = new URL(sURL); %`EyG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *&vlfH  
httpConnection.setRequestProperty("User-Agent","NetFox"); f:9b q}vH  
String sProperty = "bytes="+nStartPos+"-"; I`~Giz7@  
httpConnection.setRequestProperty("RANGE",sProperty); c>|1%}"?  
Utility.log(sProperty); @$Xl*WT7  
12i<b  
L[s`8u<_)z  
InputStream input = httpConnection.getInputStream(); adcH3rV  
//logResponseHead(httpConnection); @~z4GTF9i  
{xD\w^  
4 -CGe  
byte[] b = new byte[1024]; bJ"}-s+Dx  
int nRead; _4f=\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G$^u2wz.  
{ b F MBIA|  
nStartPos += fileAccessI.write(b,0,nRead); Z<jC,r  
//if(nThreadID == 1) *V`E)maU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B,q)<z6<  
} s||c#+j"8  
u?F^gIw  
j].=,M<dxE  
Utility.log("Thread " + nThreadID + " is over!"); %ws@t"aER  
bDownOver = true; mP] a}[  
//nPos = fileAccessI.write (b,0,nRead); ,/ YTW@N  
} qOTo p-  
catch(Exception e){e.printStackTrace ();} {/|tVc63  
} zNO,vR[\  
} xrZzfg  
/u&7!>,  
o(gV;>I  
//打印回应的头信息 [ KDNKK  
public void logResponseHead(HttpURLConnection con) O@>ZYA%  
{ >g;995tG  
for(int i=1;;i++) v@d]*TG  
{ ]&?8l:3-G  
String header=con.getHeaderFieldKey(i); K8JshF Ie  
if(header!=null) arc{:u.K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); uC! dy  
Utility.log(header+" : "+con.getHeaderField(header)); Y<t(m$s  
else `)tIXMn  
break; O9*l6^Scw  
} >rYkVlv  
} 6VtN4c .Q  
)&$mFwf  
)!lx'>0>  
public void splitterStop() 'si{6t|  
{ 2BO&OX|X  
bStop = true; iOtf7.@  
} Os/?iGlD*E  
d/[kky}  
} 4ZWAzH  
} tZY6{,K%4  
< w;49 0g  
25;(`Td 5  
/* ]2c0?f*Y7  
**FileAccess.java L1kA AR  
*//文件访问(定位,写) b"nD5r  
package NetFox; +*IRI/KUD  
import java.io.*; K@vU_x0Sl  
/bF>cpM  
c=D~hzN  
public class FileAccessI implements Serializable{ yUN>mD-  
(K('@W%\?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q<K/q"0-l  
RandomAccessFile oSavedFile; ovZ!}  
long nPos; xKkXr-yb`f  
}S;A%gYm  
Svdmg D!  
public FileAccessI() throws IOException 30O7u3Zrb  
{ y@<&A~Cl^  
this("",0); #itZ~tol  
} V@nZ_.  
('2Z&5  
,'n`]@0?\  
public FileAccessI(String sName,long nPos) throws IOException |-HNHUF  
{ KV! (   
oSavedFile = new RandomAccessFile(sName,"rw"); WtC&Qyuq  
this.nPos = nPos; z0UtKE^b  
oSavedFile.seek(nPos); *;F:6p4_  
} #8$" 84&N.  
e|q~t {=9S  
J06 D_'{  
public synchronized int write(byte[] b,int nStart,int nLen) >uYU_/y$2  
{ hrGX65>  
int n = -1; !;K zR&  
try{ {&a6<y#-  
oSavedFile.write(b,nStart,nLen); DPkH:X  
n = nLen; xUTTRJ(\  
} {w@9\LsU  
catch(IOException e) D^}2ilk!  
{ P&yB(M-z  
e.printStackTrace (); +.gj/uy*  
} /!N=@z)  
ZZ T 9t#~  
/&9R*xNST#  
return n; ^9><qKbO  
} X]o"vx%C  
!L<z(dV|(  
Gzs$0Ki=  
} r7^v@  
K & %8w  
 n}- _fx  
/* 8A}<-?>  
**SiteInfoBean.java "x nULQK  
*/ 7-0j8$`  
package NetFox; C{+JrHV%h  
P#V}l'j(<a  
QMy1!:Z&!  
public class SiteInfoBean { 5tk7H2K^<  
/,~g"y.;,  
skU }BUK6  
private String sSiteURL; //Site's URL 4dm0:, G  
private String sFilePath; //Saved File's Path 0{I-x^FI  
private String sFileName; //Saved File's Name )1YX+',"  
private int nSplitter; //Count of Splited Downloading File VGc.yM)& j  
itg"dGDk  
jeB"j  
public SiteInfoBean() MTq/  
{//nSplitter的缺省值为5 Yh Ow0 x  
//default value of nSplitter is 5 m77 !i>V)  
this("","","",5); G_zK .N   
} .*X=[" F  
g)!q4 -q  
Vol}wc  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;/kmV~KG  
{ eNO[ikm  
sSiteURL= sURL; !R gj'{  
sFilePath = sPath; -s1.v$ g  
sFileName = sName; i29a1nD4Hm  
this.nSplitter = nSpiltter; 9p1@Lfbj  
>&k`NXS|V  
B79~-,Yh  
} KXpbee  
o,S(;6pDJ  
%$'fq*8b  
public String getSSiteURL() $*LBZcL  
{ sZ7~AJ  
return sSiteURL; j)#yyK{k2s  
} 7j29wvSp5  
z@ `u$D$n  
hm k ~  
public void setSSiteURL(String value) [_}8Vv&6  
{ Rf2mBjJ(z  
sSiteURL = value; /a9CqK  
} C7f*Q[  
%|1s9?h7\  
id" l"  
public String getSFilePath() ?YUL~P  
{ V DZOJM)(  
return sFilePath; ]EUQMyR  
} vp9wRGd  
Pc7p2  
lR9uD9Dr  
public void setSFilePath(String value) n,LM"N:   
{ e Qk5:{[  
sFilePath = value; ?RW1%+[  
} DrbjklcUU  
$o9@ ?2  
WBA7G  
public String getSFileName() ^~6gkS }  
{ iq^;csyKb  
return sFileName; Koj9]2<0  
} p L^3*B.Nr  
`M. I.Z_  
%<'.c9u5  
public void setSFileName(String value) 6eA)d#  
{ I6gduvkXi4  
sFileName = value; YpRhl(|  
} GV28&!4sS  
p )]x,F  
& JJ*?Dl  
public int getNSplitter() _ n1:v~  
{ shP}T[<  
return nSplitter; x9S9%JG :  
} ?;.=o?e9  
@A<~bod  
JfK4|{@  
public void setNSplitter(int nCount) SU6Aq?`@  
{ ^HtB!Xc  
nSplitter = nCount; Pl-9FLJ  
} "WO0 rh`  
} ?STO#<a  
MZB}O" r  
{`T^&b k  
/* ,nGQVb   
**Utility.java TtKKU4yp  
*/ -_eG/o=M  
package NetFox; $<Y%4LI  
OdNcuiLa  
Zm7, O8  
public class Utility { [1ClZ~f  
m{~L Fhhd1  
m~fDDQs  
public Utility()  pn) {v  
{ mEkYT  
w`3.wALb  
N93R(x)%  
} xU6dRjYhH9  
TeO'E<@  
//线程睡眠 K5\l (BB  
public static void sleep(int nSecond) UO!} 0'  
{ e$JCak=  
try{ zr_L V_e  
Thread.sleep(nSecond); &A`,hF8  
}  Y(2Z<d  
catch(Exception e) Jf\`?g3#  
{ (0.JoeA`y  
e.printStackTrace (); R*XZPzg%  
} yF%e)6  
} Q<ia  
bZK^q B  
//日志 pjFj{  
public static void log(String sMsg) @Y>PtA&w*  
{ 0vBQzM Q  
System.err.println(sMsg); H*P+>j&  
} Zk>m!F>,p  
a/3'!}&e  
t~nW&]E  
public static void log(int sMsg) %+;l|Z{Uf  
{ 5,V*aP  
System.err.println(sMsg); "r3h+(5  
} 3bjCa\ "  
} 2V u?Y  
9 `q(_\x  
mFxt +\  
/* H~SU:B:  
**TestMethod.java D ] n|d+  
*/ U>m{B|H  
package NetFox; ]=I2:Rb  
,dw\y/dn  
{;zHkmx  
public class TestMethod { o@]n<ZYo  
_x#y   
bAuiMw7!  
public TestMethod() V[kn'QkWv  
{ ///xx/weblogic60b2_win.exe 0uPcEpIA  
try{ +7n vy^m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aGsO~ODc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s{V&vRr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a|#pl!  
fileFetch.start(); nn$^iw`  
} ,j\uvi(Y  
catch(Exception e){e.printStackTrace ();} v0tFU!Q%  
dLwP7#r  
8*&73cp  
} )  LTV+?  
ko'V8r `V  
8}4.x3uw  
public static void main(String[] args) jVN=_Y}\  
{ ?hR0 MnP  
new TestMethod(); 8m `Y  
} aG4 ^xOD  
} \Cin%S. C  
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