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http断点续传简单实现(java)

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/* fCw*$:O  
**SiteFileFetch.java j:,9%tg  
*/ 91Z'  
package NetFox; Vzg=@A#  
import java.io.*; }m- "8\_D  
import java.net.*; I G ~`i I  
-_N)E ))G  
;9a 6pz<  
public class SiteFileFetch extends Thread { `]i []|  
i=S~(gp  
vB0RKk}d5  
SiteInfoBean siteInfoBean = null; //文件信息Bean .; Q:p*  
long[] nStartPos; //开始位置 `3c CH  
long[] nEndPos; //结束位置 uLR<FpM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5's~>up&  
long nFileLength; //文件长度 l'[A? %L%{  
boolean bFirst = true; //是否第一次取文件 pG3k   
boolean bStop = false; //停止标志 g>JLDQdc  
File tmpFile; //文件下载的临时信息 ;i<jhNA  
DataOutputStream output; //输出到文件的输出流 j5$GFi\kB  
o\VUD  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) I/6)3 su%  
public SiteFileFetch(SiteInfoBean bean) throws IOException N2C7[z+l`  
{ $IQw=w7 p  
siteInfoBean = bean; U/ od~29  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fmX!6Kv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8\.b4FNJ  
if(tmpFile.exists ()) Yk!/ow@.  
{ tc+WWDP#"  
bFirst = false; I\O\,yPhhP  
read_nPos(); a_~=#]a  
} k[j90C5  
else zUJZ`seF  
{ <y.]ImO  
nStartPos = new long[bean.getNSplitter()]; ;&b.T}Nf06  
nEndPos = new long[bean.getNSplitter()]; Q\ppfc{,  
} C1kYl0 zR[  
<ABX0U[*  
/YAJbr  
+0Q,vK#j^  
} Fh$slow4!  
Lh.b 5Q|  
zi9[)YqxPH  
public void run() g4p  
{ RE2&mYt  
//获得文件长度 6w8" >~)Z  
//分割文件 e'%v1-&sP  
//实例FileSplitterFetch "qz3u`[o  
//启动FileSplitterFetch线程 (t+;O;  
//等待子线程返回 ZBT1Y.qA  
try{ 46@{5)Tq  
if(bFirst) 'k0[rDFc#3  
{ Pz*_)N}j >  
nFileLength = getFileSize(); /AY4M;}p  
if(nFileLength == -1) :KJ pk:<  
{ 'xY@x-o  
System.err.println("File Length is not known!"); !E8X~DJ  
} Yb3mP!3q8Z  
else if(nFileLength == -2) GzXUU@p  
{ ^!<dgBNj  
System.err.println("File is not access!"); nAIo{ F  
} s#~GH6/  
else YHkcWz  
{ E>'a,!QPv  
for(int i=0;i<nStartPos.length;i++) c/N@zum,{  
{ 9I27TKy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sV"UI  
} Q_-_^J  
for(int i=0;i<nEndPos.length-1;i++) _|[UI.a  
{ y$FW$Ka  
nEndPos = nStartPos[i+1]; ajR%c2G;  
} 2WX7nK;I  
nEndPos[nEndPos.length-1] = nFileLength; J]l rS  
} nRL. ppUI  
} x+ncc_2n&D  
M5nWVK7c  
B~]5$-  
//启动子线程 Qd}m`YW-f$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7w,FX.=;cv  
for(int i=0;i<nStartPos.length;i++) DI+]D~N  
{ d@`M CchCB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), voP7"Dl[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wN1niR'  
nStartPos,nEndPos,i); |8> 3`w!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dI&!e#Y  
fileSplitterFetch.start(); j`^$#  
} $vC1 K5sLk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), QO;N9ZI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zJP6F.Ov!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X[`bMa7IB(  
nEndPos = " + nFileLength); b2aF 'y/  
// fileSplitterFetch[nPos.length-1].start(); EVp,Q"V]  
`>0MNmu  
B`*ZsS=R-  
//等待子线程结束 p&+;w  
//int count = 0; 5^']+5_vb  
//是否结束while循环 fVb-$  
boolean breakWhile = false; eSWL rryY  
(py]LBZ  
w0w G-R ?  
while(!bStop) +fvaUV_-  
{ FZ!`B]]le,  
write_nPos(); H 0+dV3  
Utility.sleep(500); \fA{1  
breakWhile = true; bM8If"  
7VcmVq}X  
=mA: ctu~v  
for(int i=0;i<nStartPos.length;i++) S*j6OwZ  
{ IDnC<MO>  
if(!fileSplitterFetch.bDownOver) 'smWLz}  
{ /}Jj  
breakWhile = false; ono4U.C9  
break; 3a.kBzus  
} :Y9NLbv  
} 'F>'(XWWQ  
if(breakWhile) zSo)k~&[3  
break; Q+4Xs.#  
kOI t(e  
_g1b{$  
//count++; 6-?66g mT  
//if(count>4) K>*a*[t0Sy  
// siteStop(); V&-~x^JK  
} J7r|atSk  
fS~;>n%R  
/rUo{j  
System.err.println("文件下载结束!"); PaV-F_2  
} ,-7R(iMd  
catch(Exception e){e.printStackTrace ();} =-_B:d;  
} m(pE5B(  
EwOV;>@T?  
7 S?4XyU/o  
//获得文件长度 \[Z?&  
public long getFileSize() `rf_7  
{ +$oF]OO  
int nFileLength = -1; @V03a )6,h  
try{ Eb=}FuV  
URL url = new URL(siteInfoBean.getSSiteURL()); XC.%za8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @|Rrf*J?%  
httpConnection.setRequestProperty("User-Agent","NetFox"); \ Y"Wu  
2WU@*%sk"  
/yM:| `tT  
int responseCode=httpConnection.getResponseCode(); m1Y >Nj[f  
if(responseCode>=400) ~gGZmT b  
{ 4 :U?u  
processErrorCode(responseCode); _i/t?7  
return -2; //-2 represent access is error _YF%V;X  
} 6/rFHY2q  
9K9DF1SOa  
=i~}84>  
String sHeader; a'z)  
+nJUFc  
:=J,z,H_U  
for(int i=1;;i++) =$]uoA  
{ d/i`l*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &197P7&o  
//Utility.log(in.readLine()); =}.EY iD  
sHeader=httpConnection.getHeaderFieldKey(i); m 9/}~Y#k  
if(sHeader!=null) m=YU2!Mb  
{ qK)73eNSR  
if(sHeader.equals("Content-Length")) 66fO7OJs  
{ ~8lwe*lNV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r/SG 4  
break; D9z|VIw8  
} r#XT3qp$d  
} 9uGrk^<t  
else qAw x2fPu  
break; fFc/ d(  
} wXsmn1w9  
} ~R(%D-k  
catch(IOException e){e.printStackTrace ();} LqA@&H  
catch(Exception e){e.printStackTrace ();} eut-U/3:#  
l5"OIq  
V O3x~E  
Utility.log(nFileLength); 8QM(?A  
q5?# 3T=  
JU4q zi  
return nFileLength; t+eVR8  
} l8?>>.<P=  
2$Tj84'X  
%Ah^E$&n2  
//保存下载信息(文件指针位置) y3h/ IpT  
private void write_nPos() V3"=w&2]K  
{ 5=f|7yl  
try{ ELj\[&U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z_|/5$T>U  
output.writeInt(nStartPos.length); ,lyb!k8  
for(int i=0;i<nStartPos.length;i++) }`@728E  
{ lyGhdgWc  
// output.writeLong(nPos); JYTP 2  
output.writeLong(fileSplitterFetch.nStartPos); ,G2TVjz  
output.writeLong(fileSplitterFetch.nEndPos); 2sJ(awN>  
} 92 [; Y  
output.close(); 0zi~p>*nJC  
} $C `;fA  
catch(IOException e){e.printStackTrace ();} >(;{C<6|^  
catch(Exception e){e.printStackTrace ();} /oriW;OF  
} ;72T|e  
~-I +9F  
%HL*c =  
//读取保存的下载信息(文件指针位置) ll C#1  
private void read_nPos() nVi[  
{  jrS[f  
try{ 1&- </G#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )'~6HO8Z  
int nCount = input.readInt(); ={z*akn,  
nStartPos = new long[nCount]; RRI"d~~F6  
nEndPos = new long[nCount]; {HCz p,Y  
for(int i=0;i<nStartPos.length;i++) a]MX)?  
{ ?#45wC  
nStartPos = input.readLong(); 7Zh~lM  
nEndPos = input.readLong(); |>#{[wko  
} f\jLqZY  
input.close(); G%s 2P.cd  
} Iu <?&9t  
catch(IOException e){e.printStackTrace ();} mVy|{Oh  
catch(Exception e){e.printStackTrace ();} ]bK=FIK2  
} QnJZr:4b  
2K3{hxB  
8p:j&F  
private void processErrorCode(int nErrorCode) D ^x-^6^  
{  w/kt3Lw  
System.err.println("Error Code : " + nErrorCode); ](s'L8 (x  
} 6*3.SGUY  
RS^lKJ1 U  
q,+yqrt  
//停止文件下载 eN^qG 42  
public void siteStop() M#8uv-L  
{ ;S>])5<  
bStop = true; (Kv#m 3~  
for(int i=0;i<nStartPos.length;i++) [xGf,;Z  
fileSplitterFetch.splitterStop(); 7eiV{tYF  
%;rHrDP(>  
Wh.?j>vB  
} |b)Y#)C;  
} tfGHea)M  
//负责部分文件的抓取 !s&NT @ S  
**FileSplitterFetch.java <UQe.K"  
*/ !Y[lQXv  
package NetFox; XR;eY:89  
N9v1[~ bv_  
]VD|xm:kj  
import java.io.*; [_}J F}6  
import java.net.*; W#hj 1  
=,UWX3`f  
Y$?9Zkp>  
public class FileSplitterFetch extends Thread { LL3#5AA"k|  
"*Tb" 'O  
v uoQz\  
String sURL; //File URL hBBUw0"  
long nStartPos; //File Snippet Start Position 6,0_)O}\b  
long nEndPos; //File Snippet End Position 5Er2}KZJv,  
int nThreadID; //Thread's ID L{8xlx`  
boolean bDownOver = false; //Downing is over E6pMT^{K  
boolean bStop = false; //Stop identical 9T*v9d  
FileAccessI fileAccessI = null; //File Access interface DKBSFm{~Q  
<=>=.kmGt  
s;6CExH  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException * /:x sI  
{ l p(8E6  
this.sURL = sURL; }Nf%n@  
this.nStartPos = nStart; H{=21\a\  
this.nEndPos = nEnd; uLWh |   
nThreadID = id; E(Z8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mD^ jd+  
} D?NbW @]  
#6CC3TJ'k  
 [D<1 CF  
public void run() C,NJb+J  
{ BS:+~|3w  
while(nStartPos < nEndPos && !bStop) 7eV di*  
{ ;e1ku|>$  
U 15H2-`  
<|SRe6m  
try{ ;{U@qQD7  
URL url = new URL(sURL); ]3X@_NYj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oyYR-4m\  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~2gG(1%At9  
String sProperty = "bytes="+nStartPos+"-"; %3ICI  
httpConnection.setRequestProperty("RANGE",sProperty); 1f":HnLRM  
Utility.log(sProperty); ]hFW 73FV  
}#&#^ B#?O  
HBu[gh;b  
InputStream input = httpConnection.getInputStream(); ''0fF_P  
//logResponseHead(httpConnection); W7 #9jo  
w tiny,6  
i:OK8Q{VI  
byte[] b = new byte[1024]; 6jC`8l:  
int nRead; Bg|5KOnd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Aj+2;]M  
{ Y07ZB'K  
nStartPos += fileAccessI.write(b,0,nRead); '.81zpff  
//if(nThreadID == 1) SAyufLEv,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @T'i/}nl  
} kNobl  
_s .G  
*%S"eWb  
Utility.log("Thread " + nThreadID + " is over!"); -)RH5WGS  
bDownOver = true; jAm3HI   
//nPos = fileAccessI.write (b,0,nRead); MM x9(`t*.  
} PqiB\~o@Z  
catch(Exception e){e.printStackTrace ();} T^Ze3L]  
} 9Ru8~R/\  
} N<IT w/@^  
$Z\.-QE\  
FXi{87F2  
//打印回应的头信息 Jc|6&  
public void logResponseHead(HttpURLConnection con) ]]oI#*c  
{ VCD:3U 8  
for(int i=1;;i++) 8j=}u/T@F  
{ x6e}( &p*  
String header=con.getHeaderFieldKey(i); tX> G,hw  
if(header!=null) |4uWh  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )C(? bR  
Utility.log(header+" : "+con.getHeaderField(header)); &I (#Wy3  
else hNH'XQxO  
break; YTexv;VNb|  
} \l]DQaOEe  
} tavpq.0O  
Cc%LztP>  
rU2%dkTa  
public void splitterStop() K"4>DaK2P  
{ Zf65`K3  
bStop = true;  D0% Ug>  
} (K)]qNH  
Te<}*qvD  
L>SjllY  
} :n.f_v}6  
j]aoR  
dAkgR~  
/* @jsDq Ln  
**FileAccess.java enSXP~9w  
*//文件访问(定位,写) Z(ACc9k6:'  
package NetFox; bqnNLs<N  
import java.io.*; C ihAU"  
/p+>NZ"b  
@!yMIM%P  
public class FileAccessI implements Serializable{ s3R(vd  
%sX$ nmi3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =p=rg$?  
RandomAccessFile oSavedFile; d\ 1Og\U|A  
long nPos; qT`k*i?  
%Ntcvp)  
N#DYJ-~*  
public FileAccessI() throws IOException &' Ne! o8  
{ b;cdIl!3  
this("",0); C0}IE,]  
} bdF.qO9  
/$'AjIg4:&  
3~ S8!nx  
public FileAccessI(String sName,long nPos) throws IOException :QB<?HaS'  
{ 9&` 2V  
oSavedFile = new RandomAccessFile(sName,"rw"); b/{t|io{  
this.nPos = nPos; .tzG_  
oSavedFile.seek(nPos); :]^P1sH[  
} NT+?  #0I  
QUQu^p  
~XWQhIAM4  
public synchronized int write(byte[] b,int nStart,int nLen) lJis~JLd`  
{ ;[ u%_  
int n = -1; ] 0B2# d  
try{ jkt_5+S  
oSavedFile.write(b,nStart,nLen); 2L} SJUk*  
n = nLen; g#t[LI9(F[  
} }7 c[Q($K  
catch(IOException e) -U/c\-~fU  
{ tjluk  
e.printStackTrace (); +(1zH-^.  
} )XzI #iQ  
<\}KT*Xp  
H P3lz,d  
return n; zN"J}r:  
} Y#lk6  
7U2J xE  
=yyp?WmC8  
} Bb}fj28  
viMzR(JU  
HFaj-~b  
/* T2!6(, s9  
**SiteInfoBean.java K3x.RQQ-  
*/ 7|[mz> "d  
package NetFox; vDxe/x%  
yX0dbW~@y  
8W#heW\-]  
public class SiteInfoBean { .sj^{kGE  
d BJJZ^(  
zOa_X~!@  
private String sSiteURL; //Site's URL V*iH}Y?^p  
private String sFilePath; //Saved File's Path LG1r]2  
private String sFileName; //Saved File's Name )Hk3A$6(  
private int nSplitter; //Count of Splited Downloading File eK!V );  
IuRmEL_Q_  
[ zEUH:9D  
public SiteInfoBean() )_i qAqkS  
{//nSplitter的缺省值为5 vbD{N3p)?n  
//default value of nSplitter is 5 4y'OMRy  
this("","","",5); Wv/%^3  
} ( m:Zk$  
qycI(5S,  
q~vDz]\G  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nC}6B).el  
{ CS=qj-(  
sSiteURL= sURL; }=8B*  
sFilePath = sPath; *]VFvh  
sFileName = sName; bdibaN-h  
this.nSplitter = nSpiltter; CCWg{*og  
`/ q|@B7  
T<w5vqFDu  
} qASqscO  
uec!RKE  
|Clut~G  
public String getSSiteURL() 'Ub g0"F(  
{ HsHB!mQV  
return sSiteURL; \&iP`v`K  
} D0#x Lh  
B&.FO O  
u( wGl_  
public void setSSiteURL(String value) 846$x$G4  
{ y?a Acn$  
sSiteURL = value; 3rcKzS7  
} X90J!  
.D: Z{|.1  
d)R:9M}v  
public String getSFilePath() KB'qRnkc  
{ sPMa]F(  
return sFilePath; P3nb2.  
} N.]qU d  
8qu2iPOcZ  
I S#FiH  
public void setSFilePath(String value) zOqn<Y@  
{ !>e5z|1   
sFilePath = value; 'F _8j;  
} X(\fN[;  
~YRDyQ:%T  
Mc%Nf$XQ  
public String getSFileName() aP8H`^DFX>  
{ pSr{>;bN  
return sFileName; l#H#+*F  
} ]) rrG/3  
'iGzkf}j  
$;/}?QY(  
public void setSFileName(String value) MV\|e1B}  
{ W'.s\e?gh  
sFileName = value; 2#<xAR  
} %d>=+Ds[  
k-HCeZ  
:)_~w4&  
public int getNSplitter() _:-ha?W$;y  
{ LX@/RAd vz  
return nSplitter; L2pp6bW  
} )d$glI+  
kWe{r5C7  
C_n9T{k  
public void setNSplitter(int nCount) 2;^y4ssg  
{ zSSB>D  
nSplitter = nCount; @*Wh  
} .Y3pS/VI  
} z(fAnn T?  
ae*Mf7  
z[cyA.  
/* HKqwE=NZ  
**Utility.java ld^=#]g  
*/ q*7zx_ o  
package NetFox; rSHpS`\ou  
eXK o.JL  
B|4X}*@SX  
public class Utility { )~+e`q  
tvu!< dxZ  
F^5?\  
public Utility() sp5eVAd  
{ NLrPSqz  
OnF3lCmu  
pDh{Z g6t  
} -|Y(V5]  
BVr0Gk  
//线程睡眠 GW$.lo1|)  
public static void sleep(int nSecond) &g.+V/<[  
{ L. EiO({W  
try{ =9z[[dQ|L  
Thread.sleep(nSecond); e#Z$o($t  
} Yb /i{@AJ  
catch(Exception e) tX@_fYb  
{ 59%tXiO  
e.printStackTrace (); wmTq` XH)  
} AwTJJ0>  
} "v`   
Z7_ zMM  
//日志 ~5 *5  
public static void log(String sMsg) 3q'&j, ,^  
{ 2A\,-*pc  
System.err.println(sMsg); W ]Nv33i [  
} .h& .K  
1XnZy5fEo  
baP^<w^  
public static void log(int sMsg) +Wx{:  
{ w^#L9i'v'  
System.err.println(sMsg); fuA&7gNC  
} "7v@Rye  
} 2con[!U  
E6,4RuCK  
ObE,$_ k  
/* ;+tpvnV;]  
**TestMethod.java ~,BIf+ \XF  
*/ :sP!p`dl  
package NetFox; /-qxS <?o  
:LQ5 u[g$\  
K,e w>U  
public class TestMethod { x#Q>J"g  
7yx$N n`(  
>A<bBK#  
public TestMethod() _^ 'I  
{ ///xx/weblogic60b2_win.exe V`RNM%Y  
try{ i@B[ eta  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [ e8x&{L-_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <TE%Prd}`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9{$<0,?  
fileFetch.start(); *0}3t <5  
} ^kgBa27  
catch(Exception e){e.printStackTrace ();} .-IkL |M  
8?i7U<CB  
(&P9+Tl  
} vi|R(&  
kdCP  
v9D22,K-  
public static void main(String[] args) x&`~R>5/  
{ 0k'e:AjP  
new TestMethod(); Ezi-VGjr]  
} IZm(`b;t^  
} ^m /oDB-  
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