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http断点续传简单实现(java)

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/* I-agZag%  
**SiteFileFetch.java OMk5{-8B  
*/ tb?YLxMV  
package NetFox; tDDy]==E  
import java.io.*; G4 G5PXi  
import java.net.*; -{ u*qtp  
N S#TW  
TPE:e)GO  
public class SiteFileFetch extends Thread { b6E<r>q  
*1@:'rJ  
{ BEo &  
SiteInfoBean siteInfoBean = null; //文件信息Bean iBudmT8  
long[] nStartPos; //开始位置 gN {'UDg  
long[] nEndPos; //结束位置 7DlOW1|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7FO'{Qq  
long nFileLength; //文件长度 xmGk*W)P  
boolean bFirst = true; //是否第一次取文件 KS*oxZ  
boolean bStop = false; //停止标志 ]4 (?BJ  
File tmpFile; //文件下载的临时信息 [ $fJRR  
DataOutputStream output; //输出到文件的输出流 ZX~ _g@  
~L7:2weV[  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &:=$wc  
public SiteFileFetch(SiteInfoBean bean) throws IOException  ,YhwpkL  
{ ,%YBG1E[y  
siteInfoBean = bean; I^Z8PEc+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [_xyl e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dGwszziuK  
if(tmpFile.exists ()) ]S 7^ITn  
{ 0J~Qq]g  
bFirst = false; FEz>[#eOX  
read_nPos(); ^nVl (^{  
} _GqS&JHSf  
else n-QJ;37\  
{ eo^/c +FG  
nStartPos = new long[bean.getNSplitter()]; $j)hNWI  
nEndPos = new long[bean.getNSplitter()]; 2AVc? 9@  
} XN,,cU  
F^!mI7Z|(2  
mKq"3 4F  
M`D$!BJr  
} UK*qKj. )  
69#8Z+dw7  
HEA eo!  
public void run() >5T_g2pkv  
{ 9j*0D("  
//获得文件长度 N~ANjn/wL  
//分割文件 +\#Fd  
//实例FileSplitterFetch BKU'`5`  
//启动FileSplitterFetch线程 ~YCuO0t  
//等待子线程返回 fRTo.u  
try{ Mp\<cE  
if(bFirst) 6aOp[-Le  
{ z1,tJH0  
nFileLength = getFileSize(); (bn Zy0  
if(nFileLength == -1) + E"[  
{ \.e4.[%[2-  
System.err.println("File Length is not known!"); #t!}K_  
} 4 c'4*`I  
else if(nFileLength == -2) *@V*~^V"J[  
{ VSOz.g>  
System.err.println("File is not access!"); vuz4qCQ  
} 1@XgTL4  
else z2/!m[U  
{ "Mmf6hu  
for(int i=0;i<nStartPos.length;i++) Y|0ow_oH  
{ [RU NuO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oQ+61!5>  
} L4f7s7rJ  
for(int i=0;i<nEndPos.length-1;i++) o07IcIo  
{ e,A)U5X  
nEndPos = nStartPos[i+1]; YnV/M,U  
} gdj^df+2F  
nEndPos[nEndPos.length-1] = nFileLength; +?`b=6e(`  
} @kD8^,(oH  
} 8(X0 :  
_|isa]u\ z  
wz -)1!  
//启动子线程 TF+ l5fv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |kiJ}oy  
for(int i=0;i<nStartPos.length;i++) EEf ]u7  
{ R_D c)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )"O{D`uX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6&2LWaWMo$  
nStartPos,nEndPos,i); ;)!"Ty|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G5]1s  
fileSplitterFetch.start(); 9 -jO,l  
} {,O`rW_eS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aw}+'(?8]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \Rk$t7ZH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p*;Qz  
nEndPos = " + nFileLength); "EftN5?/  
// fileSplitterFetch[nPos.length-1].start(); qg,Nb  
zXc}W*ymj  
xQt 3[(Z  
//等待子线程结束 a}.Y!O&  
//int count = 0; :\V,k~asl  
//是否结束while循环 ]@xL=%   
boolean breakWhile = false; |Svk^mq  
#A <1aQ  
&A50'8B2A  
while(!bStop) ,&a`d}g&G  
{ "2HY5 AE  
write_nPos(); 4?]oV%aP)  
Utility.sleep(500); T<jfAE  
breakWhile = true; wFlV=!>,  
DOL%'k?B  
P6?0r_Y  
for(int i=0;i<nStartPos.length;i++) !eD+GDgE]  
{ L{ ^4DznI  
if(!fileSplitterFetch.bDownOver) , &' Y  
{ -a) T6:e  
breakWhile = false; hH+bt!aH  
break; _GbE ^  
} Z^tGu7x  
} ged,>  
if(breakWhile) gAE!a Ky  
break; CD?&<NV  
StQ@g  
rH}fLu8,;Q  
//count++; C%H9[%k  
//if(count>4) oK-!(1A-  
// siteStop(); IbdM9qo7  
} A'eAu  
t;Wotfc[#0  
-gKpL\  
System.err.println("文件下载结束!"); h-'wV${b  
} 3;BvnD7  
catch(Exception e){e.printStackTrace ();} VbxAd 2')  
} jL4>A$  
PvOC5b  
P%GkcV  
//获得文件长度 %RFYm  
public long getFileSize() ch,|1}bi  
{ R+. Nn  
int nFileLength = -1; }V^e7d  
try{ WV_`1hZX  
URL url = new URL(siteInfoBean.getSSiteURL()); 52<~K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {^&k!H2  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;mJkqbVol  
8gpBz'/,  
Tt6{WDscZ  
int responseCode=httpConnection.getResponseCode(); r>3^kL5UI  
if(responseCode>=400) nu 7lh6o=  
{ Lpm?# g uR  
processErrorCode(responseCode); b:B [3|  
return -2; //-2 represent access is error T]2U fi.  
} U1^l+G^,~  
k&DGJ5m$.  
!`C?nY  
String sHeader; eti9nPjG  
/VtlG+dLl  
w4OW4J#  
for(int i=1;;i++) UA0tFeH  
{ YmCbxYa7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4_< nQ9K  
//Utility.log(in.readLine()); <P pYl  
sHeader=httpConnection.getHeaderFieldKey(i); .;%q/hP  
if(sHeader!=null) i ^S2%qz  
{ y*KC*/'"  
if(sHeader.equals("Content-Length")) PdM*5g4  
{ '(9YB9 i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]piM/v\  
break; .v7`$(T  
} 6~:+:;  
} >x?2Fz.  
else \L#QR  
break; }*-u$=2  
} 5vGioO  
} Riq|w+Q  
catch(IOException e){e.printStackTrace ();} ]|BojSL_  
catch(Exception e){e.printStackTrace ();} E(/ sXji!  
104!!m  
: ~'Z(-a  
Utility.log(nFileLength); S2}Z&X(  
ZV#$Z  
4@~a<P#  
return nFileLength; afy/K'~  
} SEU\}Ni{  
K!7q!%Ju  
O"QHb|j  
//保存下载信息(文件指针位置) SauHFl8?  
private void write_nPos() zkG>u,B}  
{ 3*2I$e!Jt  
try{ OgTSx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Lv3XYZgW~  
output.writeInt(nStartPos.length); :B+Rg cqi  
for(int i=0;i<nStartPos.length;i++) To^# 0  
{ /THNP 8.  
// output.writeLong(nPos); 6ZTaQPtm  
output.writeLong(fileSplitterFetch.nStartPos); Zr9d&|$  
output.writeLong(fileSplitterFetch.nEndPos); @5GBuu^j  
} @jKDj]\  
output.close(); ,N0uR@GN  
} >Pyc[_j  
catch(IOException e){e.printStackTrace ();} @bY?$fj_u  
catch(Exception e){e.printStackTrace ();} c G*(C  
} 5Fr;  
A~XOK;sB  
>.LgsMRIKi  
//读取保存的下载信息(文件指针位置) RCQAtBd  
private void read_nPos()  /+N|X  
{ >.n;mk  
try{ ennR@pg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?Oqzd$-  
int nCount = input.readInt(); |""=)-5N  
nStartPos = new long[nCount]; ?'Oj=k"c7  
nEndPos = new long[nCount]; QjqBO+  
for(int i=0;i<nStartPos.length;i++) hXPocP  
{ H)`@2~Y  
nStartPos = input.readLong(); 6#O#T;f)  
nEndPos = input.readLong(); /'mrDb_ip  
} =9fEv,Jk  
input.close(); SF"#\{cjj  
} k=ts&9\  
catch(IOException e){e.printStackTrace ();} ;Na^]32  
catch(Exception e){e.printStackTrace ();} PaxK^*  
} AzxL%,_  
"0b?+ 3_{G  
x'zihDOI  
private void processErrorCode(int nErrorCode) 0s )cVYppe  
{ OWZS3Y+  
System.err.println("Error Code : " + nErrorCode); q;ZLaX\bFl  
} RrKfTiK H  
U>in2u 9  
k06xz#pL  
//停止文件下载 Ma>:_0I5  
public void siteStop() 6<<'bi  
{ 5cgo)/3M@}  
bStop = true; )tScc*=8  
for(int i=0;i<nStartPos.length;i++) ))p$vU3  
fileSplitterFetch.splitterStop(); -.^3;-[  
):^ '/e  
}'DC Q  
} C`3V=BB  
} LSSW.Oz2L  
//负责部分文件的抓取 %V31B\]Nz7  
**FileSplitterFetch.java  WN$R[N  
*/ 6zv;lx0<D&  
package NetFox; amMjuyW  
GKiq0*/M  
{=s:P|ah  
import java.io.*; "havi,m  
import java.net.*; ob)Q,;8R  
D DQs42[  
sw[oQ!f  
public class FileSplitterFetch extends Thread { {>wI8  
m"<4\;GK  
1B6C<cL:sU  
String sURL; //File URL 8~.iuFp  
long nStartPos; //File Snippet Start Position ';&0~[R[  
long nEndPos; //File Snippet End Position Q! Kn|mnN  
int nThreadID; //Thread's ID kkT3 wP  
boolean bDownOver = false; //Downing is over kJI3`gS+  
boolean bStop = false; //Stop identical <b6s&"%=  
FileAccessI fileAccessI = null; //File Access interface 7AI3|Ts]p  
J`YnT  
v#iFQVBq  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Cy<T Vk8  
{ L'13BRu`  
this.sURL = sURL; &S<? 07Z  
this.nStartPos = nStart; x)j/  
this.nEndPos = nEnd; I$+%~4  
nThreadID = id; ax<g0=^R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LE8K)i  
} ^eT@!N  
K?9WY ]Ot  
"!xvpsy  
public void run() "EN98^ Sl  
{ UHr {  
while(nStartPos < nEndPos && !bStop) {cmo^~[L$  
{ ok%EqO  
,>&?ty9o  
tvTWZ`  
try{ y*}AX%8`e~  
URL url = new URL(sURL); O|? Z~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?E%U|(S)=L  
httpConnection.setRequestProperty("User-Agent","NetFox"); &aY/eD  
String sProperty = "bytes="+nStartPos+"-"; 5woIGO3X  
httpConnection.setRequestProperty("RANGE",sProperty); KLG6QBkj  
Utility.log(sProperty); 4sj9Z:  
+Y^-e.UO  
'uPxEu4 >4  
InputStream input = httpConnection.getInputStream(); Sc%aJ1  
//logResponseHead(httpConnection); l?})_1v,R  
|.y>[+Qb*  
L& I` #  
byte[] b = new byte[1024]; 4\&H?:c.  
int nRead; ? UxG/]",  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8rGl&  
{ M_qP!+Y  
nStartPos += fileAccessI.write(b,0,nRead); =>HIF#jU  
//if(nThreadID == 1) #D/$6ah~m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); issT{&T  
} -" 2<h:#  
v;K{|zUdB  
RcY6V_Qx  
Utility.log("Thread " + nThreadID + " is over!"); se~ *<5  
bDownOver = true; :|?~B%-p[  
//nPos = fileAccessI.write (b,0,nRead); 5OPS&:  
} ?+bTPl;%'  
catch(Exception e){e.printStackTrace ();} Tf9&,!>V  
} JCM)N8~i  
} Coga-: 2vu  
-;sJ25(  
aw %>YrJ  
//打印回应的头信息 !}iL O0  
public void logResponseHead(HttpURLConnection con) ;X+G6F'  
{ }UyzM y,  
for(int i=1;;i++) h{Oz*Bq  
{ Sja"(sJ  
String header=con.getHeaderFieldKey(i); U,oD44  
if(header!=null) 4aj[5fhb-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t9-_a5>E\}  
Utility.log(header+" : "+con.getHeaderField(header)); F(T=WR].o  
else db{NK wpj'  
break; j%6|:o3G(  
} F6RyOUma  
} M /n[&  
~z\pI|DQ  
L@C >-F|p  
public void splitterStop() #cw! &  
{ WpZy](,  
bStop = true; 6b-  
} ^?H\*N4  
9`ri J4zl  
w k-Mu\  
} L~^e\^sP  
)v*v  
Ln"+nKr  
/* K?z*3^^X;  
**FileAccess.java u+%)JhIp  
*//文件访问(定位,写) W)6U6  
package NetFox; OU0xZ=G  
import java.io.*; ,\|n=T,  
]3gYuz|  
[VfL v.8w  
public class FileAccessI implements Serializable{ I T*fjUY&  
N&R '$w  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U92B+up-  
RandomAccessFile oSavedFile; f9h:"Dnzin  
long nPos; OGSEvfW  
UMHuIA:%U  
m _t(rn~f6  
public FileAccessI() throws IOException |_Naun=+~  
{ 9b{g+lMZo  
this("",0); "2y7&#l   
} iqU.a/~y  
!nP8ysB  
cHqvkN`  
public FileAccessI(String sName,long nPos) throws IOException TzD:bKE&  
{ o=a:L^nt,  
oSavedFile = new RandomAccessFile(sName,"rw"); 7?kXgR[#d  
this.nPos = nPos; #Pe\Z/  
oSavedFile.seek(nPos); kphy7> Km  
} !Szgph"ul  
Li?{e+g  
@Z3[ c[D)9  
public synchronized int write(byte[] b,int nStart,int nLen) &lXx0 "-$  
{ u;l6sdo  
int n = -1; Apw-7*/  
try{ 18[?dV  
oSavedFile.write(b,nStart,nLen); 30gZ_ 8C>}  
n = nLen; C%x(`S^/  
} a=}">=]7  
catch(IOException e) x|~D(zo  
{ `Cb<KAaCH  
e.printStackTrace (); uK"$=v6|  
} ie$fMBIq  
;X9MA=b  
xX/Qoq (}i  
return n; 1*c0\:BQ;z  
} Tko CyD9  
% @^VrhS  
} (GQDJp  
} B?/12+sR  
D6pEQdX`  
0qaG#&!  
/* z- {"pI  
**SiteInfoBean.java 2Wc;hJ.1  
*/ 0X S' v,|  
package NetFox; z9uEOX&2\  
Eo25ir%  
nvUkbmZG#  
public class SiteInfoBean { =8VJ.{xy_e  
o/i5e=9[y  
5 \.TZMB  
private String sSiteURL; //Site's URL N2S!.H!Wz  
private String sFilePath; //Saved File's Path $fU/9jTa  
private String sFileName; //Saved File's Name a*$1la'Uf  
private int nSplitter; //Count of Splited Downloading File aaqjE  
*$WiJ3'(m  
?tal/uC  
public SiteInfoBean() `rOe5Zp$  
{//nSplitter的缺省值为5 ;M(ehX  
//default value of nSplitter is 5 6|(7G64{  
this("","","",5); &bOodkOb  
} +kdU%Sm  
Ff1M~MhG  
*{4{<O<4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sN[@mAoH  
{ >P]I&S-.  
sSiteURL= sURL; #L1yL<'  
sFilePath = sPath; .q;RNCUt  
sFileName = sName; XN0RT>@  
this.nSplitter = nSpiltter; 802]M  
=f{Z~`3  
N;Gf,pE  
} [/2@=Uh-  
0,i+  
-7A!2mRiz  
public String getSSiteURL() A`r$fCt1Vi  
{ (WU~e!}  
return sSiteURL; Z!5m'yZO  
} 5SPl#*W  
*b7 ^s,?  
oVj A$|  
public void setSSiteURL(String value) s-YV_  
{ _o=`-iy9  
sSiteURL = value; \2LA%ZU  
} ^!s}2GcS`  
daokiU+l2  
?_h#>  
public String getSFilePath() f"}14V  
{ d'eM(4R@  
return sFilePath; ,:Y=,[n  
} =S?-=jPtg  
u BW  
Ml_:Q]kl^  
public void setSFilePath(String value) W} +6L|  
{ oY#XWe8Om  
sFilePath = value; IEKX'+t'  
} Z#E#P<&d  
TlZlE^EE<  
6T'43h. :  
public String getSFileName() 3By>t!~Q  
{ "9Fv!*<-W  
return sFileName; @0x.n\M_  
} tGy%n[ \  
cqU/Y_%l'  
\=: g$_l  
public void setSFileName(String value) ;U:o'9^9T  
{ zYl+BM-j,6  
sFileName = value; +Y%I0.?&5  
} ^`C*";8Q  
&wWGZ~T  
/U Rj$ |  
public int getNSplitter() C @[9 LB  
{  9%hB   
return nSplitter; -T="Ml &  
} s_e#y{ {C2  
X]qp~:4G  
kO\&mL& qD  
public void setNSplitter(int nCount) kTe<1^,m  
{ 'bqf?3W  
nSplitter = nCount; <8}9s9Nk  
} T)?@E/VaS  
} WlJRKM2  
<zWQ[^  
Bf}0'MK8zQ  
/* r -DD*'R  
**Utility.java 4xC6#:8  
*/ !P3tTL!*L  
package NetFox; ViC76aJ  
vf'jz`Z  
UgBY ){<  
public class Utility { ,}xC) >  
5Szo5  
HrcnyQ`Q0  
public Utility() l~ >rpG  
{ gA8 u E  
*h8XbBZH  
:zTj"P>"I  
} H H7 gT  
\fGYJ37  
//线程睡眠 9#ay(g  
public static void sleep(int nSecond) < 2r#vmM  
{ <L[)P{jn?p  
try{ $TUC?e9"h  
Thread.sleep(nSecond); mi3q1npb7[  
} 8XXTN@&,  
catch(Exception e) -^%"w  
{ RB 0j!H:  
e.printStackTrace (); = ~R3*GN  
} >?\ !k c  
} O4+w2'.,  
Ki 6BPi^  
//日志 qdnNapWnc  
public static void log(String sMsg) nFOG=>c}  
{ l%V}'6T  
System.err.println(sMsg); X>YOo~yS5  
} wH5O>4LO  
x~I1(l7r  
VY26 Cf"  
public static void log(int sMsg) HCCp<2D"C  
{ gnK!"!nL  
System.err.println(sMsg); IBHG1<3  
} Tl{r D(D  
} )4O`%9=M&  
MjosA R  
:)S4MoG  
/* x{w?X.Nt  
**TestMethod.java %bETr"Xom  
*/ )%W2XvG  
package NetFox; 8U$UI  
jWjK-q@Y  
sm <kb@g  
public class TestMethod { F}mwQ%M  
t$Ji{t-  
Z%d4V<fn  
public TestMethod() ^E,Uc K;  
{ ///xx/weblogic60b2_win.exe aj~@r3E ;  
try{ {?_)m/\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aYX'&k `  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?-p aM5Q+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "K=)J'/n  
fileFetch.start(); bpCe&*\6K  
} Z@Z`8M@Q,  
catch(Exception e){e.printStackTrace ();} .=<pU k 3G  
) FsSXnZL  
$G.|5sEk  
} U9%nku4  
/R?uxhV  
:H k4i%hGk  
public static void main(String[] args) 2Nzcej  
{ -i gZU>0B_  
new TestMethod(); B(NL3WJ  
} p 8rAtz>=J  
} +OP'/  
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