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http断点续传简单实现(java)

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/* \G &q[8F\  
**SiteFileFetch.java !fG`xZ~  
*/ V@1K  
package NetFox; >oc&hT  
import java.io.*; KXga {]G:  
import java.net.*; =?- s azF&  
jT q@@y  
Q##L|*Qy  
public class SiteFileFetch extends Thread { STQ~mFs"  
{_*$X  
ffE>%M*  
SiteInfoBean siteInfoBean = null; //文件信息Bean JQWW's}  
long[] nStartPos; //开始位置 v D4<G{  
long[] nEndPos; //结束位置 d9uT*5f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8\ WOss)al  
long nFileLength; //文件长度 Ol. rjz9  
boolean bFirst = true; //是否第一次取文件 de?lO ;8  
boolean bStop = false; //停止标志 e.^Y4(  
File tmpFile; //文件下载的临时信息 DM@&=c  
DataOutputStream output; //输出到文件的输出流 QCk(qlN'h9  
Z8_Q Kw>  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) x<e-%HB*-  
public SiteFileFetch(SiteInfoBean bean) throws IOException IpMZ{kJlv`  
{ _79 ?,U]  
siteInfoBean = bean; Y=N; Bj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #o-CG PE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ) _O 6_  
if(tmpFile.exists ()) qfzT8-Y  
{ db.E-@W.OI  
bFirst = false; s|=.L&"   
read_nPos(); * E3 c--  
} K=C).5=U  
else ]&/KAk  
{ 1)f~OL8o  
nStartPos = new long[bean.getNSplitter()]; y[@<goT  
nEndPos = new long[bean.getNSplitter()]; }8qsE  
} GCEq3 ^/  
#T8$NZA  
= g)G!  
5&*B2ZBzH  
} Nd4!:.  
)<1}`9G  
1z[GYRSt  
public void run() y:+s*x6Vg  
{ %?WmWs0  
//获得文件长度 -'!%\E;5  
//分割文件 U1^R+ *yp  
//实例FileSplitterFetch tcxs%yWO1  
//启动FileSplitterFetch线程 S4Vv _k-&  
//等待子线程返回 ku}I; k |  
try{ l6Q75i)eF  
if(bFirst) NTtRz(   
{ :+>:>$ao  
nFileLength = getFileSize(); S*1Km&  
if(nFileLength == -1) 2x*C1   
{ MO$ dim>  
System.err.println("File Length is not known!"); s GP}>w-JZ  
} 1y5$  
else if(nFileLength == -2) h}_1cev?  
{ B:\TvWbu  
System.err.println("File is not access!"); /8` S}g+  
} |<ZkJR3B  
else grhwPnKl  
{ ;|LS$O1c  
for(int i=0;i<nStartPos.length;i++) $yx34=  
{ ,\K1cW~U5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /U%Xs}A)  
} S qQqG3F  
for(int i=0;i<nEndPos.length-1;i++) =Gq 'sy:h  
{ k(;c<Z{?1  
nEndPos = nStartPos[i+1]; _8'FI_E3  
} P2Ja*!K]  
nEndPos[nEndPos.length-1] = nFileLength; vK\;CSk  
} y[l19eU  
} RZ[r XV5  
cKX6pG  
1Bz'$u;  
//启动子线程 ,{{uRs/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; F W# S.<  
for(int i=0;i<nStartPos.length;i++) :oH"  
{ Z<#beT6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .#b!#   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $bU|'}QR  
nStartPos,nEndPos,i); x6ig,N~AO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \8!&X cA  
fileSplitterFetch.start(); .#;;pu7W  
} fodr1M4J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?7cF_Zvve  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M9@#W"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }>:x  
nEndPos = " + nFileLength); nD+vMG1~w  
// fileSplitterFetch[nPos.length-1].start(); uv2!][  
I^{PnrB  
U!-|.N,  
//等待子线程结束 7 '@l?u/6  
//int count = 0; 1lNg} !)[K  
//是否结束while循环 9 0[gXj  
boolean breakWhile = false; e.0vh?{\  
B*owV%  
y\Z-x  
while(!bStop) 8fdK|l w  
{ F~ n}Ep~1  
write_nPos(); }q(IKH\&  
Utility.sleep(500); AX%9k  
breakWhile = true; OX ?9 3AlG  
>29eu^~nh  
qx"?')+  
for(int i=0;i<nStartPos.length;i++) -9U'yL90B  
{ 9b !+kJD  
if(!fileSplitterFetch.bDownOver) {cv,Tz[Q>  
{ [j5 ^Zb&0  
breakWhile = false; V&_5q`L  
break; %xR;8IO  
} 2WIbu-"l  
} `\&qk)ZP  
if(breakWhile) 9`)NFy?  
break; w<awCp  
N2}].}  
R9yK"  
//count++; O;:8mm%(  
//if(count>4) ^AD/N|X^  
// siteStop(); C/[2?[  
} OZ_'& CZ  
~R)Km`t  
"$#x+|PyC  
System.err.println("文件下载结束!"); 'W$jHs  
} AdB5D_ Ir  
catch(Exception e){e.printStackTrace ();} .l*]W!L]  
} *kxk@(lT?  
6yF4%Sz9  
B{|P}fN5}  
//获得文件长度 =?57*=]0M  
public long getFileSize() _-Aw`<_*-  
{ fZXJPy;n  
int nFileLength = -1; ?/{ qRz'C<  
try{ xGqe )M>8?  
URL url = new URL(siteInfoBean.getSSiteURL()); a'Qy]P}'Ug  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LIVVb"V|,  
httpConnection.setRequestProperty("User-Agent","NetFox"); /PIU@$DV  
>.#uoW4ZV  
JPiC/  
int responseCode=httpConnection.getResponseCode(); k-T_,1l{  
if(responseCode>=400) \nx ^=4*yk  
{ / v;g v[  
processErrorCode(responseCode); C did*hxJ  
return -2; //-2 represent access is error -b(:kAwStk  
} [/*85 4  
"aP>}5<h  
E+"INX7  
String sHeader; sj`9O-?49  
(>>pla^  
T_,LK7D  
for(int i=1;;i++) A A<9 XC  
{ "F|OJ@ M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -NZj :N  
//Utility.log(in.readLine()); }<&g1x'pa  
sHeader=httpConnection.getHeaderFieldKey(i); Qkk~{OuC  
if(sHeader!=null) :H\6wJ  
{ _?@>S7-  
if(sHeader.equals("Content-Length")) &.o}(e:]  
{ {TdK S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6yTL7@V|B  
break; _>A])B ^  
} }k<b)I*A  
} A@_F ;4X  
else "`,PLC  
break; E] t:_v  
} J(M0t~RZ  
} rg_-gZl8&z  
catch(IOException e){e.printStackTrace ();} f8N  
catch(Exception e){e.printStackTrace ();} _ZD)#?  
+B_q? 6pR  
c.,:r X0S  
Utility.log(nFileLength); rQ*'2Zf'<  
ui70|  
P}&7G-  
return nFileLength; 0} liK  
} ?GD{}f33  
ozkN&0  
 h:#  
//保存下载信息(文件指针位置) .rG Rdb  
private void write_nPos() ERGDo=j  
{ v[r:1T@  
try{ 0V}vVAa(B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @w6^*Z_hQ  
output.writeInt(nStartPos.length); HC4ad0Gs+{  
for(int i=0;i<nStartPos.length;i++) >}u?{_s *0  
{ (LRv c!`"  
// output.writeLong(nPos); jfqWcX.X=  
output.writeLong(fileSplitterFetch.nStartPos); XT~JP  
output.writeLong(fileSplitterFetch.nEndPos); * 2T&pX  
} C+ r--"Z  
output.close(); :'Imz   
} Fdu0?H2TL  
catch(IOException e){e.printStackTrace ();} J%f5NSSU{6  
catch(Exception e){e.printStackTrace ();} ?8! 4!P%n  
} '/;#{("  
-1S+fUkiK/  
;-^WUf |  
//读取保存的下载信息(文件指针位置) %'4dg k  
private void read_nPos() in#qV  
{ na  $z\C\  
try{ YV{^S6M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p5)A"p8"9,  
int nCount = input.readInt(); y @Y@"y  
nStartPos = new long[nCount]; s.C-II?e  
nEndPos = new long[nCount]; !S%XIq}FX  
for(int i=0;i<nStartPos.length;i++) yql+N[  
{ og. dYs7W4  
nStartPos = input.readLong(); Zf]d'oW{/  
nEndPos = input.readLong(); A+Y>1-=JO  
} Lkk'y})/  
input.close(); Ao`9fI#q  
} ;n7k_K#0z!  
catch(IOException e){e.printStackTrace ();} F2oY_mA  
catch(Exception e){e.printStackTrace ();} 'D\(p,(Mt  
} -Q 6W`*8  
:;{U2q+  
qdZn9i  
private void processErrorCode(int nErrorCode) X"iy.@7  
{ E;VW6[M  
System.err.println("Error Code : " + nErrorCode); N<Y-]xS  
} \)y5~te*  
a_QO)  
w|?Nq?KA  
//停止文件下载 NqhRJa63  
public void siteStop() >4~{ CXZ  
{ Xd|@w{.m*  
bStop = true; aKH\8O4L5  
for(int i=0;i<nStartPos.length;i++)  A{5 k}  
fileSplitterFetch.splitterStop(); Ha)w*1&w"  
kX[I|Z=  
/kx:BoV  
} HEjV7g0E  
} D\j1`  
//负责部分文件的抓取 dHf_&X2A  
**FileSplitterFetch.java rS(693kb  
*/ nF A7@hsm  
package NetFox; _~Lhc'^p*  
s}`=pk/FM  
OX|/yw8  
import java.io.*; Eto0>YyZ  
import java.net.*; u4z]6?,"e  
uZmfvMr3  
w{2V7*+l  
public class FileSplitterFetch extends Thread { :Nc~rOC _  
",&}vfD4M  
1/a*8vuGh  
String sURL; //File URL YDjQ&EH  
long nStartPos; //File Snippet Start Position _k5KJKvr  
long nEndPos; //File Snippet End Position vuDp_p*]S  
int nThreadID; //Thread's ID ! ~&X1,l1*  
boolean bDownOver = false; //Downing is over gA~Ih  
boolean bStop = false; //Stop identical oPzt1Y  
FileAccessI fileAccessI = null; //File Access interface BR5$;-7W  
wg!  
0Lc X7gU>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kz,Nz09}W  
{ Ms^Y:,;Hi  
this.sURL = sURL; .o|Gk 5)  
this.nStartPos = nStart; Uy_`=JZ  
this.nEndPos = nEnd; |P5?0{  
nThreadID = id; r^*,eF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {_^sR}%]F  
} hs<7(+a  
n2(~r 'r)  
Fo?2nQ<  
public void run() [uAfE3  
{ /:yKa=$  
while(nStartPos < nEndPos && !bStop) =\:YNP/  
{ <ezvz..g  
2!]':(8mR  
1|z>} xP  
try{ ut-UTW  
URL url = new URL(sURL); J"6_H =s   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =x/]2+ s  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q*mPU=<  
String sProperty = "bytes="+nStartPos+"-"; [R A=M  
httpConnection.setRequestProperty("RANGE",sProperty); !i)?j@D  
Utility.log(sProperty); 3.R?=npA  
NwT3e&u%|  
@*%5"~F  
InputStream input = httpConnection.getInputStream(); @zd)]O]xH?  
//logResponseHead(httpConnection); dBobVT'  
?1OS%RBF  
)2bPu[U  
byte[] b = new byte[1024]; '7xmj:.==  
int nRead; A`X$jpAn&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h"wXmAf4%  
{ Eg  w?  
nStartPos += fileAccessI.write(b,0,nRead); 3ufUB^@4v  
//if(nThreadID == 1) bE]2:~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M5 Pvc  
} uERc\TZ  
]dk~C?H  
lW^RwNcd  
Utility.log("Thread " + nThreadID + " is over!"); _5.7HEw>/  
bDownOver = true; 1S.nqOfx  
//nPos = fileAccessI.write (b,0,nRead); $stJ+uh  
} (q:L_zFj>"  
catch(Exception e){e.printStackTrace ();} mI"|^!L  
} 6"jq/Pu  
} 42# rhgW  
!30Dice  
uiDR}   
//打印回应的头信息 47 m:z5;  
public void logResponseHead(HttpURLConnection con) Eer rIV  
{ -f Zm_FE  
for(int i=1;;i++) q ,}W.  
{ v>7=T 8  
String header=con.getHeaderFieldKey(i); EVRg/ {X  
if(header!=null) kCN9`9XI{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7z F29gC  
Utility.log(header+" : "+con.getHeaderField(header)); 1[X+6viE  
else bS* "C,b~s  
break; K[T? --H  
} zbi[r  
} Du[$6  
->K*r\T  
4V<s"  
public void splitterStop() |3"'>* J  
{ BhdJ/C^  
bStop = true; FeSe^^dW  
} a8Ci 7<V  
oqUtW3y  
q| gG{9  
} u4#BD!W  
WI}P(!h\J  
w(.k6:e  
/* c5]^jUB6  
**FileAccess.java XQlK}AK  
*//文件访问(定位,写) aSKI %<?xN  
package NetFox; 0[9A*  
import java.io.*; ":eHR}Hzx  
oryoGy=(yk  
` [@ F3x  
public class FileAccessI implements Serializable{ MH!'g7iK8  
QXgh[9w G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,Qj7wFZ  
RandomAccessFile oSavedFile; !:rQ@PSy9  
long nPos; "{L%5:H@  
AP/5, M<  
Ngh9+b6[  
public FileAccessI() throws IOException Wd&!##3$Q  
{ Ojie.+'SB  
this("",0); ]}KmT"vA  
} l_+s$c  
[y=k}W}z  
.w[]Q;K_[)  
public FileAccessI(String sName,long nPos) throws IOException hD # Yz<  
{ r-&4<=C/N  
oSavedFile = new RandomAccessFile(sName,"rw"); H%Q@DW8~@  
this.nPos = nPos; F/&Z1G.  
oSavedFile.seek(nPos); ",`fGu )  
} y\r8_rBo  
x1Z?x,-D"  
wdl6dLu  
public synchronized int write(byte[] b,int nStart,int nLen) 7 P=1+2V  
{ 2-]gHAw%  
int n = -1; ihf5`mk/$  
try{ 0=L:8&m  
oSavedFile.write(b,nStart,nLen); l"b78n  
n = nLen; IqcPml{\  
} .CrahV1G  
catch(IOException e) :m^eNS6:  
{ C!RxMccTh  
e.printStackTrace (); GwW!Q|tVz=  
} im4V6 f;%  
&7|=8Z[o  
sT'wps2  
return n; 1&Nk  
} Vk@u|6U'  
ryN/sjQC  
u|O5ZV-cd  
} 2+ >.Z.pX  
4N*Fq!k~  
l|U=(aA]h  
/* .5KRi6  
**SiteInfoBean.java osPX%k!yw  
*/ Xk(c2s&  
package NetFox;  V:F)m!   
IWuR=I$t  
&hyr""NkAm  
public class SiteInfoBean { Y -o*d@  
m:II<tv  
5JIa?i>B  
private String sSiteURL; //Site's URL pbR84g^p.S  
private String sFilePath; //Saved File's Path K=+w,H# `C  
private String sFileName; //Saved File's Name GkaIqBS  
private int nSplitter; //Count of Splited Downloading File 2O`uzT$  
SYeCz(H>d  
{$oZR" MP  
public SiteInfoBean() (9fqUbG  
{//nSplitter的缺省值为5 V5qvH"^  
//default value of nSplitter is 5 +%$!sp?  
this("","","",5); m"X0Owx  
} :}o0Eb  
)?I1*(1{A  
a?M<r>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o^d(mJZ.F~  
{ }g5h"N\$o  
sSiteURL= sURL; o24` 5Jdh  
sFilePath = sPath; X.%Xi'H  
sFileName = sName; y3c]zDjV  
this.nSplitter = nSpiltter; .oN<c]iqE  
.kBi" p&  
W446;)?5  
} @,pO%,E6  
l4|bpR Cp  
b ]1SuL  
public String getSSiteURL() _I3j 7f,V  
{ 9\R:J"X  
return sSiteURL; 2AzF@Pi^z  
} O&E1(M|*>  
FFK79e/5  
9k&lq$  
public void setSSiteURL(String value) r-H~MisL  
{ E6y/,s^~S_  
sSiteURL = value; gB71~A{J  
} Xe:B*  
6V*@ {  
4US8B=jk  
public String getSFilePath() V0c*M>V  
{ k2,n:7  
return sFilePath; V.: a6>]  
} = 14'R4:  
]J5[ZVz  
U$ _?T-x  
public void setSFilePath(String value) {~[H"h537t  
{ KFCuv15w,3  
sFilePath = value; "|.>pD#0&  
} f|w+}z  
.A&Ey5  
[ C] =p  
public String getSFileName()  Pb+oV  
{ xXp\U'Ad~~  
return sFileName; * j:  
}  &5O  
hy3[MOD$G  
T5Sa9\`>  
public void setSFileName(String value) [/6$P[  
{ eP(%+[g  
sFileName = value; lVARe3#  
} 2:&8FdU  
i8Yl1nF  
7==Uz?}C  
public int getNSplitter() N@58R9P<p  
{ `IFt;Ja\6  
return nSplitter; v}+axu/?  
} #fzvK+  
rRYP~ $c  
(GMKIw2  
public void setNSplitter(int nCount) G0^23j  
{ Y^2`)':  
nSplitter = nCount; {!o-y=  
} Qh? E* 9  
} hG2btmBht  
|\XjA4j  
Q`,D#V${D  
/* DN&ZRA  
**Utility.java 7iLm_#M  
*/ gt';_  
package NetFox; U@ALo  
}rn}r4_a  
Kbg`ZO*  
public class Utility { y@nWa\i G  
w4:n(.;HK  
[I4K`>|Z  
public Utility() 4)]g=-3  
{ Olj]A]v}  
n&r-  
e\%QHoi>u  
} (=QaAn,,R  
7 I&7YhFI  
//线程睡眠 {QM;%f  
public static void sleep(int nSecond) DcQ^V4_  
{ oZA|IF8U0  
try{ A0V"5syY  
Thread.sleep(nSecond); _B 8e 1an  
} 2 t< dCw  
catch(Exception e) f"k?Ix\ e  
{ lqF{Y<l  
e.printStackTrace (); o~NeS|a  
} 7B"J x^  
} 0`h[|FYV  
KQJn\#>  
//日志 Jk}L+X vv  
public static void log(String sMsg) P qagep d  
{ 69dFd!G\  
System.err.println(sMsg); [{}9"zB$x0  
} E,c~.jYc  
f8#WT$Ewy  
-E2[PW4$  
public static void log(int sMsg) J.$<Lnt>u  
{ 7. G   
System.err.println(sMsg); Ua5m2&U1  
} /JEH%)  
} (|' w$  
xp)#a_}  
_-%ay  
/* lE?e1mz{  
**TestMethod.java JjfNH ~  
*/ yD#w @yG  
package NetFox; { )'D<:T  
d#ya"e>  
!V+5$TsS  
public class TestMethod { F}H!vh[  
p$?c>lim  
IywovN Tr  
public TestMethod() y z9`1R2c  
{ ///xx/weblogic60b2_win.exe KfG%#2\G_  
try{ @Sq=#f/=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7@fd[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \#LKsQa  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >,@Fz)\:{'  
fileFetch.start(); <j ;HRm  
} nKu`Ta*fX  
catch(Exception e){e.printStackTrace ();} ,H22;UV9  
?9H7Twi+T  
**_VNDK+  
} |GdA0y\v*}  
iJ?8)}  
Q, #M 0  
public static void main(String[] args) 'x+0 yd  
{ Pu/0<Orp7  
new TestMethod(); }td+F&l($V  
} UM|GX  
} >B8)Wb :  
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