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http断点续传简单实现(java)

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/* Drgv`z  
**SiteFileFetch.java k<nZ+! M  
*/  twHVv  
package NetFox; )5Q~I,dP  
import java.io.*; YlJ@XpKM  
import java.net.*; lV3x*4O=  
e{'BAj  
Fc)@,/R"v  
public class SiteFileFetch extends Thread { 2G & a{  
d=$Mim  
Z!a =dnwHz  
SiteInfoBean siteInfoBean = null; //文件信息Bean PfAgM1   
long[] nStartPos; //开始位置 7FP*oN?  
long[] nEndPos; //结束位置 $D~0~gn~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jE.N ev/  
long nFileLength; //文件长度 W s3)gvpPA  
boolean bFirst = true; //是否第一次取文件 V# }!-Xj  
boolean bStop = false; //停止标志 t9GR69v:?  
File tmpFile; //文件下载的临时信息 z3{G9Np  
DataOutputStream output; //输出到文件的输出流 n:I,PS0H<  
Q",t3i4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Y!aSs3c  
public SiteFileFetch(SiteInfoBean bean) throws IOException >NGj =L<  
{ RtkEGxw*^  
siteInfoBean = bean; WH#1 zv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); > ym,{EHK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rQ{7j!Im  
if(tmpFile.exists ()) A_"w^E{P  
{ niMsQ  
bFirst = false; /e5O"@  
read_nPos(); :[.vM  
} IEL%!RFG  
else 6fE7W>la  
{ [t m_Mg  
nStartPos = new long[bean.getNSplitter()]; b i',j0B  
nEndPos = new long[bean.getNSplitter()]; :;%2BSgFU  
} K C*e/J  
y;m|  
i<C*j4qQ  
UP$.+<vm  
} w8")w*9Lmg  
9d0@wq.  
=g7x' kN  
public void run() nSDMOyj+  
{ zH72'"w  
//获得文件长度 m+`cS=-.  
//分割文件 ]\-A;}\e  
//实例FileSplitterFetch ch*8B(:  
//启动FileSplitterFetch线程 (U D nsF  
//等待子线程返回 T= 80,  
try{ kUb>^- -K  
if(bFirst) 3,_aAgeE  
{ o"s)eh  
nFileLength = getFileSize(); W<h)HhyG  
if(nFileLength == -1) k&M;,e3v6  
{ `z}?"BW|  
System.err.println("File Length is not known!"); yt+L0wzzB  
} (fH#I tf  
else if(nFileLength == -2) ydEoC$?0  
{ xWH.^o,"  
System.err.println("File is not access!"); >>4qJ%bL  
} sU<Wnz\[  
else }`@vF|2L  
{ h6Ub}(Ov  
for(int i=0;i<nStartPos.length;i++) :^lI`9'*R  
{ LRxZcxmy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); MVpGWTH@F  
} ~p6 V,Q  
for(int i=0;i<nEndPos.length-1;i++) u4cnE"  
{ &C5_g$Ma.Z  
nEndPos = nStartPos[i+1]; IV~>I-rd  
} +zqn<<9  
nEndPos[nEndPos.length-1] = nFileLength; 7uqzm  
} B&M%I:i  
} SBu"3ym  
$j%'{)gK  
Y sC>i`n9  
//启动子线程 ,C\i^>=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (!u~CZ;  
for(int i=0;i<nStartPos.length;i++) ^cC,.Fdw  
{ ^ 'MT0j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 93>jr<A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *g"Nq+i@  
nStartPos,nEndPos,i); 1/B>XkCJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /s&9SYF  
fileSplitterFetch.start(); tn\yI!a  
} ZoW?nxY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G`D`Af/B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vQG5*pR*w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @Rze| T.  
nEndPos = " + nFileLength); ;J( 8 L  
// fileSplitterFetch[nPos.length-1].start(); 6xmZXp d!  
3lL-)<0A(  
F}yW/  
//等待子线程结束 ](]i 'fE>  
//int count = 0; [-1^-bb  
//是否结束while循环 BGZ#wru  
boolean breakWhile = false; *->W^1eGM  
dA}-]  
x M/+L:_<  
while(!bStop) Ys9[5@7  
{ _IHV7*u{;  
write_nPos(); .^33MWu6  
Utility.sleep(500); aH(J,XY  
breakWhile = true; wYXQlxdy  
:wyno#8`-  
Vi$~-6n&  
for(int i=0;i<nStartPos.length;i++) i$"F{|Z0  
{ BN5[,J  
if(!fileSplitterFetch.bDownOver) %bn jgy  
{ h|9L5  
breakWhile = false;  M mj;-u  
break; |*eZD-f  
} S"QWB`W2  
} !RS}NS  
if(breakWhile) 5X$jl;6  
break; VR8-&N  
V*;(kEqj  
GT.,  
//count++; ;6 D@A  
//if(count>4) ea2ayT  
// siteStop(); 9Q^r O26+  
} K=Z|/Kkh  
=!A_^;NQf  
%g$o/A$  
System.err.println("文件下载结束!"); ^$jb7HMObI  
} {%5eMyF#  
catch(Exception e){e.printStackTrace ();} ?3`UbN:  
} :K,i\  
(UD@q>c  
k/_ 59@)  
//获得文件长度 dh iuI|?@  
public long getFileSize() E?f-wQF  
{ l}|%5.5-  
int nFileLength = -1; DH!~ BB;  
try{ OX7M8cmc+  
URL url = new URL(siteInfoBean.getSSiteURL()); Yx%Hs5}8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a$OE0zn`  
httpConnection.setRequestProperty("User-Agent","NetFox"); X=&ET)8-Y  
[=q1T3  
9d659i C  
int responseCode=httpConnection.getResponseCode(); ^98~U\ar  
if(responseCode>=400) Tn e4  
{ qOtgve`jX  
processErrorCode(responseCode); kd(8I_i@  
return -2; //-2 represent access is error `wEb<H  
} 20h, ^  
zT]8KA   
Af2( 5]  
String sHeader; e{K 215  
-zgI_u9=EB  
hBUn \~z  
for(int i=1;;i++) nPl?K:(  
{ 8C:z"@o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w+|L+h3L7  
//Utility.log(in.readLine()); $szqy?i 0?  
sHeader=httpConnection.getHeaderFieldKey(i); 5r|,CQ7o  
if(sHeader!=null) OX!tsARC@  
{ 19)i*\+  
if(sHeader.equals("Content-Length")) I;|B.j  
{ sY Qk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _S1>j7RQo  
break; lT?v^\(H  
} x~~|.C ,  
} 8qTys8  
else dn+KH+v  
break; s};{ZAtE  
} ASySiHz  
} *Kg ks4  
catch(IOException e){e.printStackTrace ();} "?xHlYj@+  
catch(Exception e){e.printStackTrace ();} D=Gtq6jd  
zu{P#~21  
,!y$qVg'\f  
Utility.log(nFileLength); PiIpnoM  
b=NxUd O  
xs bE TP?  
return nFileLength; WPMSm<[  
} )9`qG:b'  
KL57# gV  
,T$U'&;  
//保存下载信息(文件指针位置) +gtbcF@rx  
private void write_nPos() O KR "4n:  
{ ,/F~ Y&1I  
try{ WiR(;m<g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]Ie 0S~  
output.writeInt(nStartPos.length); *zvx$yJ?  
for(int i=0;i<nStartPos.length;i++) (exa<hh  
{ b9HtR-iR;  
// output.writeLong(nPos); 6j]0R*B7`Q  
output.writeLong(fileSplitterFetch.nStartPos); m8hk:4Ae  
output.writeLong(fileSplitterFetch.nEndPos); />pI8 g<  
} 6Y?|w3f   
output.close(); Fj3a.'  
} /]Md~=yNp  
catch(IOException e){e.printStackTrace ();} h2]P]@nW;W  
catch(Exception e){e.printStackTrace ();} xj;H&swo  
} ~IBP|)WA-  
qiBVG H  
:>f )g  
//读取保存的下载信息(文件指针位置) @,7GaK\  
private void read_nPos() k)=s>&hl  
{ jcf7n`L  
try{ joAv{Tc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C1n>M}b  
int nCount = input.readInt(); qWPkT$ u  
nStartPos = new long[nCount]; A[{yCn`tM  
nEndPos = new long[nCount]; CxW>~O:  
for(int i=0;i<nStartPos.length;i++) FHg 9OI67  
{ 8^1 Te m  
nStartPos = input.readLong(); D.u{~  
nEndPos = input.readLong(); mL{6L?  
} "&?kC2Y|  
input.close(); ^A&1^B  
} `e&Suyf4B  
catch(IOException e){e.printStackTrace ();} G}raA%  
catch(Exception e){e.printStackTrace ();} Z0", !6nS  
} L^?qOylu  
+lcbi  
4p;`C  
private void processErrorCode(int nErrorCode) -- 95Jz  
{ qt"m  
System.err.println("Error Code : " + nErrorCode); .|fH y  
} \V~eVf;~  
Moza".fiN  
j>"@,B g*  
//停止文件下载 J<h $ wM  
public void siteStop() `l[c_%Bm  
{ .?sx&2R2  
bStop = true; SZ'R59Ee<  
for(int i=0;i<nStartPos.length;i++) flbd0NB  
fileSplitterFetch.splitterStop(); ;$wVu|&  
Wt-GjxGi  
bJTBjS-7  
} iz PDd{[  
} z$. 88 ^  
//负责部分文件的抓取 Y\8)OBZ  
**FileSplitterFetch.java O m2d .7S  
*/ ?NsW|w_  
package NetFox; WP'!*[z  
kxhWq:[c  
;dgp+  
import java.io.*; 7[XRd9a5(  
import java.net.*; +\ .Lp 5  
>KhOz[Zg  
:':s@gqr  
public class FileSplitterFetch extends Thread { 9qzHS~l  
WW~sNC\3`(  
p}~JgEE  
String sURL; //File URL ;[OH(!  
long nStartPos; //File Snippet Start Position i<Zc"v;  
long nEndPos; //File Snippet End Position VjZ|$k  
int nThreadID; //Thread's ID 4!no~ $b  
boolean bDownOver = false; //Downing is over Q/0Tj]D  
boolean bStop = false; //Stop identical 7;wd(8  
FileAccessI fileAccessI = null; //File Access interface `|& O*`  
@lrztM  
A$0fKko  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Pu$Tk |  
{ ;85>xHK  
this.sURL = sURL; FWgpnI\X|{  
this.nStartPos = nStart; ]Q)OL  
this.nEndPos = nEnd; #.)0xfGW)n  
nThreadID = id; uz jU2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @`- 4G2IU}  
} JP [K;/  
y}ev ,j  
c4eBt))}V  
public void run() j'"J%e]  
{ JU&c.p /  
while(nStartPos < nEndPos && !bStop) <6 Uf.u`  
{ \"OG6G_>$  
Btn]}8K  
; )@~  
try{ _F|Ek;y%  
URL url = new URL(sURL); }N6.Uu 5zI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ` 7V]y -  
httpConnection.setRequestProperty("User-Agent","NetFox"); 56kI 5:  
String sProperty = "bytes="+nStartPos+"-"; kJT)r6  
httpConnection.setRequestProperty("RANGE",sProperty); ;"-&1qHN  
Utility.log(sProperty); ,(^*+G.i  
ope^~+c~\  
sWnLEw  
InputStream input = httpConnection.getInputStream(); z5*'{t)  
//logResponseHead(httpConnection); l}A93jSL  
M&9+6e'-F  
60?%<oJ oH  
byte[] b = new byte[1024]; tW}'g:s  
int nRead; \xw5JGm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q(W3i^778  
{ FP4P|kl/9'  
nStartPos += fileAccessI.write(b,0,nRead); 5D//*}b,  
//if(nThreadID == 1) &Hs!:43E-<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3 {sVVq5Y  
} T'Dv.h  
[2 M'PT3  
T%*D~=fQ'  
Utility.log("Thread " + nThreadID + " is over!"); ]2qo+yB  
bDownOver = true; uiR8,H9*M  
//nPos = fileAccessI.write (b,0,nRead); DT&@^$?  
} 07{)?1cod4  
catch(Exception e){e.printStackTrace ();} t&e{_|i#+  
} }a(dyr`S  
} 0*{%=M  
m G YoM  
k!'a,R:  
//打印回应的头信息 ,/|T-Ka  
public void logResponseHead(HttpURLConnection con) m#\ dSl}  
{ {V CWn95Z  
for(int i=1;;i++) )irEM  
{ 'YSHi\z ](  
String header=con.getHeaderFieldKey(i); z9Rp`z&`E  
if(header!=null) 3eQ&F~S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `*1p0~cu  
Utility.log(header+" : "+con.getHeaderField(header)); p>8D;#Hm L  
else 0{-q#/  
break; NyNXP_8  
} ' %o#q6O  
} WX3-\Y5E  
"87:?v[[1  
=fFP5e ['  
public void splitterStop() sdw(R#GE  
{ =]0&i]z[.  
bStop = true; v0.#Sl-  
} > /caXvS  
)bscBj@  
T{[=oH+  
} X$W~mQma6  
<frutU16\  
; kI134i=  
/* ge8ZsaiU  
**FileAccess.java 3L}A3de'  
*//文件访问(定位,写)  H6/$d  
package NetFox; \z(gqkc 6  
import java.io.*; q^<?]8  
II{&{S'HU  
p H2Sbs:Tk  
public class FileAccessI implements Serializable{ v):Or'$~M  
ji0@P'^;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t\7[f >  
RandomAccessFile oSavedFile; z!9-:  
long nPos; E+;7>ja  
</*6wpN  
>tW#/\x{  
public FileAccessI() throws IOException sLxc(d'A  
{ o|["SYIf  
this("",0); A^<jy=F&  
} |aq"#Ml)  
JDT`C2-Q  
P@c5pc#|  
public FileAccessI(String sName,long nPos) throws IOException aAUvlb  
{ r\^b(rNe  
oSavedFile = new RandomAccessFile(sName,"rw"); m!HJj>GEo  
this.nPos = nPos; RPRBmb940  
oSavedFile.seek(nPos); Z/+#pWBI!  
} 6(ol1 (U  
$1`2 kM5  
cSV aI  
public synchronized int write(byte[] b,int nStart,int nLen) DN:EB @  
{ \ }G> 8^  
int n = -1; k;FUs[  
try{ 3)ywX&4"L  
oSavedFile.write(b,nStart,nLen); ^k9I(f^c-_  
n = nLen; {3aua:q  
} -ZLJeY L  
catch(IOException e) #KZBsa@p  
{ ;NITc  
e.printStackTrace (); f%}xO+.s  
} s?nR 4  
(<C3Vts))  
U # qK.  
return n; 9djk[ttA)  
} }*]-jWt1J\  
1iF1GkLEq  
pYf-S?Y/V  
} =D"#U#>;7&  
{R `[kt  
NTs aW}g  
/* Z(CkZll  
**SiteInfoBean.java "=MeM)K  
*/ e$rZ5X  
package NetFox; b d!Y\OD  
t"oeQ*d%  
I-l_TpM)  
public class SiteInfoBean { &{t,'[ u  
M9%$lCl   
5:_}zu|!u  
private String sSiteURL; //Site's URL j1T#yt J  
private String sFilePath; //Saved File's Path 1bwOm hkS  
private String sFileName; //Saved File's Name ^^ixa1H<  
private int nSplitter; //Count of Splited Downloading File ' S/gmn  
fe_5LC"  
3%b6{ie/=  
public SiteInfoBean() GnJt0{  
{//nSplitter的缺省值为5 G]&qx`TBK  
//default value of nSplitter is 5 nAlQ7 '  
this("","","",5); + mT_QsLEv  
} |+D!= :x  
a9Zq{Ysj  
FfT`;j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .8JTe 0  
{ 88$8d>-  
sSiteURL= sURL; 5\VWCI  
sFilePath = sPath; c@L< Z`u  
sFileName = sName; U|R_OLWAg  
this.nSplitter = nSpiltter; H0vfUF53l  
DkDmE  
l+0oS'`V*L  
} BnF^u5kv%  
8zW2zkv2|#  
Nu)NqFG,  
public String getSSiteURL() =Nr-iae#  
{ g *+>H1}  
return sSiteURL; a/xn'"eli  
} 19%i mf  
\1M4Dl5!  
 _;\_l  
public void setSSiteURL(String value) SNk=b6`9  
{ ysnx3(+|  
sSiteURL = value; ('+d.F[109  
} F#5~M<`.o  
 K_}K@'  
>Y@H4LF;1x  
public String getSFilePath() M x" \5i  
{ z},# ~L6$q  
return sFilePath; jq0O22 -R  
} W: z;|FF  
Q\sK"~@3  
]JQULE)  
public void setSFilePath(String value) $U-0)4yf  
{ vo{--+{ky!  
sFilePath = value; %JTpI`  
} 4 s9LB  
t\O16O7S  
!^G\9"4A  
public String getSFileName() lNO;O}8  
{ C~exi[3  
return sFileName; rEz^  
} :NTO03F7v  
`N8O"UcoBo  
A?OQE9'  
public void setSFileName(String value) &_8 947  
{ }"%N4(Kd  
sFileName = value; M&M 6;Ph  
} _ jlRlt  
|CbikE}kL  
@BMx!r5kn  
public int getNSplitter() goWuw}?  
{ b" [|:F>P  
return nSplitter; #fM`}Ij.A  
} P16~Qj  
VuZr:-K/  
-yNlyHv9  
public void setNSplitter(int nCount) Z0r'S]fe  
{ yEy6]f+>+  
nSplitter = nCount; \o3gKoL%  
} M X]n&  
} K wVbbC3  
t"I77aZ$A  
8zq=N#x  
/* n~Lt\K:  
**Utility.java <IW$m!{VG  
*/ @IZnFHN  
package NetFox; ~pky@O#b  
uCB=u[]y4  
;722\y(Y  
public class Utility { z\4.Gm-  
`uTmw^pZX  
1G`Pmh@  
public Utility() <wHP2|<l*  
{ }Ou}+^Bc  
+LJ73 !  
u)Whr@m  
} 8H`[*|{'  
]hV*r@d  
//线程睡眠 &BSn?  
public static void sleep(int nSecond) :b!s2n!u  
{ X"*5+* z]  
try{ AbOf6%Env  
Thread.sleep(nSecond); RPbZ(.  
} +aAc9'k   
catch(Exception e) 2st3  
{ #B w0,\  
e.printStackTrace (); IdN41  
} U #0Cx-E  
} 0PCGDLk8  
\z)%$#I  
//日志 B`sAk %  
public static void log(String sMsg) ?gXp*>Kg[  
{ a,o*=r  
System.err.println(sMsg); pTuS*MYz  
} QTnP'5y  
ksm~<;td  
e+=K d+:k  
public static void log(int sMsg) iN.n8MN=I  
{ l}P=/#</T  
System.err.println(sMsg); tT._VK]o&R  
} Ew$C ;&9  
} NX&_p!_V  
dQG=G%W  
\ 6MCxh6  
/* bhs _9ivw  
**TestMethod.java .A|@?p[  
*/ :Iz8aQ  
package NetFox;  WfRXP^a  
3iU=c&P  
DW3G  
public class TestMethod { og>uj>H&  
4I(Xy]wm  
!TcJ)0   
public TestMethod() bN=P*hdf  
{ ///xx/weblogic60b2_win.exe [PbOfxxgA  
try{ &6k3*dq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7PF%76TO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,tRj4mx  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fd9k?,zM  
fileFetch.start(); L \iFNT}g`  
} VG~Vs@c(  
catch(Exception e){e.printStackTrace ();} KG{St{uJ  
,iwp,=h=  
=WJ NWt>  
} `QY)!$mUIF  
;GD]dW#  
8JUwf  
public static void main(String[] args) 4`=m u}Y2  
{ |+"(L#wk  
new TestMethod(); ]{>,rK[So  
} U`s{Jm  
} 3=;<$+I6  
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