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http断点续传简单实现(java)

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/* [L m  
**SiteFileFetch.java >U\1*F,Om,  
*/ 9{*$[%d1  
package NetFox; ) kMF~S|H  
import java.io.*; 0RZ[]:(  
import java.net.*; Wn%b}{9Fb  
Cer&VMrQK  
= Ed0vw  
public class SiteFileFetch extends Thread { X 0vcBHh  
;yu#Bs  
J7;8 S  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3xIelTf*  
long[] nStartPos; //开始位置 /7N&4FrG  
long[] nEndPos; //结束位置 }3O 0nab  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qdnwaJ;&  
long nFileLength; //文件长度 {gz-w|7  
boolean bFirst = true; //是否第一次取文件 2A=q{7s  
boolean bStop = false; //停止标志 C'7DG\pr  
File tmpFile; //文件下载的临时信息 r'(*#  
DataOutputStream output; //输出到文件的输出流 `92P~Y~`W  
Gf=3h4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) b(_f{R7PY  
public SiteFileFetch(SiteInfoBean bean) throws IOException do.AesdXaq  
{ ;\g0* b(  
siteInfoBean = bean; "5HSCl$r%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W1Vy5V|M  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); < k?pnBI_  
if(tmpFile.exists ()) vnN 0o5  
{ [KL-T16  
bFirst = false; QHXA?nBX  
read_nPos(); d{J@A;d a  
} +)hxYLk&I  
else uf^HDr r<L  
{ `r'$l<(4WV  
nStartPos = new long[bean.getNSplitter()]; =`ZRPA!aY  
nEndPos = new long[bean.getNSplitter()]; nIr:a|}[  
} =Y-.=}jp;  
bj6;>Ezp3(  
d&* c3F  
S6g_$ Q7  
} ?$K.*])e  
YK\pV'&+  
j1rR3)oP  
public void run() jp;]dyU  
{ 4/ WKR3X  
//获得文件长度 /\{emE\]  
//分割文件 ?9;CC]D  
//实例FileSplitterFetch A$M8w9  
//启动FileSplitterFetch线程 O dbXna  
//等待子线程返回 ff;~k?L  
try{ esiU._:u  
if(bFirst) D0Mxl?S?  
{ uBK0+FLL@  
nFileLength = getFileSize(); ]Twyj  
if(nFileLength == -1) k!ID  
{ oJZxRm[g$t  
System.err.println("File Length is not known!"); '&+]85_&$  
} {O:{F?  
else if(nFileLength == -2) aGd wuD  
{ ur.krsU  
System.err.println("File is not access!"); 78\j  
} +[R^ ?~VK  
else ;X^#$*=Q  
{ OxPl0-]t  
for(int i=0;i<nStartPos.length;i++) &) 64:l&  
{ %JHv2[r^P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @j!(at4B  
} 4fIjVx  
for(int i=0;i<nEndPos.length-1;i++) ^TD%l8o6  
{  )m#Y^  
nEndPos = nStartPos[i+1]; ,k_"T.w  
} BhYvEbt  
nEndPos[nEndPos.length-1] = nFileLength; $%^](-  
} Z($i+L%.  
} {P_i5V?  
\%&A? D  
0 *;i]owV  
//启动子线程 C1fd@6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b}DC|?~M  
for(int i=0;i<nStartPos.length;i++) XG*> yra`  
{ qyxd9Lk1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Gy[anDE&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D>8p: ^3g  
nStartPos,nEndPos,i); `KtP ;nG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); == E8^jYJw  
fileSplitterFetch.start(); Xt:$H6 y  
} lu00@~rx/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?=LT ^Zp`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $/lM %yXe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D;s%cL`  
nEndPos = " + nFileLength); `#' j3,\6  
// fileSplitterFetch[nPos.length-1].start(); pSbtm74  
fgs@oaoZ  
? )h8uf4  
//等待子线程结束 Yn[>Y)  
//int count = 0; c9G%;U)  
//是否结束while循环 [-VK! 9pQ  
boolean breakWhile = false; $OG){'X  
,oUzaEX  
B~E">}=!  
while(!bStop) @dk-+YxG  
{ /{:XYeX  
write_nPos(); %Z4*;VwQ  
Utility.sleep(500); 7~FHn'xt  
breakWhile = true; 4#}aLP  
{:3\Ms#  
HAL\j 5i  
for(int i=0;i<nStartPos.length;i++) &TY74 w*  
{ *RxJ8.G  
if(!fileSplitterFetch.bDownOver) 1a/C(4 _k  
{ 2Mk;r*FT  
breakWhile = false; }LCm_av  
break; <T?-A}0uO  
} 8^^ 1h  
} z\oTuW*B  
if(breakWhile) V'e%%&g~N  
break; Q 8Hl7__^  
PDPK|FU  
@!=Ds'MJC  
//count++; &ocuZ -5`  
//if(count>4) JRi:MWR<r  
// siteStop(); L {P'mG=4  
} p:TE##  
}ymW};W  
Zj!,3{jX^  
System.err.println("文件下载结束!"); p @kRo#~l  
} >t.Lc.  
catch(Exception e){e.printStackTrace ();} {?`7D:]`^  
} =y-yHRC7  
*~g*J^R}  
1&! i:F#  
//获得文件长度 "D8WdV(  
public long getFileSize() ~CT]&({  
{ >G8I X^*sG  
int nFileLength = -1; &:5*^1oP  
try{ L'r&'y[  
URL url = new URL(siteInfoBean.getSSiteURL()); z?<B@\~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lHtywZ@%3  
httpConnection.setRequestProperty("User-Agent","NetFox"); rbnAC*y8'L  
, + G  
Gn=b_!  
int responseCode=httpConnection.getResponseCode(); '=vZAV`  
if(responseCode>=400) ?5J# yn  
{ #lrwKHZ+  
processErrorCode(responseCode); X+ITW#  
return -2; //-2 represent access is error 'bJGQ[c  
} Bkd$'7UT  
w") G:K  
)-_^vB  
String sHeader; ~;3#MAG  
BW7AjtxQ&  
A!Cby!,  
for(int i=1;;i++) !Pw*p*z  
{ |J,zU6t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aSvv(iV  
//Utility.log(in.readLine()); . 2$J-<O  
sHeader=httpConnection.getHeaderFieldKey(i); 5PO_qr= Hx  
if(sHeader!=null) JyZuj>` 6  
{ *0xL(  
if(sHeader.equals("Content-Length")) Vt(Wy  
{ q@~g.AMCB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'KA$^  
break; 4?1Qe\A^  
} '";#v.!  
} f~T7?D0u}N  
else V.&F%(L  
break; e?.j8 Q ~  
} X#ttDB  
} 9 Gd6/2  
catch(IOException e){e.printStackTrace ();} >lV,K1Z  
catch(Exception e){e.printStackTrace ();} salC4z3  
+#MXeUX"  
O3@DU#N&s  
Utility.log(nFileLength); uVUU1@  
vSR&>Q%X  
;:D-}t;  
return nFileLength; 4`Ud\Jm[s  
} ?OFa Q  
3/`BK{  
6 X~><r  
//保存下载信息(文件指针位置) ).;{'8Q  
private void write_nPos() i"}z9Ae~.  
{ ]0."{^ksL  
try{ uK@d?u!`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ob/)f)!!  
output.writeInt(nStartPos.length); y017 B<Ou  
for(int i=0;i<nStartPos.length;i++) 6?F88;L  
{ 4>=M"D hB  
// output.writeLong(nPos); _ l|%~  
output.writeLong(fileSplitterFetch.nStartPos); ~D9Cu>d9  
output.writeLong(fileSplitterFetch.nEndPos); 7A\`  
} o6MFMA+vi  
output.close(); d}4NL:=&  
} :awkhx  
catch(IOException e){e.printStackTrace ();} OP1` !P y  
catch(Exception e){e.printStackTrace ();} ^$: w  
} qR'FbI  
!b+4[ xky  
Zu.hcDw1  
//读取保存的下载信息(文件指针位置) ,!l_  
private void read_nPos() :|s8v2am  
{ zG#5lzIu,  
try{ F,Q;sq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); oRCc8&  
int nCount = input.readInt(); 'nq=xi@RC  
nStartPos = new long[nCount];  Y${'  
nEndPos = new long[nCount]; {!|4JquE_  
for(int i=0;i<nStartPos.length;i++) $XhMI;h  
{ 8X,6U_>#a  
nStartPos = input.readLong(); ~pRgTXbz  
nEndPos = input.readLong(); $(9QnH1KY  
} .2f vRN92  
input.close(); 7<xnE]jdq  
} A4tk</A  
catch(IOException e){e.printStackTrace ();}  pX_#Y)5  
catch(Exception e){e.printStackTrace ();} @wcF#?J  
} ^xa, r#N:V  
@q'kKVJs  
&IQ=M.!r  
private void processErrorCode(int nErrorCode) uI-T]N:W8x  
{ P+j=]Yg  
System.err.println("Error Code : " + nErrorCode); 9~Dg<wQ  
} z ?\it(  
KQPu9f9  
lAU99(GXV  
//停止文件下载 .rtA sbp.!  
public void siteStop() *SNdU^!  
{ (  zo7h  
bStop = true; i=EOk}R  
for(int i=0;i<nStartPos.length;i++) _Q5mPBO  
fileSplitterFetch.splitterStop(); 1(o\GI3:  
LDjtkD.r  
zl1*GVg  
} Xfc$M(a K{  
} m;dwt1'Zw  
//负责部分文件的抓取 >R F|Q  
**FileSplitterFetch.java XZIapT  
*/ '|IcL1c=I  
package NetFox; (!nkv^]  
yNns6  
(t-hi8"  
import java.io.*; 5tlR rf  
import java.net.*; 1tNL)x"w  
iqDyE*a  
"0CFvN'4  
public class FileSplitterFetch extends Thread { =npE?wK  
L0g+RohW  
?),b902C  
String sURL; //File URL +Y 7M7  
long nStartPos; //File Snippet Start Position 7_\sx7h{3  
long nEndPos; //File Snippet End Position Pp_ 4B  
int nThreadID; //Thread's ID A"JdG%t>.h  
boolean bDownOver = false; //Downing is over eg;7BZim{  
boolean bStop = false; //Stop identical EwPrh  
FileAccessI fileAccessI = null; //File Access interface !J7`frv"(  
L )JB^cxf  
y*iZ;Bv j  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException LIID(s!bX  
{  ~71U s  
this.sURL = sURL; ; JkSZs3  
this.nStartPos = nStart; Ce}`z L  
this.nEndPos = nEnd; 8 Rj5~+5  
nThreadID = id; ^@^8iZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;\RV C 7  
} c[Fc3  
_KH91$iW8m  
,R{&x7  
public void run() 60+zoL'  
{ 6^b)Q(Edut  
while(nStartPos < nEndPos && !bStop) 64/ZfXD  
{ *O_fw 0jV  
\L*%?~  
_w\9 \<%  
try{ 6eSo.@*l  
URL url = new URL(sURL); CQWXLQED>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DsHF9Mn  
httpConnection.setRequestProperty("User-Agent","NetFox"); D]@(LbMG4  
String sProperty = "bytes="+nStartPos+"-"; b9j}QK  
httpConnection.setRequestProperty("RANGE",sProperty); ' ##?PQ*u  
Utility.log(sProperty); A^OwT#  
c]9gf\WW  
mo| D  
InputStream input = httpConnection.getInputStream(); 5T;LWS  
//logResponseHead(httpConnection); ahl|N`  
rRe5Q  
f-F=!^.  
byte[] b = new byte[1024]; +VUkV-kP  
int nRead; {lds?AuK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V8n { k'  
{ ,XT,t[w  
nStartPos += fileAccessI.write(b,0,nRead); X?_rD'3  
//if(nThreadID == 1) WzzA:X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \ja6g  
} UXct+l  
.\XRkr'-  
tyR?A>F4  
Utility.log("Thread " + nThreadID + " is over!"); Ub3$`  
bDownOver = true; KtQs uL%  
//nPos = fileAccessI.write (b,0,nRead); IO\1nB$0nb  
} KTm^}')C8  
catch(Exception e){e.printStackTrace ();} Cv,WG]E7(  
} >e Gg 1  
} ` i[26Qb  
1TZ[i  
zb0NqIN:  
//打印回应的头信息 u2#q7}  
public void logResponseHead(HttpURLConnection con) ud/!@WG  
{ v<1@"9EH  
for(int i=1;;i++) 84(Jo_9  
{ .V;,6Vq  
String header=con.getHeaderFieldKey(i); HkD. W6A3  
if(header!=null) MRpMmu  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); + f6LG 0q  
Utility.log(header+" : "+con.getHeaderField(header)); d'_q9uf'  
else $wM..ee  
break; pz^S3fy  
} 1clzDwW  
} \n_7+[=E  
='"Yj  
L0![SE>  
public void splitterStop() [Hx}#Kds  
{ !RKuEg4hQ  
bStop = true; H1-DK+Q:  
} 2U./ Yfk\  
=zn'0g, J4  
dy6zrgxygP  
} 2? E;(]dQ  
1| sem(t  
n{QyqI  
/* ^(;x-d3  
**FileAccess.java o CCtjr  
*//文件访问(定位,写) ROkwjw  
package NetFox; qJ;~ANwt  
import java.io.*; .<t{saToU  
)>ff"| X  
5RLO}Vn]  
public class FileAccessI implements Serializable{ 29:2Xu i  
sPK]:i C  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1sXCu|\q  
RandomAccessFile oSavedFile; "==c  
long nPos; "W5MZ  
 hE:~~ox  
O<vBuD2  
public FileAccessI() throws IOException 9':Ipf&x  
{ G!FdTvx$  
this("",0); n~lB}  
} _h1bVd-  
9'( _*KSH  
}d5]N  
public FileAccessI(String sName,long nPos) throws IOException 0eO!,/  
{ $PM r)U  
oSavedFile = new RandomAccessFile(sName,"rw"); >9w^C1"  
this.nPos = nPos; 0s`6d;  
oSavedFile.seek(nPos); o*$KiD  
} F.TIdkvp  
Jz''UJY/O  
7T[L5-g  
public synchronized int write(byte[] b,int nStart,int nLen) OXLB{|hH80  
{ 2]fTDKh  
int n = -1; tM5(&cQ!d  
try{ z 4}"oQk:r  
oSavedFile.write(b,nStart,nLen); *$7^.eHfdd  
n = nLen; %ZRv+}z  
} Z*Ffdh>*:&  
catch(IOException e) G:e=9qTf  
{ yl>^QMmo  
e.printStackTrace (); -, +o*BP  
} Yh]a4l0  
bAt!S  
ta&z lZt  
return n; hEjvtfM9\-  
} "0!#De  
6ud?US(  
D?ic~-&  
} z\v  
I 6WHC*  
;FlDRDZ%  
/* @IL@|Srs8  
**SiteInfoBean.java y6am(ugE  
*/ Q8HNST($?  
package NetFox; @yGnrfr  
!o| ex+z;  
f.ua,,P.  
public class SiteInfoBean { -~.+3rcZ]  
tic3a1  
j&DlI_  
private String sSiteURL; //Site's URL UVXruH  
private String sFilePath; //Saved File's Path e[k\VYj[  
private String sFileName; //Saved File's Name Fz8& Jn!  
private int nSplitter; //Count of Splited Downloading File WA}'[h   
%w_MRC  
!T`g\za/  
public SiteInfoBean() =0e>'Iw2  
{//nSplitter的缺省值为5 ?o V.SG'  
//default value of nSplitter is 5 fe4/[S{a   
this("","","",5); OY"BaSEOw}  
} 1mgw0QO  
^/2O_C  
[GyPwb-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]@SEOc@ j  
{ (6[<+j&.  
sSiteURL= sURL; 2;:]Q.g  
sFilePath = sPath; uYTyR;a  
sFileName = sName; =2Ju)!%wr  
this.nSplitter = nSpiltter; -X EK[  
34k(:]56|  
:qXREF@h  
} f[zKA{R  
,9|7{j|u  
v 'L"sgW6I  
public String getSSiteURL() !h&h;m/c  
{ 1|*%  
return sSiteURL;  t":^:i'M  
} [9EL[}  
#~*v*F~3  
=]Y'xzJuu  
public void setSSiteURL(String value) D{]w +  
{ 'o]}vyz;  
sSiteURL = value; l7ES*==&@0  
} cmf*BkS  
O,@QGUoA  
F[ ^ p~u{  
public String getSFilePath() ,vi6<C\  
{ (4l M3clF  
return sFilePath; 9Lt3^MKa"  
} YbVZK4  
a6T!)g  
;XY#Jl>tg  
public void setSFilePath(String value) I<lkociUCG  
{ #r&yH^-  
sFilePath = value; \XY2s&"  
} MMRO@MdfV  
i+-Y"vRi  
Gd&G*x  
public String getSFileName() 1g!%ej jd  
{ 1\f8-:C  
return sFileName; .:['&; k  
} eF 8um$t9  
bB.nevb9p  
G* mLb1  
public void setSFileName(String value) o,1Fzdh6(  
{ uN9.U  _  
sFileName = value; arPqVMVr  
} IOUzj{G#  
K!jau|FS  
+/*A}!#v  
public int getNSplitter() '\7&Iz:%  
{ +Y~,1ai 5^  
return nSplitter; 'vIVsv<p  
} T7G{)wm  
6l?KX  
]=^NTm,  
public void setNSplitter(int nCount) z81`Lhg6  
{ %c c<>Hi  
nSplitter = nCount; wd:SBU~f5*  
} vP<8 ,XG  
} \]/ 6>yT  
$_Lcw"xO  
\4q1<j  
/* e3&.RrA  
**Utility.java ZONe}tv:  
*/ VN4H+9E  
package NetFox; & V/t0  
vw q Y;7  
5|[\Se#  
public class Utility { BYDOTy/%nJ  
oX]c$<w5  
X15e~;&  
public Utility() u|8V7*)3  
{ V,9UOC,Gn  
BI)$aR  
ErMA$UkJ  
} My >{;n=}  
W^nG\"T^  
//线程睡眠 0Z[8d0  
public static void sleep(int nSecond) ;(Qm<JAa  
{ 0j~C6 vp  
try{ _EZrZB  
Thread.sleep(nSecond); V@>s]]HMq#  
} `Axn  
catch(Exception e) ab5z&7Re6  
{ {wf e!f  
e.printStackTrace (); [.iz<Yh  
} oxm3R8 S  
} hz+x)M`Y  
OGO4~Up  
//日志 ?Da!QH >,]  
public static void log(String sMsg) 8BJ&"y8H  
{ 3m`y?Dd  
System.err.println(sMsg); l7JY`x  
} V-iY2YiR  
|4FvP R [  
*FUbKr0  
public static void log(int sMsg) j1,ir  
{ V5LzUg]  
System.err.println(sMsg); Vz&!N/0i  
} ygp NMq#?X  
} NvfQa6?;  
0l ]K%5#  
Y;XEC;PXD  
/* S(*SUH  
**TestMethod.java O%kX=6  
*/ Xn3Ph!\Z5e  
package NetFox; gg%OOvaj5  
O}#h^AU-BS  
] Vbv64M3  
public class TestMethod { F .JvMy3  
O9W|&LAL  
"h}miVArS  
public TestMethod() }%9A+w}o  
{ ///xx/weblogic60b2_win.exe Lm}:`  
try{ RI_3X5.KQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =sW(2Im  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); e'zG=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wg=ge]E5  
fileFetch.start(); e[7n`ka '  
} T/&4lJ^2l^  
catch(Exception e){e.printStackTrace ();} {aWTT&-N  
q>*+.~  
]MP6VT  
} @ zE>n  
x;Jy-hMNl  
xV4 #_1(  
public static void main(String[] args) _ZfJfd~  
{ y++[:M  
new TestMethod(); auTApYS53  
} Z;QbqMj  
} i 7 f/r.  
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