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http断点续传简单实现(java)

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/* t$g@+1p4  
**SiteFileFetch.java x4-_K%  
*/ ~Aw.=Yi=  
package NetFox; OZ, Xu&N  
import java.io.*; AA<QI'6  
import java.net.*; JasA w7  
]-cSTtO  
DIF-%X5  
public class SiteFileFetch extends Thread { +0g L!r  
tR(nD UHV5  
~Xz?H=}U+  
SiteInfoBean siteInfoBean = null; //文件信息Bean p((a(Q/  
long[] nStartPos; //开始位置 -_ <z_IL\%  
long[] nEndPos; //结束位置 4/AE;y X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 OxqkpK&  
long nFileLength; //文件长度 SVBo0wvz-  
boolean bFirst = true; //是否第一次取文件 }56WAP}Z 4  
boolean bStop = false; //停止标志 >)+N$EN  
File tmpFile; //文件下载的临时信息 58P[EMhL  
DataOutputStream output; //输出到文件的输出流 il% u)NN  
|H.ARLS  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) d r$E:kr  
public SiteFileFetch(SiteInfoBean bean) throws IOException o>\o=%D.a  
{ OXI>`$we  
siteInfoBean = bean; ;b!qt-;.<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); pv]" 2'aQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SM\qd4  
if(tmpFile.exists ()) i>e?$H,/  
{ Vh N6 oI  
bFirst = false; EO%"[k  
read_nPos(); GA;h7  
} ><I{R|bC  
else 1Eb2X}XC  
{ @Gt.J*!s/  
nStartPos = new long[bean.getNSplitter()]; psUT2  
nEndPos = new long[bean.getNSplitter()]; \,pObWm  
} jl5&T{z  
fZrh_^yH  
LGK@taw^  
Kc, i$FH  
} bEln.)  
d/!\iLF  
mM:%-I\$   
public void run() me@)kQ8M  
{ sou~m,#  
//获得文件长度 Jj?HOtaM  
//分割文件 :W;eW%Y  
//实例FileSplitterFetch ;Y0M]pC  
//启动FileSplitterFetch线程 ~r~YR=  
//等待子线程返回 iBI->xU[U  
try{ Cz &3=),G  
if(bFirst) ~d\^ynQ  
{ t YxN^VqU  
nFileLength = getFileSize(); O_]hbXV0  
if(nFileLength == -1) n'0r (  
{ .f"1(J8  
System.err.println("File Length is not known!"); [S1 b\f#  
} \*[DR R0  
else if(nFileLength == -2) huW,kk<]y  
{ `jSegG'  
System.err.println("File is not access!"); p6V#!5Q  
} ~6IY4']m*  
else ;wkMa;%`g|  
{ ka6E s~  
for(int i=0;i<nStartPos.length;i++) %-a;HGbZn  
{ `mA;1S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]6M,s0  
} @yo6w}3+-  
for(int i=0;i<nEndPos.length-1;i++) @<`V q  
{ rVP{ ^Jdo  
nEndPos = nStartPos[i+1]; Qj|rNeM_  
} 3!$+N\ #w  
nEndPos[nEndPos.length-1] = nFileLength; =fJU+N+<  
} &,yF{9$G  
} h3-^RE5\`S  
-+Ot' ^  
OF03]2j7<|  
//启动子线程 }xBDyr63  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bN7m[GRO.  
for(int i=0;i<nStartPos.length;i++) A*~G[KC3(  
{ (Gw*x sn1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TgaxZW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .$7RF!p  
nStartPos,nEndPos,i); K_~kL0=4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a"X h  
fileSplitterFetch.start(); r-go921  
} CAC%lp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `+rwx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5:jme$BI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Arm'0)B>  
nEndPos = " + nFileLength); kJpO0k9?eY  
// fileSplitterFetch[nPos.length-1].start(); TY'c'u,  
[T,Hpt  
(xHu@l!]  
//等待子线程结束 i1XRB C9  
//int count = 0; AO>b\,0Me  
//是否结束while循环 U[02$gd0l  
boolean breakWhile = false; DxwR&S{  
1ANFhl(l  
}dpTR9j=  
while(!bStop) !y B4;f$  
{ K4jHha  
write_nPos(); &a=78Z  
Utility.sleep(500); 1G7l+6w5~^  
breakWhile = true; "[!b5f3!I  
' tY(&&  
+<.o,3  
for(int i=0;i<nStartPos.length;i++) EQ ee5}  
{ qB (Pqv  
if(!fileSplitterFetch.bDownOver) #>("(euXMF  
{ LWm1j:0  
breakWhile = false; bm 4RRI  
break; Y!_{:2H8p  
} IdN3Ea]  
} / Ws>;0  
if(breakWhile) mvK^')  
break; y: x<`E=  
Ak,JPz T  
a#"orc j  
//count++; '~Cn+xf4]  
//if(count>4) rR :ZTfJs"  
// siteStop(); tT>LOI_z  
} Jw8?o/1D@  
}x\#ul)  
`-.2Z 0  
System.err.println("文件下载结束!"); pB\:.?.pd  
} r dSL  
catch(Exception e){e.printStackTrace ();} 8-NycG&)  
} ~abyjM  
X!K>.r_Dg  
`(h^z>%  
//获得文件长度 bsDA&~)s  
public long getFileSize() ;b*qunJ3L  
{ fs 2MYat  
int nFileLength = -1; l=p_  
try{ 5{k,/Z[L  
URL url = new URL(siteInfoBean.getSSiteURL()); iuGwc086  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x<M::")5!V  
httpConnection.setRequestProperty("User-Agent","NetFox"); wpuK?fP  
aqN{@|  
\OtreYi  
int responseCode=httpConnection.getResponseCode(); bf0,3~G,P  
if(responseCode>=400) o+&Om~W  
{ T>'O[=UWh  
processErrorCode(responseCode); ,wes*  
return -2; //-2 represent access is error #55:qc>m  
} <O 0Q]`i  
Rlk3AWl2u  
V%s7*`U  
String sHeader; )f|`mM4DW!  
j!>P7 8  
OyVP_Yx,V  
for(int i=1;;i++) Q;8z&4s@  
{ $uDgBZA\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Qgj# k  
//Utility.log(in.readLine()); 6vsA8u(|V#  
sHeader=httpConnection.getHeaderFieldKey(i); eZAMV/]jH  
if(sHeader!=null) #| _VN %!  
{ 'Og@<~/Xy  
if(sHeader.equals("Content-Length")) ?&#LmeZ}K  
{ Bh2l3J4X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p"p~Bx  
break; [oV M9 Q  
} &L$9Ii  
} ZI!:  
else >-I <`y-H  
break; 4T(d9y  
} IS&qFi}W|W  
} 63Zu5b"O/  
catch(IOException e){e.printStackTrace ();} @!fUp b  
catch(Exception e){e.printStackTrace ();} &]o-ZZX  
XQ}J4J~Vm  
8C@u+tx  
Utility.log(nFileLength); / S]RP>cQ  
W+!UVUpW  
AE}cHBwZE  
return nFileLength; o'$"MC+  
} ]6^<VC`5D  
g= $U&Hgs  
8xO   
//保存下载信息(文件指针位置) !2KQi=Ng  
private void write_nPos() ~dr,;NhOLJ  
{ o@zxzZWg  
try{ :TU|:2+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZQE1]ht  
output.writeInt(nStartPos.length); z qq  
for(int i=0;i<nStartPos.length;i++) VQHB}Y@^  
{ \uOM,98xS  
// output.writeLong(nPos); '_G\_h}5  
output.writeLong(fileSplitterFetch.nStartPos); Ah wi  
output.writeLong(fileSplitterFetch.nEndPos); sWo`dZ\6WB  
} \s&Mz;:  
output.close(); -p_5T*R  
} d=xjLbsZ  
catch(IOException e){e.printStackTrace ();} _J!^iJ  
catch(Exception e){e.printStackTrace ();} h5'hP>b#  
} &|Duc} t  
?"9h-g3`x}  
Lmte ~oBi  
//读取保存的下载信息(文件指针位置) mp8GHV  
private void read_nPos() 88osWo6rG  
{ 60!%^O =  
try{ _eiqs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6/8K2_UeoW  
int nCount = input.readInt(); (NvjX})eh  
nStartPos = new long[nCount]; PK2;Ywk`  
nEndPos = new long[nCount]; v;<gCzqQh  
for(int i=0;i<nStartPos.length;i++) 5U~KYy^v  
{ JPqd} :u3  
nStartPos = input.readLong(); %, psUOY  
nEndPos = input.readLong(); +-@n}xb@  
} |&=-Nm  
input.close(); <l5i%?  
} =tP9n;D  
catch(IOException e){e.printStackTrace ();} FYYc+6n  
catch(Exception e){e.printStackTrace ();} T%eBgseS  
} }:IIk-JoC  
fwz:k]vk  
}N[X<9^ Z  
private void processErrorCode(int nErrorCode) zkRAul32|  
{ U9:)qvMXe  
System.err.println("Error Code : " + nErrorCode); t`H1]`c?  
} _U^[h!  
~9+01UU^  
d^}p#7mB\  
//停止文件下载 H]/ ~ #a  
public void siteStop() " !EnQB=  
{ M_ukG~/  
bStop = true; K'ZNIRr/ C  
for(int i=0;i<nStartPos.length;i++) !vgY3S0?rq  
fileSplitterFetch.splitterStop(); LIcc0w3  
[LnPV2@e  
fmz"Zg 9=  
} 3@V?L:J  
} <==uK>pET  
//负责部分文件的抓取 :'DyZy2Fd  
**FileSplitterFetch.java l/G +Xj4M  
*/ dxs5woP  
package NetFox; lr>NG,N  
[ey# ,&T  
Q ]CMm2L^f  
import java.io.*; @njNP^'Kx  
import java.net.*; "u^Erj# /  
'v]0;~\mp>  
$NVVurXa  
public class FileSplitterFetch extends Thread { AZ3T#f![L@  
.|O T#"LP  
MIZdk'.U  
String sURL; //File URL |_TiF ;^  
long nStartPos; //File Snippet Start Position > ubq{'  
long nEndPos; //File Snippet End Position 7\ _MA!:<  
int nThreadID; //Thread's ID q%4X1 W  
boolean bDownOver = false; //Downing is over S oeoUI]m  
boolean bStop = false; //Stop identical i&:SWH=  
FileAccessI fileAccessI = null; //File Access interface x []ad"R  
@ 8H$   
Fe0M2%e;|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *-9i<@|(U^  
{ OvX&5Q5  
this.sURL = sURL; {nKw<F2  
this.nStartPos = nStart; ' 4FH9J  
this.nEndPos = nEnd; z}MxMx c4h  
nThreadID = id; M1/d7d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KHAc!4lA  
} \AwkK3  
"A}sD7xy9  
6'^E ],:b  
public void run() ;TJpD0  
{ L(;$(k-/(  
while(nStartPos < nEndPos && !bStop) O{l4 f:51  
{ zTa5 N  
So&gDR;b  
/"Vd( K2Z  
try{ r%=-maPL[  
URL url = new URL(sURL); B"_O!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b-<0\@`Z#  
httpConnection.setRequestProperty("User-Agent","NetFox"); v?VDASR2`  
String sProperty = "bytes="+nStartPos+"-"; >Q/;0>V  
httpConnection.setRequestProperty("RANGE",sProperty); V$ H(a`!  
Utility.log(sProperty); h <4`|Bg+  
/i,n75/y?  
Lu}jk W*  
InputStream input = httpConnection.getInputStream(); "QnYT3[l"  
//logResponseHead(httpConnection); c~vhkRA  
\n[kzi7  
VCWW(Y1Fd  
byte[] b = new byte[1024]; I<#X#_YP  
int nRead; $+Ze"E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Lk !)G'42  
{ ov_l)vt  
nStartPos += fileAccessI.write(b,0,nRead); +aOdaNcI  
//if(nThreadID == 1) I}_}VSG(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BY~Tc5  
} vIRT$W' O}  
r:bJU1P1$s  
qofAA!3z  
Utility.log("Thread " + nThreadID + " is over!"); EHC7b^|3}  
bDownOver = true; 6B?jc/V.R  
//nPos = fileAccessI.write (b,0,nRead); N9!L8BBaK  
} #yH+ENp0   
catch(Exception e){e.printStackTrace ();} =de'Yy:\-  
} ]6e(-v!U  
} Jc#D4e1#  
i.t%a{gL  
G!6b )4L-  
//打印回应的头信息 &[[r|  
public void logResponseHead(HttpURLConnection con) Nm"P8/-09  
{ NBPP?\1  
for(int i=1;;i++) >/A]C$?3  
{ hoq2zDjD  
String header=con.getHeaderFieldKey(i); c& ;@i$X(  
if(header!=null) ~q3O,bb{   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OyO]; Yk  
Utility.log(header+" : "+con.getHeaderField(header)); Rn?JMM]  
else FaeKDbLJr  
break; 9vV==A#  
} 3&y-xZu]  
} / dJz?0  
hVF^ "$  
:IZAdlz[@  
public void splitterStop() yh E%X  
{ +VkL?J  
bStop = true; 8._uwA<[  
} IAQ<|3Q  
(F&LN!Hn>p  
EIRDH'[L  
} zP44 Xhz  
G%I .u  
dx@dnWRT,  
/* G!Brt&_'  
**FileAccess.java 3Q$ 4`p;  
*//文件访问(定位,写) ;5ki$)v"  
package NetFox; =Ydrct  
import java.io.*; >=0]7k;  
T_D3WHp  
%>&ex0j]  
public class FileAccessI implements Serializable{ k ;^$Pd?t  
z6R|1L 1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p-i Fe\+  
RandomAccessFile oSavedFile; _{jC?rzb  
long nPos; Z^>4qf,k  
D3 C7f'  
fQ5v?(  
public FileAccessI() throws IOException C][$0  
{ fB+h( 2N~  
this("",0); -~]H5er`  
} Mc,|C)  
O.+J%],  
y$%oR6 K7-  
public FileAccessI(String sName,long nPos) throws IOException 7Y8~ ")f  
{ <YW)8J  
oSavedFile = new RandomAccessFile(sName,"rw"); Z{B  e  
this.nPos = nPos; W4o8]&A  
oSavedFile.seek(nPos); r.e K;  
} dcY(1p)  
RHFRN&RU$  
H0s*Lb  
public synchronized int write(byte[] b,int nStart,int nLen) %'1iT!g8  
{ cTq@"v di  
int n = -1; 4G,FJjE`p  
try{  2 q4p-  
oSavedFile.write(b,nStart,nLen); 9K@ I  
n = nLen; &\ 9%;k  
} f- XUto  
catch(IOException e) &<;T$Y  
{ vqN/crJ@  
e.printStackTrace (); r,JQR)l0@V  
} /Z6lnm7wJ  
[_JdV(]$  
vi}16V84l  
return n; Ca'BE#q  
} Ro]Z9C>1o  
`-{l$Hn9|~  
*,z/q6  
} s>/Xb2\  
{g.YGO  
YIRe__7-NU  
/* + Tp% *  
**SiteInfoBean.java lMFo)4&P  
*/ K? o p3}f?  
package NetFox; |aP`hVm  
S=,czs3N  
l6bY!I>  
public class SiteInfoBean { EsKgS\`RZ  
hV(^Y)f  
Z;G*wM"  
private String sSiteURL; //Site's URL F- -g?Q^  
private String sFilePath; //Saved File's Path D>y5&`  
private String sFileName; //Saved File's Name &)OI!^ (  
private int nSplitter; //Count of Splited Downloading File Zye04&x9k  
"Ol:ni1  
zwV!6xG  
public SiteInfoBean() \ UrD%;sq  
{//nSplitter的缺省值为5 08xo_Oysq  
//default value of nSplitter is 5 X:UlL"G  
this("","","",5); KdkL_GSLT  
} |yk/iO(  
)pl5nu#<  
y7>3hfn~w  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S'!&,Dxq^  
{ |~5cN m  
sSiteURL= sURL; TBt5Nqks-  
sFilePath = sPath; GM2}]9  
sFileName = sName; { YQS fk  
this.nSplitter = nSpiltter; r2SZC`Z}-M  
{Phq39g  
R Th=x.  
} O8 .iP+  
v's1 &%sM  
d'96$e o~  
public String getSSiteURL() /''=V.-N  
{ f!kZyD7  
return sSiteURL; uZL]mwkj]  
} 4m< ]qw  
 skl3/!  
6m$X7;x}  
public void setSSiteURL(String value) =;-C;gn:w  
{ =Smd/'`_  
sSiteURL = value; {j$2=0Cec  
} i975)_X(  
4"@;.C""  
?7NSp2aq2A  
public String getSFilePath() UK,bfLPt~  
{ .L^*9Y0)  
return sFilePath; WkiT,(i  
} 6agq^wI  
6#Z] yk+p  
/}6I3n  
public void setSFilePath(String value) B/l^=u+-  
{ +\Vw:~e  
sFilePath = value; ~+1mH  
} KfjWZ4{v  
_+48(Q F<  
?+EAp"{j  
public String getSFileName() UWO3sZpU  
{ /V*SI!C<f  
return sFileName; F% n}vA`  
} (W h)Ov"  
{Lal5E4-  
Q &W>h/  
public void setSFileName(String value) 1\( N,'h  
{ [TA.|7&  
sFileName = value; /!0&b?  
} `T*Y1@FV  
 x(HHy,  
-ZE YzZqY  
public int getNSplitter() </;e$fh`  
{ .hH_1Mo8  
return nSplitter; l1T`[2  
} Z$J-4KN  
4}DFCF%B  
)K?7(H/j  
public void setNSplitter(int nCount) 02Vfg42  
{ a2.6 S./  
nSplitter = nCount; xwo *kFg  
} [KR%8[e  
} ^S`hKv&87  
2n3&uvf'TL  
f5F-h0HF`[  
/* bz>\n"'  
**Utility.java B0yJ9U= Fj  
*/ C5^WJx[  
package NetFox; q>(?Z#sB  
((`\i=-o5  
)&T 5 /+  
public class Utility { FDgo6x   
K9ia|2f  
m Z +dr[  
public Utility() v_Vw!u  
{ e'uC:O.u  
)w4U]inJ$"  
HlX~a:.7  
} ?ja%*0 R  
o*A, 6y  
//线程睡眠 U+'zz#0qN  
public static void sleep(int nSecond) 0&)6mO  
{ Njg87tKB  
try{ K/B$1+O  
Thread.sleep(nSecond); [_%u5sc-y  
} X~& 8^?  
catch(Exception e) $yi:0t8t  
{ G0!6rDu2,  
e.printStackTrace (); H_@6!R2  
} DNZ,rL:h  
} b4wT3  
}&+,y<>   
//日志 _*UI}JtlS  
public static void log(String sMsg) :q3w;B~  
{ 3:Nc`tM_  
System.err.println(sMsg); !2Ompcr1  
} 1\,k^Je7  
Gjeb)Y6N  
*~GI-h  
public static void log(int sMsg) :ILpf+`yY  
{ (hOD  
System.err.println(sMsg); Il4]1d|  
} MOh&1]2j5  
} ~x(|'`  
iLv -*%%  
:%9R&p:'ar  
/* P7W|e~]Yq  
**TestMethod.java ?,7!kTRH  
*/ d#+Ne f5  
package NetFox; o:v_I{  
!S&/Zp  
?@PSD\  
public class TestMethod { e46`"}r  
|pZ7k#%  
]8wm1_qV  
public TestMethod() rAtCG1Vr  
{ ///xx/weblogic60b2_win.exe j]&Qai~}Y  
try{ GU`q^q@Ea  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?i_/f}.K  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); } Ifa5Lq)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p>pN?53S  
fileFetch.start(); ' *XIp:  
} I}u\ov_Su  
catch(Exception e){e.printStackTrace ();} 0`.&U^dG  
|WS@q'  
i 1w ]j  
} evZP*N~G  
p#w8$Qjp  
u9Adu`  
public static void main(String[] args) B&B4 P  
{ h-Y>>l>PW0  
new TestMethod(); Tv'1IE  
} pHb,*C</  
} DjaXJ?'  
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