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http断点续传简单实现(java)

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/* 41swG  
**SiteFileFetch.java v5i?4?-Z  
*/ =A,32&;@N  
package NetFox; .F=15A  
import java.io.*; a ^+b(&;k  
import java.net.*; ,"/<N*vh  
$;<h<#_n;  
G:qkk(6_#  
public class SiteFileFetch extends Thread { F8 4LMk?U  
g+ `Ie'o<  
dO Y+| P\  
SiteInfoBean siteInfoBean = null; //文件信息Bean MmOGt!}9A  
long[] nStartPos; //开始位置 H9)$ #r6i  
long[] nEndPos; //结束位置 p-U'5<n  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Q$iGpTL  
long nFileLength; //文件长度 }-{l(8-  
boolean bFirst = true; //是否第一次取文件 Hl&]r'bK  
boolean bStop = false; //停止标志 rnxO2   
File tmpFile; //文件下载的临时信息 *(&,&$1K  
DataOutputStream output; //输出到文件的输出流 QsYc 9]:  
L4SvE^2+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) YW"?Fy  
public SiteFileFetch(SiteInfoBean bean) throws IOException fTM^:vkO  
{ h+$1+Es  
siteInfoBean = bean; O'JH= '  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F' ZLN]"{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); uC G^,BQ  
if(tmpFile.exists ()) wxPg*R+t  
{ 8}p5MG  
bFirst = false; hIa@JEIt  
read_nPos(); fw^mjD  
} Uc e#v)  
else #'z\[^vp  
{ w&;\}IS  
nStartPos = new long[bean.getNSplitter()]; nM8aC&Rd\  
nEndPos = new long[bean.getNSplitter()]; nZQZ!Vfj  
} NW=j>7  
xtU)3I=F%  
=_cWCl^5  
iZ[o2Tre  
} K@*m6)  
X4i$,$C  
-tx)7KV-  
public void run() @N.W#<IG  
{ h bj^!0m  
//获得文件长度 Y_PCL9G{p  
//分割文件 LnZz=  
//实例FileSplitterFetch )+w0NhJw  
//启动FileSplitterFetch线程 &nPv%P,e  
//等待子线程返回 F5L/7j<}  
try{ )." zBc#  
if(bFirst) {b/60xl?  
{ 4)9X) Qx  
nFileLength = getFileSize(); a|?CC/Ra  
if(nFileLength == -1) F>A-+]X3o  
{ Jb$PlOQ  
System.err.println("File Length is not known!"); ?Pmj}f  
} TQ@*eoJj  
else if(nFileLength == -2) O0b8wpF f  
{ |c8p{)  
System.err.println("File is not access!"); !9iVe7V  
} 40%p lNPj  
else ? dSrY  
{ &$hfAG]"  
for(int i=0;i<nStartPos.length;i++) f$V']dOj1q  
{ KU33P>a"[k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5bmtUIj  
} AH=6xtS-  
for(int i=0;i<nEndPos.length-1;i++) H3OH  
{ `! m+g0  
nEndPos = nStartPos[i+1]; 4B]8Mp~\aL  
} lt0(Kf g  
nEndPos[nEndPos.length-1] = nFileLength; _Zf1=& U#/  
} D zDt:.JZ  
} m U7Ad"  
>47,Hq:2  
Zb2 B5( 0  
//启动子线程 d:sUh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b@,=;Y)O  
for(int i=0;i<nStartPos.length;i++) C?x  
{ P!bm$h*3?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D"1ciO8^I]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UQW;!8J#R(  
nStartPos,nEndPos,i); nsgNIE{>gO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &2?kD{  
fileSplitterFetch.start(); k_}ICKzw1  
} \UB<'~z6!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sOJ"~p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yMz@-B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Uk*s`Y  
nEndPos = " + nFileLength); (Z`Y   
// fileSplitterFetch[nPos.length-1].start(); kf5921(P  
}P}l4k1W  
kFk+TXLDIt  
//等待子线程结束 \D}/tz5~B  
//int count = 0; nh9K(  
//是否结束while循环 |Z2_1( ku  
boolean breakWhile = false; 2N)vEUyDV  
.WG@"2z|  
pbm4C0W}  
while(!bStop) (\R"v^  
{ #lVVSrF,-  
write_nPos(); CtSAo\F  
Utility.sleep(500); qVM]$V#e  
breakWhile = true; b|fq63ar;  
CB|z{(&N  
i1G}m Yz_  
for(int i=0;i<nStartPos.length;i++) EKoCm)}d  
{ vkR"A\:  
if(!fileSplitterFetch.bDownOver) g?@(+\W  
{ 2,_BO6 !d  
breakWhile = false; =~HX/]zF  
break; )(!vd!p5  
} HDy[/7"  
} MCYrsgg}  
if(breakWhile) V@Po}  
break; a<\m` Es=  
O9>/ WmLe  
jliKMd<?  
//count++; l{y~N  
//if(count>4) 14^t{  
// siteStop(); 7z+NR&' M$  
} t~bjDV^`  
U\b,W&%P  
a{u)~:/G  
System.err.println("文件下载结束!"); MOOL=Um3  
} =n#xnZ3  
catch(Exception e){e.printStackTrace ();} %l5J  
} FNm8j#c~Q  
'rCwPsI&4  
}S42.f.p  
//获得文件长度 Ii,L6c  
public long getFileSize() *?i~AXJm  
{ E&"bgwav{(  
int nFileLength = -1; lFRgyEPH  
try{ #FeM.k6  
URL url = new URL(siteInfoBean.getSSiteURL()); thq(tK7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2#py>rF(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4l z9z>J.V  
L;v#9^Fq  
:/1WJG:!  
int responseCode=httpConnection.getResponseCode(); z1YC%Y|R  
if(responseCode>=400) +i K.+B  
{ @s@r5uR9B  
processErrorCode(responseCode); pG|DT ?  
return -2; //-2 represent access is error `[`eg<xj  
} wRWN]Vo  
EW YpYMkm  
#&$4tTl  
String sHeader; CaK 0o*D  
q`qbaX\J3  
"S6d ^  
for(int i=1;;i++) /dtFB5Z"w  
{ <ZCjQkka>r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); EpPKo  
//Utility.log(in.readLine()); 7<X_\,I  
sHeader=httpConnection.getHeaderFieldKey(i); g.z/%Lp K  
if(sHeader!=null) .PF~8@1ju  
{ 5 kQC  
if(sHeader.equals("Content-Length"))  /pV^w  
{ C/lp Se  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E?%rmdyhL!  
break; z i<C 5E`  
} rw58bkh6  
} .,feRK>3  
else P PmE.%_  
break; >a]{q^0  
} ?|{P]i?)'  
} OCF= )#}qd  
catch(IOException e){e.printStackTrace ();} [_CIN  
catch(Exception e){e.printStackTrace ();} fF<~2MiKw  
UKn>.,  
&(irri_  
Utility.log(nFileLength); joYj`K  
@7.Ews5Mke  
1[mX_ }K  
return nFileLength; wR\%tumk  
} +.gZILw  
PC=b.H8P+W  
$M#G;W5c  
//保存下载信息(文件指针位置) $xNZ.|al  
private void write_nPos() ,D;d#fJ  
{ }eSaF@.  
try{ -PoW56  
output = new DataOutputStream(new FileOutputStream(tmpFile)); arET2(h  
output.writeInt(nStartPos.length); D8G5,s-.  
for(int i=0;i<nStartPos.length;i++) `Z0FQ( r_  
{ AwUcU;"9>  
// output.writeLong(nPos); $CRu?WUS]'  
output.writeLong(fileSplitterFetch.nStartPos); !CY: XQm  
output.writeLong(fileSplitterFetch.nEndPos); d3<7t  
} Qw}uB$S>  
output.close(); 2old})CLJ  
} ,F!zZNW9  
catch(IOException e){e.printStackTrace ();} cY0NQKUk~  
catch(Exception e){e.printStackTrace ();} #;z;8q  
} jH({Qc,97  
Uyj6Ij_Pj)  
Vo"Wr>F  
//读取保存的下载信息(文件指针位置) Nu/wjx$b  
private void read_nPos() ~l+2Z4nV  
{ ]{s0/(EA  
try{ n 9PYZxy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s'b 4Me  
int nCount = input.readInt(); J;|a)Nw  
nStartPos = new long[nCount]; L7;8:^  v  
nEndPos = new long[nCount]; L`NY^  
for(int i=0;i<nStartPos.length;i++) uGOED-@  
{ %PM&`c98z7  
nStartPos = input.readLong(); ct`j7[  
nEndPos = input.readLong(); ~@=(#tO.  
} y)vK=,"  
input.close(); :e /*5ix  
} eu={6/O  
catch(IOException e){e.printStackTrace ();} VK286[[fv  
catch(Exception e){e.printStackTrace ();} : e1kpQ  
} l0 =[MXM4  
UE8j8U'L  
>m]LV}">O  
private void processErrorCode(int nErrorCode) iR?}^|]  
{ )G#mC0?PV  
System.err.println("Error Code : " + nErrorCode); @@JyCUd  
} VWq]w5oQO  
s@Dln Du .  
7UIf   
//停止文件下载 &^2SdF  
public void siteStop() "i#aII+T  
{ -M/j&<;LW  
bStop = true; {ETM >  
for(int i=0;i<nStartPos.length;i++) \~RDvsSD  
fileSplitterFetch.splitterStop(); :of(wZa3Q  
DA1?M'N  
w 5 yOSz  
} Z1#u&oX  
} nr2 Q[9~  
//负责部分文件的抓取 I4W@t4bZ  
**FileSplitterFetch.java 1U% /~  
*/ vJLGy]  
package NetFox; j$K*R."  
w A\5-C7 j  
DQT'OZ :w  
import java.io.*; W1 k]P.  
import java.net.*; c/Xg ARCO  
AtewC Yo  
s$).Z(6  
public class FileSplitterFetch extends Thread { +$|fUn{  
1W\E`)Z}]  
om`T/@_,  
String sURL; //File URL DY -5(6X  
long nStartPos; //File Snippet Start Position #=t/wAE y:  
long nEndPos; //File Snippet End Position MjU|XQS:  
int nThreadID; //Thread's ID  =*&[K^  
boolean bDownOver = false; //Downing is over y(o)} m*0  
boolean bStop = false; //Stop identical w8XCU> |  
FileAccessI fileAccessI = null; //File Access interface =e4 r=I  
I]^>>>p$  
@^A5{qQ\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,Klv[_x7  
{ @^xtxtjzux  
this.sURL = sURL; C,An\lsT  
this.nStartPos = nStart; "!~o  
this.nEndPos = nEnd; [ n7>g   
nThreadID = id; CmZayV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s{-gsSmE  
} I|U'@E  
z Fo11;*D  
f#= c=e-A  
public void run() hbJ>GSoZ,  
{ q0iJy@?A  
while(nStartPos < nEndPos && !bStop) .!x&d4;,q  
{ D7;9D*o\  
M2O_kO eZ  
#;$]M4  
try{ W6&vyOc  
URL url = new URL(sURL); HeOdCr-PN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WwDM^}e  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2yZr!Rb~*  
String sProperty = "bytes="+nStartPos+"-"; :OG I|[  
httpConnection.setRequestProperty("RANGE",sProperty); @1MnJP  
Utility.log(sProperty); Upe}9xf  
`ePC$Ovn  
w G%W{T$  
InputStream input = httpConnection.getInputStream(); V)j[`,M:  
//logResponseHead(httpConnection); zxbf h/=  
X2z<cJG|d@  
v $Iw?y  
byte[] b = new byte[1024]; 4J2^zx,H  
int nRead; KJA :;   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <kak9 6A  
{ JE=t e(a  
nStartPos += fileAccessI.write(b,0,nRead); j3gDGw;  
//if(nThreadID == 1) xu2 KEwgb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T5(S2^)o  
} 2 T!Tiu  
'<R>cN"  
9a}9cMJ^"  
Utility.log("Thread " + nThreadID + " is over!"); Zt`Tg7m  
bDownOver = true; CKYg!\g(:  
//nPos = fileAccessI.write (b,0,nRead); GJ+^t  
} ]~({;;3o-  
catch(Exception e){e.printStackTrace ();} .ZpOYhk  
} :D D<0  
} Qp>leEs]+6  
Wg']a/m  
J ^'El^F  
//打印回应的头信息 Zxa.x?:?n  
public void logResponseHead(HttpURLConnection con) t`Kbm''d[  
{ 6b2UPI7m~  
for(int i=1;;i++) szI7 I$Qb  
{ |9CikLX)7  
String header=con.getHeaderFieldKey(i);  I//=C6  
if(header!=null) g.lTNQm$u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;<[X\;|'  
Utility.log(header+" : "+con.getHeaderField(header)); =]W i aF  
else d*gAL<M7E  
break; i5'&u:  
} j~CnMKN  
} XLN bV?  
{]0e=#hw  
$></%S2g  
public void splitterStop() ?'a8QJo  
{ JMb_00r  
bStop = true; dftBD  
} s]arNaaA  
bSB%hFp=Cp  
SmRlZ!%e  
} 4,9$udiGY  
6Sr]<I +:  
fab'\|Y   
/* ,X4e?$7g  
**FileAccess.java jvzioFCt  
*//文件访问(定位,写) #36Q O  
package NetFox; g^AQBF  
import java.io.*; N[%u>!  
wPA^nZ^}9c  
U7r8FLl  
public class FileAccessI implements Serializable{ PRKZg]?  
o/5-T4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ex3Qbr  
RandomAccessFile oSavedFile; *ByHTd  
long nPos; *rxr:y#Ve  
gFDnt  
NYm"I`5w  
public FileAccessI() throws IOException !`DRJ)h  
{ I \:WD"  
this("",0); <`H0i*|Ued  
} ll:UIxx  
ZnG.::&:  
V Z(/g"9  
public FileAccessI(String sName,long nPos) throws IOException YOCEEh?  
{ $.G 7Vt  
oSavedFile = new RandomAccessFile(sName,"rw"); Dl,QCZeM  
this.nPos = nPos; yI0bSu<j-  
oSavedFile.seek(nPos); 55[ 4)*  
} t@q'm.:uw<  
+H)'(<  
Q8p6n  
public synchronized int write(byte[] b,int nStart,int nLen) .Y)[c. ,j  
{ !Ok(mgV$/  
int n = -1; -YRIe<}E -  
try{ Q$jEmmm%V[  
oSavedFile.write(b,nStart,nLen); Dk1& <} I  
n = nLen; 5!-TLwl`j\  
} Sg#XcTG  
catch(IOException e) n3^(y"q  
{ ho]:)!|VY  
e.printStackTrace (); ui8 Q2{z  
} Y\|#Lu>B  
&C 9hT  
3h@]cWp  
return n; FpoH m%+  
} P4zo[R%4  
LPk@t^[  
l_B735  
} z>x@o}#u\|  
G\.~/<Mg+  
."Ms7=  
/* *S$v SDJCW  
**SiteInfoBean.java JA^o/%a^  
*/ ^X#y'odtbS  
package NetFox; RObnu*  
-<iP$,bq72  
@[GV0*yz$  
public class SiteInfoBean { 6j#JhcS+  
d2\ !tJm  
>{#JIG.  
private String sSiteURL; //Site's URL %#6@PQ[R.  
private String sFilePath; //Saved File's Path fF Q|dE;cF  
private String sFileName; //Saved File's Name TlG>)Z@/  
private int nSplitter; //Count of Splited Downloading File N&9o  1_}  
2HbnE&  
e UPa5{P  
public SiteInfoBean() 9&mSF0q  
{//nSplitter的缺省值为5 bO~y=Pa \  
//default value of nSplitter is 5 mHD_cgKN  
this("","","",5); eP{srP3 9  
} J-W9Bamx  
^-o{3Q(w  
/:dLqyQ_V  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }nmlN  
{ 2YD\KXDo  
sSiteURL= sURL; b@CB +8 $  
sFilePath = sPath; n1[c\1   
sFileName = sName; t],a1I.gk  
this.nSplitter = nSpiltter; <_?zln:4.  
j,IRUx13f  
!MbzFs~  
} [%W'd9`>  
Qg>NJ\*Q  
STKL  
public String getSSiteURL() 2TK \pfD  
{ %? ~'A59  
return sSiteURL; &@=Jm /5  
} }=R]<`Sj.j  
\#sD`O  
05UN <l]  
public void setSSiteURL(String value) q0sf\|'<}  
{ dFg>uo  
sSiteURL = value; *TOdIq&z  
} sXLW';Fz  
>.:+|Br`  
n@p]v*  
public String getSFilePath() 9QZaa(vN  
{ lu utyK!  
return sFilePath; qF)J#$4;6  
} u?').c4  
awLvLkQb{  
a~o <>H  
public void setSFilePath(String value) XF`2*:7  
{ A(Ct^/x-  
sFilePath = value; b?wrOS  
} Dy08.Sss  
b,!C8rJ  
!R{IEray  
public String getSFileName() JsaXI:%1  
{ ':4cQ4Z  
return sFileName; ucCf%T\:  
} ];bRRBEU  
mh+T!v$[n)  
ew;;e|24  
public void setSFileName(String value) mF~T?L"  
{ 7?lz$.*Avp  
sFileName = value; Bk8}K=%w  
} <JPN< Kv  
cXweg;  
,05PYBc3  
public int getNSplitter() y<`5  
{ LKN7L kl  
return nSplitter; @2(u=E:^  
} )"x6V""Rb  
c~|(j \FI  
A|biOz  
public void setNSplitter(int nCount) .:_'l)-  
{  3@Ndn  
nSplitter = nCount; nnlj#  
} Z[O hZ 9  
} eqtZU\GI>  
s.1F=u9a  
m\teE]8x  
/* "O$bq::(]e  
**Utility.java G?4@[m  
*/ O]:9va  
package NetFox; t FU4%c7V  
k@xinK%O{  
EKc<|e,F  
public class Utility { .jRI $vm  
Y1r$;;sH  
1 UQ,V`y  
public Utility() xU'z>y4V$  
{ \p!UY 3'  
y_PA9#v7  
#N{]  
} A %w9Da?B  
fECV\Z  
//线程睡眠 j26i+Z  
public static void sleep(int nSecond) +!).'  
{ \((MoQ9Qk  
try{ Iv6 lE:)  
Thread.sleep(nSecond); (Cr  
} ;<~f-D,  
catch(Exception e) N^ +q^iW  
{ ._+cvXy  
e.printStackTrace (); t{;2$z 0  
} nD i^s{  
} [^!SkQ  
S5>s&  
//日志 !~ o%KQt  
public static void log(String sMsg) [$3+5K#  
{ 2V~E <K-  
System.err.println(sMsg); UfW=/T  
} ]9!y3"..W{  
SIK:0>yK"  
0E\#!L  
public static void log(int sMsg) 7_~sa{1R.  
{ D:`Q\za  
System.err.println(sMsg); Mi]^wCF  
} $(}rTm  
} w_"d&eYdg0  
`2>p#`  
f )Lcs  
/* o Mz{j:  
**TestMethod.java Ry95a%&/s  
*/ XPhP1 ^>\  
package NetFox; Dgz, Uad8f  
8Z !%rS  
,ye}p 1M  
public class TestMethod { )\])?q61  
{@X>!]  
<F^9ML+'  
public TestMethod() $9%F1:u  
{ ///xx/weblogic60b2_win.exe Byq VNz0L  
try{ QC'Ru'8S  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); izSX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~vTwuc\(H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); eEXNEgbn  
fileFetch.start(); cB&_':F  
} -9vNV:c  
catch(Exception e){e.printStackTrace ();} U\%r33L )  
RUY7Y?  
O=__w *<  
} ")KqPD6k  
V u")%(ix  
)\yK61aX  
public static void main(String[] args) 6UCF w>  
{ 0"7+;(\1Rk  
new TestMethod(); 2hV -h  
} s AFn.W  
} :uo)-9_  
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