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http断点续传简单实现(java)

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/* kl3#&>e  
**SiteFileFetch.java &Vnet7LfU  
*/ @iC!Q>D  
package NetFox; 53BXz= k  
import java.io.*; CM9+h;Zm  
import java.net.*; &>L\unS  
'e;*V$+  
[A*vl9=  
public class SiteFileFetch extends Thread { 7lR(6ka&/  
P1Re7/  
EJdq"6S  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3"I 1'+  
long[] nStartPos; //开始位置 *7BY$q  
long[] nEndPos; //结束位置 Q}\,7l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7 &GhJ^Ku  
long nFileLength; //文件长度 _f^q!tP&d  
boolean bFirst = true; //是否第一次取文件 =Q3Go8b4HJ  
boolean bStop = false; //停止标志 <mrLld#_:C  
File tmpFile; //文件下载的临时信息 9DKmXL  
DataOutputStream output; //输出到文件的输出流 $ AG.<  
#\%Gr tM  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) t~sW]<qjp  
public SiteFileFetch(SiteInfoBean bean) throws IOException MT%ky  
{ ,dZ 9=]  
siteInfoBean = bean; <`-"K+e!J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2[j|:Ng7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2/B(T5PY@  
if(tmpFile.exists ()) OEdp:dW|  
{ LEyn1d  
bFirst = false; 0 I;>du  
read_nPos(); "9kEqz4a  
} J +<|8D  
else VR*5}Qp  
{ 7dV^35 KP  
nStartPos = new long[bean.getNSplitter()]; PJO;[: .I  
nEndPos = new long[bean.getNSplitter()]; 0S/&^  
} mUcHsCszH  
L?Wl#wP\;*  
.N/4+[2p(  
/~g M,*  
} R;I}#b cJ  
6<rc]T'|  
!l.Rv_o<O  
public void run() sE>'~ +1_O  
{ z_A%>E4  
//获得文件长度 WYEvW<Hv  
//分割文件 8'`&f &  
//实例FileSplitterFetch Vk0O^o  
//启动FileSplitterFetch线程 b cz<t)  
//等待子线程返回 O!Mm~@MoA  
try{ xv4nYm9  
if(bFirst) z)QyQ  
{ i,;Q  
nFileLength = getFileSize(); }Z0)FU +  
if(nFileLength == -1) -cY /M~  
{ mz9Kwxe  
System.err.println("File Length is not known!"); {D`F$=Dlw  
} ~aA+L-s|  
else if(nFileLength == -2) aW w`v[v  
{ [m}x  
System.err.println("File is not access!"); .Ddl.9p5  
} oY+RG|j@  
else A{&Etu(K  
{ r)U9u 0  
for(int i=0;i<nStartPos.length;i++) ;#r tV;  
{ `z+:Z>>  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  "thfd"-  
} EMs$~CL4  
for(int i=0;i<nEndPos.length-1;i++) BtU,1`El5  
{ LoBKR c2t  
nEndPos = nStartPos[i+1]; aL#b8dCy'  
} B: {bmvy  
nEndPos[nEndPos.length-1] = nFileLength; b-~`A;pr  
} :4(7W[r6  
} e5veq!*C?  
yKDg ~zsh  
2Q1* Xq{  
//启动子线程 Zh3]bg5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3bE^[V8/  
for(int i=0;i<nStartPos.length;i++) VMHiuBz:  
{ $5il]D`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }"q1B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eYsO%y\I  
nStartPos,nEndPos,i); W{ Nhh3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '-W p|A  
fileSplitterFetch.start(); Y;-"Z  
} zg8m(=k'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {/R4Q1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NbkWy  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EWH'x$z_q  
nEndPos = " + nFileLength); 7J$ ^R6rh  
// fileSplitterFetch[nPos.length-1].start(); xvpS%MS  
Oe2Tmvl  
&w/aQs~  
//等待子线程结束 U$0#j  
//int count = 0; r}*2~;:pW  
//是否结束while循环 9H.E15B  
boolean breakWhile = false; u7a4taM$d  
0{AVH/S  
9dKrE_zK:  
while(!bStop) f$(w>B7..  
{ .>CqZN,^  
write_nPos(); {&K#~[)  
Utility.sleep(500); [Hn+r &  
breakWhile = true; p(f)u]1`  
@X1>Wv|[  
"b -KVZ  
for(int i=0;i<nStartPos.length;i++) WGp81DNS|  
{  0m*0I >  
if(!fileSplitterFetch.bDownOver) S1`+r0Fk~n  
{ 0B3*\ H}5  
breakWhile = false; w9.r`_-  
break; Zu~ #d)l3N  
} W e9C9)0  
} mE^6Zu  
if(breakWhile) ''f  
break; A:NsDEt  
7cvbYP\<lv  
hnE@+(d=qJ  
//count++;  $7|0{Dw  
//if(count>4) o`G'E&  
// siteStop(); {#Gr=iv~N  
} <V>vDno\  
tYmWze. j  
[!bTko>rSB  
System.err.println("文件下载结束!"); <niHJ*  
} 3~Ipcr B  
catch(Exception e){e.printStackTrace ();} %li'j|  
} !f7}5/YC7v  
ih1SN,/  
=;@5Ue J  
//获得文件长度 ??1V__w  
public long getFileSize() aEX+M57k~  
{ ?CmW{9O  
int nFileLength = -1; -Frx{3  
try{ 4fpz;2%  
URL url = new URL(siteInfoBean.getSSiteURL()); B.&q]CA v-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z,DEBRT+  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0>E`9|   
WOgbz&S?J  
v\\Z[,dK  
int responseCode=httpConnection.getResponseCode(); ]9A9q<lZ  
if(responseCode>=400) ]^aece t  
{ N],A&}30  
processErrorCode(responseCode); O\lt!p3F  
return -2; //-2 represent access is error K mL PWj  
} 5^P)='0*  
w6#hsRq[C  
hnG'L*HooE  
String sHeader; *W# x#0j  
9>%f99n  
PlBT H  
for(int i=1;;i++) 'SOp!h$  
{ ULQ*cW&;?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ApS/,cV  
//Utility.log(in.readLine()); P8;|>OLZ)  
sHeader=httpConnection.getHeaderFieldKey(i); W@pVP4F0xM  
if(sHeader!=null) 2/>AmVM  
{ VN`2bp>5I  
if(sHeader.equals("Content-Length")) SjG=H%  
{ 6 D~b9 e  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4[+n;OI  
break; CS6,mX  
} B6=8cf"i  
} MdEZ839J  
else roL~r`f`  
break; GH^i,88  
} =_Qt&B)  
} c%i/ '<Afr  
catch(IOException e){e.printStackTrace ();} ogjm6;  
catch(Exception e){e.printStackTrace ();} xN2{Vi{ad  
yrkd#m  
R.> /%o  
Utility.log(nFileLength); p,ZubR J"  
3- LO  
[ &R-YQ@  
return nFileLength; m<"1*d~  
} uX`Jc:1q3  
/ ^!(rHf  
Kw925@W  
//保存下载信息(文件指针位置) DB%=/ \U  
private void write_nPos() Jq?ai8  
{ ##R]$-<4dQ  
try{ Ct"h.rD]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8+gSn  
output.writeInt(nStartPos.length); yUNl)E  
for(int i=0;i<nStartPos.length;i++) \<;/)!Nmw  
{ #T !YFMh;  
// output.writeLong(nPos);  "FG6R'  
output.writeLong(fileSplitterFetch.nStartPos); 0jj }jw  
output.writeLong(fileSplitterFetch.nEndPos); <8j n_6  
} jY$|_o.4  
output.close(); c;(}Ih(#  
} mN ~;MR;  
catch(IOException e){e.printStackTrace ();} }Y<(1w  
catch(Exception e){e.printStackTrace ();} =\oNu&Q^  
} !m]76=@  
d{9jd{ _#G  
Dr`A4LnqY  
//读取保存的下载信息(文件指针位置) PksHq77  
private void read_nPos() @8V8gV? zm  
{ Z>Sv[Ec  
try{  (lt/ t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  !X |Tf  
int nCount = input.readInt(); %T1(3T{Li  
nStartPos = new long[nCount]; t%N#Yh!  
nEndPos = new long[nCount]; NhpGa@[D  
for(int i=0;i<nStartPos.length;i++) n;2W=N?y  
{ !aIIjWz]  
nStartPos = input.readLong(); 2BRY2EF  
nEndPos = input.readLong(); V{c n1Af  
} Udd|.JRd  
input.close(); X*d,z~k%*d  
} 6;5}% B:#h  
catch(IOException e){e.printStackTrace ();} xr.fZMOh4  
catch(Exception e){e.printStackTrace ();} =BNmuAY7  
} #l{qb]n]  
J#'c+\B<2X  
CUY2eQJ{U  
private void processErrorCode(int nErrorCode) 2b3x|9o8  
{ Y}e$5  
System.err.println("Error Code : " + nErrorCode); W)j/[  
} FDpNM\SR1l  
' 71D:%p  
qItj`F)d  
//停止文件下载 b\6w[52m  
public void siteStop() MUVp8! *@  
{ s}/YcUK  
bStop = true; OG}0{?  
for(int i=0;i<nStartPos.length;i++) MPNBA1s  
fileSplitterFetch.splitterStop(); 'B6D&xn'%&  
8 I,(\<Xv  
"64pVaT4  
} %o*afd  
} >W 8!YOc  
//负责部分文件的抓取 .X YSO  
**FileSplitterFetch.java [+ 1([#  
*/ )mp0k%  
package NetFox; uXtfP?3Vy  
=C5 [75z#+  
[(UQQa=+  
import java.io.*; uw;s](~E  
import java.net.*; 8 rnr>Ee@  
"f5u2=7 }  
zBqr15  
public class FileSplitterFetch extends Thread { 3$WK%"%T  
C.(<KV{b  
,!u^E|24  
String sURL; //File URL #YhKAG@|  
long nStartPos; //File Snippet Start Position .KK"KO5k  
long nEndPos; //File Snippet End Position :t9(T?2  
int nThreadID; //Thread's ID tA'i-D&  
boolean bDownOver = false; //Downing is over <>2QDI6_  
boolean bStop = false; //Stop identical h`Y t4-Y  
FileAccessI fileAccessI = null; //File Access interface /T*{Mo{B  
RI-whA8+  
o$Hc5W([Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DHm$gk  
{ v)rN] b]  
this.sURL = sURL; sOVaQ&+y  
this.nStartPos = nStart; Lf7iOW9U3  
this.nEndPos = nEnd; ,]20I _  
nThreadID = id; x{RTI#a.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $"x(:  
} dp_J*8  
oLBpG1Va  
5%,n[qj4IT  
public void run() .DCp)&m l;  
{ }RW4  
while(nStartPos < nEndPos && !bStop) $F\&?B1.  
{ %Sxy!gGz%%  
#`}g?6VHo  
P,tN;c  
try{ | ql!@M(p  
URL url = new URL(sURL); vT3LhN+1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YQe @C  
httpConnection.setRequestProperty("User-Agent","NetFox"); LOe!qt\&  
String sProperty = "bytes="+nStartPos+"-"; 4Mg09  
httpConnection.setRequestProperty("RANGE",sProperty); uodO^5"-  
Utility.log(sProperty); 1gH5#_ ?  
%3"3OOT7  
V}@c5)(j  
InputStream input = httpConnection.getInputStream(); E2%7v  
//logResponseHead(httpConnection); H$\?D+xlf  
hoSk  
QIo|t!7F  
byte[] b = new byte[1024]; kZF\V7k  
int nRead; 2c9@n9Vx3a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {zmo7~=  
{ qY#*zx  
nStartPos += fileAccessI.write(b,0,nRead); ^W#[6]S  
//if(nThreadID == 1) @yobT,DXi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XTHrf'BU  
} :GGsQ n  
K\n %&w  
0Wv9K~F  
Utility.log("Thread " + nThreadID + " is over!"); Tz%l 9aC  
bDownOver = true; LhV4 ^\+  
//nPos = fileAccessI.write (b,0,nRead); j>0S3P,  
} G|Q}.v  
catch(Exception e){e.printStackTrace ();} F-_RL-hbN%  
} 0@3g'TGl  
} -c|O!Lc-  
@{t^8I#]  
7+=j]+O  
//打印回应的头信息 MS,H12h  
public void logResponseHead(HttpURLConnection con) bYG}CO  
{ L\hPw{)  
for(int i=1;;i++) `1pri0!  
{ o&I 0*~ sN  
String header=con.getHeaderFieldKey(i); y]cx}9~  
if(header!=null) VVCCPK^<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zIRa%%.i<  
Utility.log(header+" : "+con.getHeaderField(header)); gU+BRTZ&x  
else (Grj_p6O  
break; F \} Kh3  
} zXVQLz5  
} @/|sOF;8W  
MV=.(Zs  
Fi*6ud\n!  
public void splitterStop() r@s, cCK9?  
{ ]l+2Ca:-[j  
bStop = true; ub.pJJlC  
} yu}4L'e  
,{zvGZ|  
MQ,$'Y5~H  
} | b@?]M  
|Zkcs]8M!  
!K`;fp!  
/* Xb6@;G"  
**FileAccess.java vs6`oW"{#  
*//文件访问(定位,写) /Rt/Efu  
package NetFox; YMqL,& Q{1  
import java.io.*; mc9$"  
<-FZ-asem  
E7*1QR{Q  
public class FileAccessI implements Serializable{ ~49+$.2  
Hi.JL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >@]E1Qfe  
RandomAccessFile oSavedFile; ;'p0"\SV  
long nPos; 73N%_8DH  
a.w,@!7  
#gsAwna3  
public FileAccessI() throws IOException 1 4(?mM3   
{ uY'Ib[H  
this("",0); RZ?>>Ll6  
} ?8vjHEE  
_>3GNvS  
G?jY>;P)  
public FileAccessI(String sName,long nPos) throws IOException FVF: 1DT  
{ 2hU4g e?6  
oSavedFile = new RandomAccessFile(sName,"rw"); zxwpS  
this.nPos = nPos; a#G7pZX/I}  
oSavedFile.seek(nPos); 3OM\R%M  
} *?\2Ohp  
_#N~$   
GI6 EZ}.MZ  
public synchronized int write(byte[] b,int nStart,int nLen) [nG/>Z]W  
{ iW |]-Ba\  
int n = -1; Az0Yt31=  
try{ C5XCy%h  
oSavedFile.write(b,nStart,nLen); M~ *E!  
n = nLen; hoU&'P8  
} Rzb663d  
catch(IOException e) t'[vN~I'  
{ JziMjR  
e.printStackTrace (); U/jJ@8  
} +cj NA2@  
u&pLF%'EQ  
pRt )B`#  
return n; gvwR16N  
} @^;\(If2  
uOougSBV,  
45ct*w  
} ^Jc~G~x4*  
uP+ j_is  
'n>|jw)  
/* $g 1p!  
**SiteInfoBean.java  JTz1M~  
*/ q:?g?v  
package NetFox; 0imz }Z]  
uy`U1>  
'# (lq5 c  
public class SiteInfoBean { ?$r+#'asd(  
3&2,[G04  
U ][.ioc  
private String sSiteURL; //Site's URL bF B;N+>  
private String sFilePath; //Saved File's Path xn6E f"  
private String sFileName; //Saved File's Name QjZ}*p  
private int nSplitter; //Count of Splited Downloading File NWoZDsu  
T,H]svN5p  
XP{ nf9&  
public SiteInfoBean() ;gW~+hW^  
{//nSplitter的缺省值为5 {P = {)  
//default value of nSplitter is 5 ybYSz@7  
this("","","",5); MTLcLmdO  
} v,>q]! |a  
br'~SXl  
RA\H?1;8C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e3(0L I  
{ n,AN&BZ  
sSiteURL= sURL; 4)XN1r:  
sFilePath = sPath; lg!1q8  
sFileName = sName; .|iUDp6vz  
this.nSplitter = nSpiltter; T-<^mX[}  
;$|+H"g|  
-u8@ .  
} ?B h}  
Sb,{+Wk  
]8H;LgM2  
public String getSSiteURL() -lAA,}&+!  
{ rylllJz|L:  
return sSiteURL; Gg-<3z  
} ` 0\hm`  
xRaYm  
v`v+M4upC  
public void setSSiteURL(String value) ?]P&3UU>0z  
{ {/ty{  
sSiteURL = value; 71)HxC[6vA  
} 2;kab^iv'  
,,{Uz)>'W6  
:uI}"Bp  
public String getSFilePath() &/7GhZRt  
{ k+s<;{  
return sFilePath; Mq*Sp UR  
} !N)oi $T%  
Qh{=Z^r  
 gu"Agct4  
public void setSFilePath(String value) VvoJ85  
{ uIWCVR8`Y  
sFilePath = value; 1) @Wcc.  
} :X ;8$.z  
4vy!'r@   
Hq%`DWus\  
public String getSFileName() &"L3U  
{ y"){?  
return sFileName; (:hPT-1  
} Gt 2rJ<>  
}. ,xhF[  
3w^q0/ GD  
public void setSFileName(String value) i\`[0dfY  
{ {8UBxFIM(  
sFileName = value; ^U`[P@T  
} 0<^K0>lm p  
Kh5:+n_X  
K zM\+yC  
public int getNSplitter() aV>w($tdd  
{ xDVzHgbf  
return nSplitter; - 6  
} @A yC0}  
mFo6f\DHr`  
Z NuyGo;  
public void setNSplitter(int nCount) 7p~@S4  
{ 2&=;$2?}  
nSplitter = nCount; ]jy6C'Mp  
} QU417EV'  
} PHz/^p3F  
%*/?k~53  
=e ;\I/  
/* 52:oe1-8  
**Utility.java S&R~*  
*/ 1nvs51?H  
package NetFox; 6*]Kow?  
$?'z%a{  
^ S%4R'  
public class Utility { p?d Ma_ g  
v#nFPB=z  
[u-~<80  
public Utility() "5>p]u>  
{ v3hNvcMpf  
*1>XlVx,  
a?D\H5TF-  
} 5g/WQo\  
D6v0n6w  
//线程睡眠 57HMWlg  
public static void sleep(int nSecond) "b} ^ xy  
{ AWf zMJ;VS  
try{ SmtH2%yI  
Thread.sleep(nSecond); q Rtgk  
} .[CXW2k  
catch(Exception e) qdcCX:Z<  
{ d/* [t!   
e.printStackTrace (); w0 "h,{  
} m&; t;&#  
} >~ne(n4qy  
j)J4[j  
//日志 (]iw#m{  
public static void log(String sMsg) h~F uuL  
{ l "d&Sgnj  
System.err.println(sMsg); VF 6@;5p  
} pX!S*(Q{  
;jnnCXp>  
g3Ff<P P  
public static void log(int sMsg) /n:s9eq  
{ > m5j.GP;  
System.err.println(sMsg); /#Ew{RvW'  
} !7}5"j ;A  
} Oys.8%+ P  
Y6g[y\*t  
Que)kjp  
/* SYl :X   
**TestMethod.java v 7Pv&|  
*/ ,Cx5( ~kU  
package NetFox; -/FCd(  
. vYGJ8(P  
8n2* z  
public class TestMethod { LkNfcBa_  
Mu{mj4Y{  
jMd's|#OP  
public TestMethod() k*^.-v  
{ ///xx/weblogic60b2_win.exe ;r`[6[AG  
try{ 9hLPo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;qzCoe  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '6K WobXm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); na/t=<{  
fileFetch.start(); -h.' ]^I  
} La3f{;|u5M  
catch(Exception e){e.printStackTrace ();} 0w(<pNA  
 ~LkReQI  
r^Gl~sX  
} lW7kBCsz#  
@.MM-  
/i$&89yod  
public static void main(String[] args) NO6.qWl  
{ )u[ 2TI1  
new TestMethod(); abI[J]T9G  
} GJ?rqmbL  
} Pyk~V)~M  
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