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http断点续传简单实现(java)

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/* u! dx+vd  
**SiteFileFetch.java ixE w!t  
*/ rmr :G  
package NetFox; wSPmiJ/!  
import java.io.*; i'\-Y]?[  
import java.net.*; ?CcX>R-/  
O\)Kg2  
H({m1v ~R  
public class SiteFileFetch extends Thread { /XU=l0u  
bW=3X-)  
'f CSP|  
SiteInfoBean siteInfoBean = null; //文件信息Bean LXPO@2QF  
long[] nStartPos; //开始位置 2A9crL $  
long[] nEndPos; //结束位置 Q>cEG"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $: |`DCC  
long nFileLength; //文件长度 -  eIo  
boolean bFirst = true; //是否第一次取文件 7>0u N|  
boolean bStop = false; //停止标志 )d2:r 07a  
File tmpFile; //文件下载的临时信息 eKZS_Qd  
DataOutputStream output; //输出到文件的输出流 C[d1n#@r  
|f!J-H)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &0fV;%N  
public SiteFileFetch(SiteInfoBean bean) throws IOException # z7yoP  
{ #M5d,%?+#[  
siteInfoBean = bean; 5?([jAOf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w~Nat7nD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Cpy&2o-%v  
if(tmpFile.exists ()) }X/YMgJ  
{ Sw5:T  
bFirst = false; 5HE5$S  
read_nPos(); bOp%  
} D5f[:  
else (h g6<`  
{ ~t ZB1+%)  
nStartPos = new long[bean.getNSplitter()]; dnQ6Ras  
nEndPos = new long[bean.getNSplitter()]; sg49a9`8  
} %r*,m3d  
0Ub'=`]5a  
RDjw|V  
EuImj#Zl  
} He}?\C Bo  
J@}PySq  
^ meU&  
public void run() t%0c$c  
{ Lo5pn  
//获得文件长度 +{C)^!zBK  
//分割文件 d 2^/  
//实例FileSplitterFetch %[M0TE=J  
//启动FileSplitterFetch线程 Gv}Q/v   
//等待子线程返回 H)EL0 Kv/  
try{ 3IB9-wG  
if(bFirst) *X ;ch55\  
{ p . P#S  
nFileLength = getFileSize(); &m   GU  
if(nFileLength == -1) x'..j5  
{ %Lb cwh(9  
System.err.println("File Length is not known!"); l&:8 'k+%=  
} K2e *AE*  
else if(nFileLength == -2) ^u1Nbo  
{ 8#- Nx]VM  
System.err.println("File is not access!"); ! Vlx  
} I,HtW),  
else %lGOExV%  
{ .kMnq8u  
for(int i=0;i<nStartPos.length;i++) !`1m.  
{ >VQLC&u(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); svb7-.!  
} X(rXRP#  
for(int i=0;i<nEndPos.length-1;i++) r>TOJVT&]  
{ 9F?-zn;2s  
nEndPos = nStartPos[i+1]; :@ VCKq!  
} ,S(s  
nEndPos[nEndPos.length-1] = nFileLength; >goHQ30:  
} OLm@-I*  
} n;$u%2t2  
:N"&o(^  
.:B>xg~2  
//启动子线程 );6f8H@G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r<Cr)%z!  
for(int i=0;i<nStartPos.length;i++) AI#.+PrC{/  
{ `wU['{=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _nEVmz!zg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;134$7!Y  
nStartPos,nEndPos,i); \=mLL|a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +zq"dj_  
fileSplitterFetch.start(); 3S2Alx!6  
} (Z[c7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZH8w^}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Il(o[Q>jJ3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 96QY0  
nEndPos = " + nFileLength); #62ThH~  
// fileSplitterFetch[nPos.length-1].start(); o?t H[  
N:k>V4oE  
F4WX$;1  
//等待子线程结束 V45adDiZ  
//int count = 0; @G=7A;-pv0  
//是否结束while循环 G$&jP:2q  
boolean breakWhile = false; \[.qN  
Az8ZA~Op=  
QV:> x#=V  
while(!bStop) "::2]3e  
{ 6NhGTLI  
write_nPos(); %dq%+yw{%m  
Utility.sleep(500); F;h^o!W7r  
breakWhile = true; B)1(  
un -h%-e |  
Ql l{;A  
for(int i=0;i<nStartPos.length;i++) VKX|0~  
{ x=Oy 6"  
if(!fileSplitterFetch.bDownOver) D1v0`od'  
{ "J2q|@.  
breakWhile = false; 5B2p_$W#  
break; jgG9?w)|u  
} 9#&H'mG  
} GiEt;8  
if(breakWhile) W} H~ka  
break; =BE!  
JoiGuZd>  
]&q<O0^'  
//count++; \4G9YK-N>  
//if(count>4) (l-= /6-  
// siteStop(); Zl3e=sg=  
} ~yw]<{?  
~LV]cX2J(  
>dm9 YfQ  
System.err.println("文件下载结束!"); ss-6b^  
} PlLt^q.z[  
catch(Exception e){e.printStackTrace ();} X#JUorGp  
} 0'$67pY  
lN,a+S/'  
r hucBm  
//获得文件长度 Og1vD5a  
public long getFileSize() $ B&Zn Z?  
{ F`x_W;\  
int nFileLength = -1; <f8j^  
try{ z |~+0  
URL url = new URL(siteInfoBean.getSSiteURL()); ~M} K]Li  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h4|}BGO  
httpConnection.setRequestProperty("User-Agent","NetFox"); K[OOI~"C  
M|%bxG^l  
nQ+5jGP1  
int responseCode=httpConnection.getResponseCode(); FjtS  
if(responseCode>=400) jaKW[@<  
{ x< 2]UB`  
processErrorCode(responseCode); R<6y7?]bZ  
return -2; //-2 represent access is error Qg(;>ops  
} M."/"hV`-  
([>__c/Nd  
{4Kvr4)4  
String sHeader; . <z7$lz\  
2(l0Lq*  
"B (?|r%  
for(int i=1;;i++) 3.BUWMD  
{ 7]T(=gg /  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); js <Up/1  
//Utility.log(in.readLine()); @_-,Q5  
sHeader=httpConnection.getHeaderFieldKey(i); >Jx=k"Kv+  
if(sHeader!=null) =d^hiR!GN  
{ \OFmd!Cz  
if(sHeader.equals("Content-Length")) zm5Pl G  
{ ,-E'059  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Komdz/g  
break; }s<;YC  
} ?z l<"u  
} -wV2 79^b  
else ov,s]g83  
break; UhS:tT]7  
} *#Ia8^z=p  
} m+s*Io{Ip  
catch(IOException e){e.printStackTrace ();} 63Gq5dF  
catch(Exception e){e.printStackTrace ();} +ynhN\S$/  
wyB]!4yy,  
eQ#i.%   
Utility.log(nFileLength); >L4F'#I  
8&"Jlz |  
l$9k:#\FD  
return nFileLength; !0Nf`iCQ(  
} u$[8Zmgzz  
GEf=A.WAfw  
v :/!OvLe  
//保存下载信息(文件指针位置) X coPkW  
private void write_nPos() Q> y!  
{ _1G/qHf^S  
try{ ]7W!f 2@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ru*gbv,U  
output.writeInt(nStartPos.length); Pm)*zdZ8  
for(int i=0;i<nStartPos.length;i++) 87l*Y|osP  
{ SQ2v  
// output.writeLong(nPos); mKO~`Wq%@  
output.writeLong(fileSplitterFetch.nStartPos); [5p9p1@u{C  
output.writeLong(fileSplitterFetch.nEndPos); j0{`7n  
} ! Ea!"}  
output.close(); -;_"Y]#  
} 1#_ pj eG  
catch(IOException e){e.printStackTrace ();} 2h51zG#qd  
catch(Exception e){e.printStackTrace ();} s a o&  
} h>GbJ/^  
T{+a48,;  
~<VxtcEBz  
//读取保存的下载信息(文件指针位置) i]k)wr(  
private void read_nPos() /}U)|6- B  
{ H6 x  
try{ T&pCLvkz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W)Y`8&,  
int nCount = input.readInt(); aXVldt'  
nStartPos = new long[nCount]; WcKDerc  
nEndPos = new long[nCount]; \z!lw  
for(int i=0;i<nStartPos.length;i++) `IwZVz  
{ Ii[U%  
nStartPos = input.readLong(); ;u'VR}4ph  
nEndPos = input.readLong(); ^\O*e)#*  
} Y"8@\73(R  
input.close(); MjC<N[WO>N  
} TCyev[(  
catch(IOException e){e.printStackTrace ();} _yN5sLLyb  
catch(Exception e){e.printStackTrace ();} $aJay]F  
} ZXYyG`3+  
T=42]h  
a}NB6E)-  
private void processErrorCode(int nErrorCode) !vu-`u~86  
{ Kj @<$ChZw  
System.err.println("Error Code : " + nErrorCode); Oz-/0;1n  
} V9"R8*@-  
h?n?3x!(  
_%2ukuJ `  
//停止文件下载 &57~i=A 3  
public void siteStop() R)Mkt8v  
{ O[MFp  
bStop = true; RNB&!NC  
for(int i=0;i<nStartPos.length;i++) }9\6!GY0  
fileSplitterFetch.splitterStop(); nN<,rN{ :  
dE,E,tv  
7!jb  
} |Ol29C$@|  
} ^|Fy!kp  
//负责部分文件的抓取 _dk[k@5W{'  
**FileSplitterFetch.java Pa d)|  
*/ vf.MSk?~ar  
package NetFox; Y3[KS;_fr9  
i3|xdYe$  
?y>ji1  
import java.io.*; '1b8>L  
import java.net.*; Bcv{Y\x;ko  
RA<ky*^dr  
WIi,`/K+  
public class FileSplitterFetch extends Thread { VZcW 3/Y  
`(?c4oq,c>  
l]zQSXip  
String sURL; //File URL L1!~T+%uQ  
long nStartPos; //File Snippet Start Position +jB;  
long nEndPos; //File Snippet End Position _w?!Mu  
int nThreadID; //Thread's ID bv]SR_Tiq  
boolean bDownOver = false; //Downing is over nrev!h  
boolean bStop = false; //Stop identical aB;f*x  
FileAccessI fileAccessI = null; //File Access interface s1cu5eCt  
\w1XOm [)  
3h.,7,T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eJ45:]_%I@  
{ N(4y}-w$  
this.sURL = sURL; }gX hN"  
this.nStartPos = nStart; L{jx'[C  
this.nEndPos = nEnd; wMCg`rk  
nThreadID = id; &\6},JN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 aeN #<M&$<  
} 9Xg7=(#  
]}b  
tTTHQ7o*BD  
public void run() |X>'W"Mn  
{ {u y^Bui}  
while(nStartPos < nEndPos && !bStop) b?`2LAgn  
{ =6ru%.8U,  
1gBLJ0q  
$dI mA  
try{ &UnhYG{A  
URL url = new URL(sURL); [5IbR9_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fNAW4I I}  
httpConnection.setRequestProperty("User-Agent","NetFox"); $[`rY D/.  
String sProperty = "bytes="+nStartPos+"-"; F%p DF\  
httpConnection.setRequestProperty("RANGE",sProperty); ["&{^  
Utility.log(sProperty); /Q7q2Ne^*  
aG;F=e  
H:hM(m0?q  
InputStream input = httpConnection.getInputStream(); w`8H=Hf  
//logResponseHead(httpConnection); -V4{tIQY  
P]^OSPRg  
!Q~>)$Cf^  
byte[] b = new byte[1024]; D['J4B  
int nRead; )s:kQ~+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ua|iAD 1  
{ :X}SuM ?c  
nStartPos += fileAccessI.write(b,0,nRead); IYq#|^)5+  
//if(nThreadID == 1) =C,DR4xh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U { 0~&  
} a"YVr'|  
&Cj~D$kDEu  
P,m+^,  
Utility.log("Thread " + nThreadID + " is over!"); 5L2j, ]  
bDownOver = true; I^f|U  
//nPos = fileAccessI.write (b,0,nRead); {"~[F2qR  
} K:< Viz  
catch(Exception e){e.printStackTrace ();} z6J12tu  
} K!ogpd&X&  
} $#n9C79Z@  
IxUj(l1Fm  
oh$"?N7n1  
//打印回应的头信息 :^`j:B  
public void logResponseHead(HttpURLConnection con) n6Uh%rO7S|  
{ c3l(,5DtH  
for(int i=1;;i++) ,sc#l<v  
{ xV+\R/)x  
String header=con.getHeaderFieldKey(i); ?K pDEH~\  
if(header!=null) u{=h%d/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +Eb-|dM  
Utility.log(header+" : "+con.getHeaderField(header)); *LBF+L^C%  
else nkPlfH  
break; \9p.I?=  
} [I%e Ro[  
} W^^0Rh_  
%fS1g Sf h  
".|8(Y  
public void splitterStop() 5|eX@?QF58  
{ J&'*N :d  
bStop = true; m[y~-n  
} .{ILeG  
->51t  
1WqCezI  
} -a_qZ7  
bQI :N  
]7k:3"wH  
/* ~u1~%  
**FileAccess.java <Tgubv+J  
*//文件访问(定位,写) uZ_?x~V/  
package NetFox; H74'I}  
import java.io.*; <?KgzIq2  
cu5}(  
l[5** ?#  
public class FileAccessI implements Serializable{ <astIu Au  
Z)xcxSo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 : ^}!"4{  
RandomAccessFile oSavedFile; Y{e,I-"{  
long nPos; sV5k@1Y  
[V?HK_~  
lrHN6:x(Y4  
public FileAccessI() throws IOException GNmP_N  
{ Em Ut/]  
this("",0); ] g9SUFM  
} q'H6oD`  
LC=M{\  
 K%%Ow  
public FileAccessI(String sName,long nPos) throws IOException 3`SH-"{j%  
{ %jj-\Gz!  
oSavedFile = new RandomAccessFile(sName,"rw"); o-_,l J7o^  
this.nPos = nPos; *$VeR(QN  
oSavedFile.seek(nPos); '.pGkXyQ  
} ]5*H/8Ke7  
-ys/I,}<  
#gWok'ZcR  
public synchronized int write(byte[] b,int nStart,int nLen) t4;gY298  
{ ={o4lFe3v(  
int n = -1; {c?{M.R  
try{ ^|h_[>  
oSavedFile.write(b,nStart,nLen); 2.);OFk+  
n = nLen; &-NGVPk81`  
} ZI$P Qz2i  
catch(IOException e) X0ugnQ6  
{ S]fkA6v  
e.printStackTrace (); }3Ke  
} VrT-6r'Y  
(]mBAQ#hw  
JM0+-,dl[  
return n; Z[z" v  
} c+Z dfdR  
_z]v;Q  
 wDiq~!  
} 0#yH<h$   
?^-fivzS>  
h^IizrqU  
/* Qt'3v"S>)  
**SiteInfoBean.java Tp~Qg{%Og  
*/ Gl{2"!mt=  
package NetFox; &u"mFweS  
z/5TYv)S  
*pS3xit~  
public class SiteInfoBean { %y>*9$<pXe  
'dQGb-<_<  
$i8oLSRV  
private String sSiteURL; //Site's URL %|/\Qu  
private String sFilePath; //Saved File's Path ""V\hHdp  
private String sFileName; //Saved File's Name :& $v.#  
private int nSplitter; //Count of Splited Downloading File I`@>v%0  
H_Hr=_8}-  
}|=Fnyj  
public SiteInfoBean() K43`$  
{//nSplitter的缺省值为5 S9b=?? M)  
//default value of nSplitter is 5 rwwyYIlEg  
this("","","",5); Q-s5-&h(  
} h>xB"E|.  
z:O:g?A  
b4KNIP7E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0lqh;/  
{ l'!_km0{d  
sSiteURL= sURL; %dmQmO,  
sFilePath = sPath; XI ><;#  
sFileName = sName; Bz,Xg-k+  
this.nSplitter = nSpiltter; Y>nQ<  
4|j Pr J  
4rCw#mVtB  
} :=quCzG  
Y.52`s6F  
w1F)R^tU  
public String getSSiteURL() |t$%kpp  
{ [8DPZU@  
return sSiteURL; vls+E o]  
} b\NY!)B  
bWCtRli}  
#'#@H  
public void setSSiteURL(String value) *gwo.s  
{ X"f]  
sSiteURL = value; vvG*DGL)qL  
} Kx;la  
$G /p[JG6-  
{>ghX_m |  
public String getSFilePath() FVOPC:}bj  
{ l~1l~Gx_&n  
return sFilePath; =jG."o  
} )ZZ6 (O  
K[V#Pj9  
|hvclEu,  
public void setSFilePath(String value) xf:|lQf  
{ tOQnxKzu  
sFilePath = value; /I`-  
} >IKIe  
6SAYe%e  
zP!j {y4w  
public String getSFileName() dHn,;Vv^6  
{ R C!~eJG!  
return sFileName; $U^ Ms!'L  
} V1,4M_Z  
xiC.M6/  
@&Af [X4s  
public void setSFileName(String value) ){tT B  
{ gHH[QLD=I  
sFileName = value; IV`+B<3  
} )\izL]=!t  
@zsqjm  
_^0UK|[  
public int getNSplitter() y&F&Z3t  
{ PC?XE8o  
return nSplitter; DnB :~&Dw  
} Qyj:!-o  
0bQ"s*K  
@7?L+.r$9  
public void setNSplitter(int nCount) nG| NRp  
{ |)ALJJ=+  
nSplitter = nCount; ge&!GO  
} v?q)E%5j  
} p" Di;3!y!  
f F9=zrW  
Is  ( Ji  
/* ^"J)^3j<  
**Utility.java :RXzqC  
*/ Lnltt86  
package NetFox; 9iK%@k  
5.U|CL  
0*/[z~Z-1  
public class Utility { QyEoWKu;  
pc](  
`jGG^w3  
public Utility() $)j f  
{ cD<5~`l  
Z~g7^,-t  
#t&L}=G{%  
} ]n4G]ybK%  
5mI}IS|@  
//线程睡眠 5&Le?-/\  
public static void sleep(int nSecond) y>JSo9[@  
{ #<R6!"TNoz  
try{ @aWd0e]  
Thread.sleep(nSecond); 8SO(pw9  
} FlLk.+!t  
catch(Exception e) t\,X G  
{ $_W kI^  
e.printStackTrace (); x?G"58  
} K|wB0TiXP  
} OGnuBK  
%Wg8dy|  
//日志 WP? AQD  
public static void log(String sMsg) 1n>(CwLG"  
{ Wtj* Z.=:  
System.err.println(sMsg); TDW\n  
} v6'k`HnK  
@VKN6yHH  
B d?{ldg  
public static void log(int sMsg) 3TnrPO1E  
{ o;{BI Q1  
System.err.println(sMsg); EpH\;25u  
} n4Q ^   
} yH',vC.  
Sk%*Zo{|  
6F3FcUL  
/* p']oy;t  
**TestMethod.java qbD[<T  
*/ IFW"S fdZk  
package NetFox; :sJQ r._L  
$36.*s m  
pn aSOyR  
public class TestMethod { /9@ VnM  
@A8@j%CK1  
j4]y(AA  
public TestMethod() Q;eY]l8  
{ ///xx/weblogic60b2_win.exe "|d# +C  
try{ p2(Z(V7*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %v<BE tq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y3@5~4+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _ v3VUm#  
fileFetch.start(); Hus.Jfam  
} ;^|:*  
catch(Exception e){e.printStackTrace ();} /zIUYY  
OCbwV7q:  
}6 Mo C0  
} #-bz$w#*  
|aS272'  
G57c 8}\4  
public static void main(String[] args) h~u|v[@{J  
{ vW`[CEm^X  
new TestMethod(); +E }q0GV  
} $3^Cp_p6  
} MW|:'D`  
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