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http断点续传简单实现(java)

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/* 1$Eiv8xd  
**SiteFileFetch.java foL`{fA  
*/ <JKPtF2b  
package NetFox; }jIb ^|#CD  
import java.io.*; [oKB1GkA  
import java.net.*; tH W"eag  
55,vmDd  
aQRZyE}  
public class SiteFileFetch extends Thread { )'fIrBT  
vo0[Z,aH5  
?d_<S0j-)  
SiteInfoBean siteInfoBean = null; //文件信息Bean aP"i_!\.aa  
long[] nStartPos; //开始位置 f5sk,Z  
long[] nEndPos; //结束位置 (8H^{2K~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8Oc*<^{#  
long nFileLength; //文件长度 F$+_Z~yt3;  
boolean bFirst = true; //是否第一次取文件 =?FA9wm  
boolean bStop = false; //停止标志 F"0 tv$  
File tmpFile; //文件下载的临时信息 %mI`mpf  
DataOutputStream output; //输出到文件的输出流 x6$P(eN  
j&44wuf  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) B\<zU  
public SiteFileFetch(SiteInfoBean bean) throws IOException E )Hp.  
{ wHIS}OONz  
siteInfoBean = bean; aZBaIl6I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'i`;Frmg  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @``!P&h  
if(tmpFile.exists ()) HX<5i>]0\u  
{ nk-?$'i9q  
bFirst = false; 9$)4C|  
read_nPos(); Kt`0vwkjvI  
} ,l@hhaLm?  
else ^8fO3<Jg  
{ W6\s@)b;  
nStartPos = new long[bean.getNSplitter()]; +'lfW{E1t  
nEndPos = new long[bean.getNSplitter()]; z6Mf>q  
} $ Q2|{*  
+,PBhB  
"` 9W"A=  
DrB=   
} &}P62&  
!{ )H  
!hJKI.XH  
public void run() sS+9ly{9J  
{ ]INbRytvc  
//获得文件长度 )IhI~,0Nmj  
//分割文件 9D 0ujup  
//实例FileSplitterFetch \ wnQ[UNjP  
//启动FileSplitterFetch线程 A4SM@ry  
//等待子线程返回 O #0:6QX  
try{ !5{t1 oJ  
if(bFirst) nQ/El&{  
{ o#6j+fo!n  
nFileLength = getFileSize(); UY|nB hL  
if(nFileLength == -1) dc:|)bK M  
{ Ag?@fuk$J  
System.err.println("File Length is not known!"); rV1JJ.I  
} ) tsaDG-E  
else if(nFileLength == -2) yfaXScbE  
{ -M(:z  
System.err.println("File is not access!"); &d6'$h:kHb  
} vU~#6sl  
else }l_) d  
{ 3RGVH,  
for(int i=0;i<nStartPos.length;i++) Nf3Kz#!B  
{ 67J=#%\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rJg! 2  
} &z,w0FOre  
for(int i=0;i<nEndPos.length-1;i++) fe&K2C%bm  
{ lRentNg0b  
nEndPos = nStartPos[i+1]; Kh%9Oy  
} tAaFIIvY  
nEndPos[nEndPos.length-1] = nFileLength; 1UmV &  
} o&X!75^G>  
} 9i9VDk{  
D^f;dT;-  
k^ID  
//启动子线程 3+(Fq5I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sLB{R#Pt  
for(int i=0;i<nStartPos.length;i++) ;pC-0m0Y  
{ P$w0.XZa  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7';PI!$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Jzfz y0$  
nStartPos,nEndPos,i); &)`A4bf%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3Vt-]DGX  
fileSplitterFetch.start(); ?hmj0i;XC  
} A$%%;O   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Grkj @Q*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b-~Gt]%>m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8$@gAlI^  
nEndPos = " + nFileLength); {{giSW'  
// fileSplitterFetch[nPos.length-1].start(); Imi_}NB+  
N{E >R&,q  
{?#g*QF|^  
//等待子线程结束 .F> c Z,  
//int count = 0; fr:RiOPn  
//是否结束while循环 8=<d2u'  
boolean breakWhile = false; t7R;RF  
P\w.:.2  
jJg 'Y:K9q  
while(!bStop) HnU}Lhjzj  
{ |-2,k#|  
write_nPos(); l |\Q~ D!o  
Utility.sleep(500); ^<ayPV)+  
breakWhile = true; kOJs;k  
[UFLL:_sC  
fMhMB |W.  
for(int i=0;i<nStartPos.length;i++) @hg1&pfxZ<  
{ Elm/T]6  
if(!fileSplitterFetch.bDownOver) pdmeB  
{ L?0dZY-"  
breakWhile = false; +D$\^ <#  
break; ^[d)Hk}L  
} .GkH^9THP  
} xS*f{5Hr8  
if(breakWhile) Ugrcy7  
break; Z7OWpujCvN  
5C2 *f 4|  
J[]YG+r  
//count++; .Ml}cE$L  
//if(count>4) Wh 8fC(BE  
// siteStop(); e WcS>N  
} e7 5*84  
"y>l2V,4j%  
-/KVZ  
System.err.println("文件下载结束!"); Fi1gM}>py  
} "(T@*"vX2  
catch(Exception e){e.printStackTrace ();} ;M\H#%G.  
} WG(tt.  
U%j=)VD ])  
O"_FfwO a  
//获得文件长度 ~#@sZ0/<  
public long getFileSize() \ $z.x-U  
{ 3Pkzzyk_|D  
int nFileLength = -1; IjJ3./L!5  
try{ QT^W00h  
URL url = new URL(siteInfoBean.getSSiteURL()); xZbm,. v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \q%li)  
httpConnection.setRequestProperty("User-Agent","NetFox"); H@5:x8  
)2u=U9  
QvjsI;CQ-  
int responseCode=httpConnection.getResponseCode(); U0UOubA  
if(responseCode>=400) =f=MtH?0y  
{ 9C3q4.$D  
processErrorCode(responseCode); +7d%)t  
return -2; //-2 represent access is error |.)dOk,o  
} f; >DM  
7S1 Y)  
9cX ~  
String sHeader; @yS  
r|6S&Ia>  
zVJ wmp^  
for(int i=1;;i++) !<@k\~9^D  
{ 4AzS~5S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WE68a!6  
//Utility.log(in.readLine()); ~vBmW_j  
sHeader=httpConnection.getHeaderFieldKey(i); *W%HTt"N  
if(sHeader!=null) i wQ'=M  
{ vvFXdHP  
if(sHeader.equals("Content-Length")) } 3 RqaIY}  
{ 3($%AGKJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }4  5|  
break; #Ubzh`v  
} O0';j!?X  
} _`*x}  
else >jRz4%  
break; kbBX\*{yh  
} ``$At,m  
} vw>O;u.]B  
catch(IOException e){e.printStackTrace ();} OGrp {s  
catch(Exception e){e.printStackTrace ();} D8C@x`  
n3jA[p:  
UYD(++  
Utility.log(nFileLength); )9{?C4NQ  
=-1d m+P  
O jr{z  
return nFileLength; K{t7_i#tv  
} %AXa(C\1  
$ZH$x3;  
Iy6 "2$%a  
//保存下载信息(文件指针位置) ?_(0cVi  
private void write_nPos() #rF|X6P  
{ rhHX0+  
try{  #/MUiV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8s6[?=nM  
output.writeInt(nStartPos.length); o_vK4%y(  
for(int i=0;i<nStartPos.length;i++) srw5&s(3X  
{ <dLdSEw  
// output.writeLong(nPos); M g1E1kXe  
output.writeLong(fileSplitterFetch.nStartPos); u&m B;:&  
output.writeLong(fileSplitterFetch.nEndPos); `.>2h}op  
} E<>n0",  
output.close(); (Lo<3a-]  
} i/NY86A  
catch(IOException e){e.printStackTrace ();} ;vc$;54K  
catch(Exception e){e.printStackTrace ();} 4%aODr8  
} ? D2:'gg  
2_ <  
B=JeZMn  
//读取保存的下载信息(文件指针位置) `7LN?- T  
private void read_nPos() 4?jXbC k~x  
{ r8pTtf#Q  
try{ ?9i 7w1`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qXn %c"  
int nCount = input.readInt(); M%/ML=eLi  
nStartPos = new long[nCount]; m%X~EwFc.  
nEndPos = new long[nCount]; v1 d]  
for(int i=0;i<nStartPos.length;i++) TGY^,H>J  
{ ]Z&2  
nStartPos = input.readLong(); O|O#T.Tg  
nEndPos = input.readLong(); [Z` q7ddd^  
} +D& W!m  
input.close(); EXK~Zf|&Z  
} 1X.5cl?V  
catch(IOException e){e.printStackTrace ();} &D\~-fOGb  
catch(Exception e){e.printStackTrace ();} <2HI. @^  
} cP`o?:  
&$ia#j{l  
C6Ap  4  
private void processErrorCode(int nErrorCode) jt@k< #h~  
{ gxycw4kz  
System.err.println("Error Code : " + nErrorCode); 5#!pwjt~7  
} -e3m!h  
ygW,4Vz7J  
Mmq{]q~At  
//停止文件下载 B- N  
public void siteStop() Ia*eb%HG  
{ 8B"jvrs  
bStop = true; g|a2z_R  
for(int i=0;i<nStartPos.length;i++) sF :3|Yy0  
fileSplitterFetch.splitterStop(); aF1pq  
Wo<zvut8  
jFZJ #'CNS  
} rQC{"hS1  
} -5l74f!i  
//负责部分文件的抓取 v<,? %(g)7  
**FileSplitterFetch.java qY]IX9'kV  
*/ 'QFf 7A  
package NetFox; ,9^wKS!7$  
Y.Na9&-(  
n{J<7I e"*  
import java.io.*; '-p<E"#4Z  
import java.net.*;  ]O3[Te  
~9#\+[ d_  
X!2/cgU7  
public class FileSplitterFetch extends Thread { CaX&T2(  
 =P\H}?PF  
;,}tXz  
String sURL; //File URL J GnL[9P_  
long nStartPos; //File Snippet Start Position n a])bBn  
long nEndPos; //File Snippet End Position -8X* (7  
int nThreadID; //Thread's ID \/*r45!  
boolean bDownOver = false; //Downing is over ,YX[6eZr  
boolean bStop = false; //Stop identical N93 ZI|T  
FileAccessI fileAccessI = null; //File Access interface kep.+t[  
~v$gk   
Z#IRNFj  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8 C@iD%  
{ x3xBl_t  
this.sURL = sURL;  s de|t  
this.nStartPos = nStart; 9]r6V   
this.nEndPos = nEnd; ZMQSy7  
nThreadID = id; DJr{;t$7~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {wiw]@c8  
} !U>711$  
v?F~fRH  
6H\3  
public void run() .-T^ S"`d|  
{ LSv0zAIe/  
while(nStartPos < nEndPos && !bStop) 0&E{[~Pv  
{ J b Hn/$  
\b?z\bC56  
"yxIaTZu  
try{ @jAuSBy  
URL url = new URL(sURL); 3#}5dO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?u{y[pI6  
httpConnection.setRequestProperty("User-Agent","NetFox");  ~,Ck  
String sProperty = "bytes="+nStartPos+"-"; Ho9 a#9  
httpConnection.setRequestProperty("RANGE",sProperty); /xj^TyWM  
Utility.log(sProperty); SsiAyQ|Ma  
Z6\OkD  
c&z@HEzV7  
InputStream input = httpConnection.getInputStream(); vG`R.  
//logResponseHead(httpConnection); eL[BH8l  
h lD0^8S  
7Rqjf6kX`O  
byte[] b = new byte[1024]; s|.V:%9e  
int nRead; N1`/~Gi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H]K(`)y}4  
{ )<-\ F%&b  
nStartPos += fileAccessI.write(b,0,nRead); k;/U6,LQ*  
//if(nThreadID == 1) @JVax-N  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6 6WAD$8$  
} Ll\y2oJ  
U@yn%k9  
[GJ_]w^}j  
Utility.log("Thread " + nThreadID + " is over!"); #)QR^ss)iw  
bDownOver = true; vzA)pB~;  
//nPos = fileAccessI.write (b,0,nRead); Dp4\rps  
} %GQPiWu  
catch(Exception e){e.printStackTrace ();} nm2bBX,fh  
} m~mw1r  
} ,r!_4|\  
$e1==@ R  
@ eu4W^W  
//打印回应的头信息 6a5 1bj!f  
public void logResponseHead(HttpURLConnection con) |{udd~oE&  
{ Elw fqfO  
for(int i=1;;i++) GawQ~rD  
{ tP8>0\$)  
String header=con.getHeaderFieldKey(i); C qOvVv  
if(header!=null) 0+p <Jc!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `Nmw  
Utility.log(header+" : "+con.getHeaderField(header)); H5j6$y|I|N  
else E Mq P  
break; Li)rs<IX;m  
} o<Hk/e~  
} w}nc^6qH  
VgLrufJ  
#lXwBfBMf  
public void splitterStop() :23w[vt=  
{ ;DbEP.%u$  
bStop = true; xwoK#eC~ F  
} ( `T;nz  
#m [R1G#  
s>hNwb/  
} PoTJ4z  
6wK>SW)#&j  
g93-2k,  
/* ;G_{$)P.o  
**FileAccess.java CR3<9=Lv>  
*//文件访问(定位,写) YQGVQ[P  
package NetFox; I~ Q2jg2  
import java.io.*; ?T]3I.3 2^  
?Co)7}N  
;cKN5#7  
public class FileAccessI implements Serializable{ R"%zmA@o=  
NH+?7rf8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 L|O[u^  
RandomAccessFile oSavedFile; x{y}pH"H  
long nPos; }Fs;sfH  
EY'kIVk  
lr[U6CJY  
public FileAccessI() throws IOException 2H+!78  
{ x-J.*X/aB  
this("",0); !0i6:2nw  
} t&m 8 V$Q  
3[`/rg,  
Yl}'hRp  
public FileAccessI(String sName,long nPos) throws IOException mN+ w,  
{ Uj]Tdg  
oSavedFile = new RandomAccessFile(sName,"rw"); 5qZebD2a  
this.nPos = nPos; zl8O @g  
oSavedFile.seek(nPos); lsJl+%&8  
} 2Iv&XxSo  
vKrOIBP  
K[{hh;7  
public synchronized int write(byte[] b,int nStart,int nLen) dQW=k^X 'U  
{ |qe[`x; %  
int n = -1; G':wJ7[]`  
try{ lRb|GS.h/  
oSavedFile.write(b,nStart,nLen); v0psth?qV  
n = nLen; $aIq>vJO9  
} c:? tn  
catch(IOException e) BJA&{DMHm  
{ [{R^!Az&b<  
e.printStackTrace (); *nZe|)m  
} Wgp}v93  
\piB*"ln  
<K6gzi0fl  
return n; Jkf%k3H3I*  
} LdAWCBLS  
:@x_& b  
 \_GG6  
} :'hc&wk`  
7I\qEr57  
{nQ?+o3  
/* 2H\ }N^;f  
**SiteInfoBean.java  8kn> ?  
*/ aL?+# j^"  
package NetFox; K9z 1'k QH  
6b!F7ky g  
LsW7JIQd  
public class SiteInfoBean { M{(g"ha  
]Q8[,HTG  
(}!xO?NA(  
private String sSiteURL; //Site's URL [Q0n-b,Q  
private String sFilePath; //Saved File's Path Ui:WbH<b{  
private String sFileName; //Saved File's Name 7dxe03h  
private int nSplitter; //Count of Splited Downloading File ohLM9mc9  
,#/%Fn%T  
)-jA4!&  
public SiteInfoBean() >oD,wSYV~  
{//nSplitter的缺省值为5 10gh4,z[  
//default value of nSplitter is 5 X%>n vp  
this("","","",5); -q&K9ZCl `  
} r^g"%nq9/  
9K4]~_%h\  
x`3F?[#l  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?ZF ~U  
{ {e35O(Y  
sSiteURL= sURL; \}Hi\k+h':  
sFilePath = sPath; >_3P6-L>  
sFileName = sName; FGRdA^`  
this.nSplitter = nSpiltter; P]A~:Lj  
+Oxw?`I$  
0gevn  
} '?gF9:  
PH1jN?OEwZ  
>IT19(J;A  
public String getSSiteURL() tZL|;K  
{ s@$SM,tnn  
return sSiteURL; 6x*$/1'M3;  
} 59R%g .2Y  
;:WM^S  
uge~*S  
public void setSSiteURL(String value) yhPO$L  
{ xGkc_  
sSiteURL = value; 6d;_}  
} L>3-z>u,  
#qnK nxD  
/l%+l@  
public String getSFilePath() w/49O;rV  
{ m=K46i+NE  
return sFilePath; vB?(|  
} [gkOwU=?  
Zws[C  
|a|##/  
public void setSFilePath(String value) S Bo i|  
{ 0F5QAR O  
sFilePath = value; a#pM9n~a  
} -J& b~t@  
W Te1E,M  
lj US-6  
public String getSFileName() )x<oRHx]  
{ )k~{p;Ke  
return sFileName; 1m{c8Z.h/d  
} dq4t@:\o0  
6uu49x_^L4  
^1\[hyZ!  
public void setSFileName(String value) hpBn_  
{ A+QOox]<  
sFileName = value; Io*mFa?  
} ~a ]R7X7  
} Q1m  
Fs_zNN  
public int getNSplitter() qK jUp"  
{ aYmN' POi  
return nSplitter; )e?6 Ncy  
} Y$4dqn  
X[E!q$ag  
m\"X%Y#  
public void setNSplitter(int nCount) ?l?_8y/ww  
{ 4_KRH1  
nSplitter = nCount; FdE9k\E#/)  
} d%lwg~@&|5  
} m`!Vryf  
D>6vI  
s~b!3l`gu  
/* @|;XDO`k;  
**Utility.java rx\f:-3g  
*/ '{F Od_uk%  
package NetFox; VthM`~3  
PBY;S G ~  
SrT=XX,  
public class Utility { 6xW17P  
KkPr08  
`]$H\gNI[8  
public Utility() ,AuejMd  
{ /8[T2Z!  
xN>+!&3%w  
FNHJHuTe  
} _OY<Hb3%M  
BnPL>11Y  
//线程睡眠 T,uVt^.R+  
public static void sleep(int nSecond) IuOQX}  
{ FV>xAU$  
try{ IWNIk9T,u  
Thread.sleep(nSecond); 'Im&&uSkr  
} Epm%/ {sHV  
catch(Exception e) &B@qb?UE1  
{ W:y'a3~  
e.printStackTrace (); wpepi8w,  
} $E35 W=~)  
} ;Ebpf J  
,&aD U  
//日志 VCCG_K9'  
public static void log(String sMsg) yiAusl;  
{ lFc4| _c g  
System.err.println(sMsg); z\6/?5D#v  
} k}908%w  
0$I!\y\  
mF@D O$  
public static void log(int sMsg) B[{Ie G'  
{ ;o?Wn=J  
System.err.println(sMsg); l EsE]f  
} I%# e\  
} n,o;:c  
idGhWV'  
F^}n7h=qk  
/* od`:w[2\  
**TestMethod.java Xb5 $ijH  
*/ ;h#nal>w@S  
package NetFox; I.L8A|nZ  
}ej-Lu,b3  
*+>R^\uT  
public class TestMethod { xOXCCf/  
Fwfe5`9'  
+Heen3  
public TestMethod() ^ ^R4%C  
{ ///xx/weblogic60b2_win.exe K0\Wty0  
try{ o](nK5?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i \u"+:j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^`Qh*:T$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &xjeZh4-  
fileFetch.start(); &Vi0.o  
} sAKQ.8$h*  
catch(Exception e){e.printStackTrace ();} }hX"A!0  
t.tdY  
"Qxn}$6-  
} :O{oVR  
aShZdeC*f  
i4*!t.eI  
public static void main(String[] args) 4j h4XdH  
{ m8ydX6~max  
new TestMethod(); lITZ|u  
} ]Zz<9zix  
} *|Fl&`2  
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