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http断点续传简单实现(java)

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/* Ai5D[ykX  
**SiteFileFetch.java RGLi#:0_.x  
*/ c 4L++ u#  
package NetFox; 01o,9_|FL  
import java.io.*; VRz9;=m  
import java.net.*; 4|KtsAVp{  
>('Z9<|r:  
eed!SmP  
public class SiteFileFetch extends Thread { $~:|Vj5iZ\  
d7v_>  
\Gy+y`   
SiteInfoBean siteInfoBean = null; //文件信息Bean 8#15*'Y  
long[] nStartPos; //开始位置 _E xd:  
long[] nEndPos; //结束位置 CI@qT}Y_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W.  p'T}2  
long nFileLength; //文件长度 o`\@Yq$.  
boolean bFirst = true; //是否第一次取文件 (?~*.g!  
boolean bStop = false; //停止标志 [2nPr^  
File tmpFile; //文件下载的临时信息 (J`EC  
DataOutputStream output; //输出到文件的输出流 Eo_; N c  
%o#|zaK  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) u$mp%d8  
public SiteFileFetch(SiteInfoBean bean) throws IOException *x&y24  
{ iFaC[(1@a  
siteInfoBean = bean; Z_[jah  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); TXK82qTdf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R5MY\^H/A  
if(tmpFile.exists ()) {&.?u1C.\  
{ A{a`%FAV  
bFirst = false; };]f 3  
read_nPos(); nh%Q";  
} Vc| uQ8Mi  
else H?j!f$sw  
{ XB\n4 |4  
nStartPos = new long[bean.getNSplitter()]; X1Y+ao1)  
nEndPos = new long[bean.getNSplitter()]; VseeU;q  
} 1TL~I-G&n  
VHTr;(]hk  
Ixv/xI  
IT\ x0b cv  
} Y(P <9 m:  
pn4~?Aua0/  
i{6wns?KMj  
public void run() 1U~yu&  
{ R%^AW2   
//获得文件长度 glP W9q,f  
//分割文件 Y!lc/[8  
//实例FileSplitterFetch xsSX~`  
//启动FileSplitterFetch线程 {-)*.l=  
//等待子线程返回 RaLc}F)9   
try{ wv_<be[?*  
if(bFirst) dLy-J1h\  
{ #Vh$u%q3  
nFileLength = getFileSize(); $|r p5D6  
if(nFileLength == -1) <Z8^.t)|  
{ }uk]1M2=  
System.err.println("File Length is not known!"); :Y2J7p[+  
} yaKw/vV  
else if(nFileLength == -2) Hnc<)_DF  
{ c9)5G+   
System.err.println("File is not access!"); OFcqouGE  
} \Yd 0oe82  
else ?br4 wl  
{ uV+.(sjH  
for(int i=0;i<nStartPos.length;i++) ,?zOJ,wl  
{ RTRi{p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7__?1n~{  
} qb1[-H  
for(int i=0;i<nEndPos.length-1;i++) *]RCfHo\=  
{ a #4 'X*  
nEndPos = nStartPos[i+1]; Seb J}P1x  
} 2%(RB4+  
nEndPos[nEndPos.length-1] = nFileLength; *oU-V#   
} Y]>Qu f.!  
} O)Mf/P'  
"/}cV5=Z  
J{bNx8.&  
//启动子线程 #Bgq]6G2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KK4"H]!.  
for(int i=0;i<nStartPos.length;i++) Kk_h&by?  
{ {r2fIj~V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8  }(ul  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aj)?P  
nStartPos,nEndPos,i); @CU~3Md*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,%%}d9  
fileSplitterFetch.start(); '4}c1F1T_  
} I~.d/!>Z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]J* y`jn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /)E'%/"A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xMAb=87_  
nEndPos = " + nFileLength); t=Um@;wh  
// fileSplitterFetch[nPos.length-1].start(); q=40  l  
 p3YF  
1_z6O!rx  
//等待子线程结束 SS/t8Y4W  
//int count = 0; .A2u7*h&  
//是否结束while循环 t@O4 !mFH  
boolean breakWhile = false; ~8 w(M  
$ZOKB9QccC  
}.R].4gT  
while(!bStop) `bF] O"  
{ :xP$iEA`G  
write_nPos(); 11Hf)]M   
Utility.sleep(500); tSvklI  
breakWhile = true; U.B=%S  
t|Ipxk.)  
p!~{<s]  
for(int i=0;i<nStartPos.length;i++) "=BO,see9  
{ Y4B< ]C4  
if(!fileSplitterFetch.bDownOver) J|BZ{T}d  
{ XN=Cq*3}  
breakWhile = false; KZxA\,Y'5  
break; hIr$^%  
} r 7mg>3  
} K{s% h0  
if(breakWhile) 2i@t;h2E  
break;  !&Z,ev  
U5z}i^8a  
{)vue0 vP  
//count++; Q$(0Nx<  
//if(count>4) n*oa J<o%  
// siteStop(); A' \jaB  
} <XHS@|  
"n3i (sZ  
;5.o;|w?!  
System.err.println("文件下载结束!"); 6!3Jr  
} I:qfB2tL)O  
catch(Exception e){e.printStackTrace ();} n6a*|rE  
} 426)H_wx  
8zRb)B+  
%ycCNS  
//获得文件长度 Z{w{bf1&A  
public long getFileSize() "k${5wk#Fl  
{ [?$|   
int nFileLength = -1; Gkr^uXNg#  
try{ ?"aj&,q+  
URL url = new URL(siteInfoBean.getSSiteURL()); iZy`5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L8~nx}UP5  
httpConnection.setRequestProperty("User-Agent","NetFox"); O&:0mpRZ  
VhAZncw  
w$5N6  
int responseCode=httpConnection.getResponseCode(); {xC CUU  
if(responseCode>=400) 'ZHu=UT7_  
{ WLAJqmC]  
processErrorCode(responseCode); >Ufjmm${  
return -2; //-2 represent access is error ; -RhI_  
} W].P(A>m  
,Dz2cR6  
x,Cc$C~YP  
String sHeader; l}DCK  
IKK<D'6  
K+` Vn  
for(int i=1;;i++) :);]E-ch  
{ NS l$5E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5g- apod  
//Utility.log(in.readLine()); vl@t4\@3  
sHeader=httpConnection.getHeaderFieldKey(i); 1 ]@}+H  
if(sHeader!=null) Zw5\{Z0  
{ %;0w2W  
if(sHeader.equals("Content-Length")) fxDY:l  
{ 3_atv'I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }eX_p6bBw  
break; X*~NE\  
} @Y>3-,o,S  
} +fhyw{  
else |7Q8WjCQ{m  
break; R0<ka[+  
} n;"4`6L~  
} z#!xqIg0  
catch(IOException e){e.printStackTrace ();} 7[-jr;v  
catch(Exception e){e.printStackTrace ();} v.1= TBh  
(oxe\Qk  
'D-#,X C  
Utility.log(nFileLength); yvxC/Jo4  
6QRfju'  
=3=KoH/'  
return nFileLength; zJMKgw,i*  
} l\^q7cXG  
LeW.uh3.  
qD\%8l.]Z  
//保存下载信息(文件指针位置) (nrrzOax  
private void write_nPos() co3H=#2a  
{ \i-jME(sN  
try{ =tcPYYD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *eXO?6f%s^  
output.writeInt(nStartPos.length); ^c]Sl  
for(int i=0;i<nStartPos.length;i++) L\og`L)5\  
{ B>?Y("E  
// output.writeLong(nPos); &Jj> jCg  
output.writeLong(fileSplitterFetch.nStartPos); E|9LUPcb  
output.writeLong(fileSplitterFetch.nEndPos); YeJ95\jf  
} g]xZ^M+  
output.close(); 6\,^MI  
} ) WIlj  
catch(IOException e){e.printStackTrace ();} FbM5Bqv  
catch(Exception e){e.printStackTrace ();} ^@L[0Z`  
} L1QQU  
]@J}f}Mjo  
@` .u"@  
//读取保存的下载信息(文件指针位置) !BEOeq@2.  
private void read_nPos() U>;itHW/  
{ ?<frU ,{  
try{ T *t$   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /^[)JbgB  
int nCount = input.readInt(); H>XbqIkL@  
nStartPos = new long[nCount]; %Z{J=  
nEndPos = new long[nCount]; ~v>w%]  
for(int i=0;i<nStartPos.length;i++) e( ^9fg_SG  
{ (&MSP  
nStartPos = input.readLong(); :e@JESlLf  
nEndPos = input.readLong(); 8VcAtrx_  
} R~*Y@_oD  
input.close(); r-YQsu&  
} Vd<= y  
catch(IOException e){e.printStackTrace ();} [bPE?_a,  
catch(Exception e){e.printStackTrace ();} J-PzIFWd  
} <vt^=QA'  
)dL?B9d:  
rF0zGNH  
private void processErrorCode(int nErrorCode) ($(1KE  
{ *vAOUqX`x  
System.err.println("Error Code : " + nErrorCode); g&0GO:F`  
} 4_.k Q"'DH  
J|FyY)_  
?XOeMI  
//停止文件下载 T %a]3  
public void siteStop() j|G-9E  
{ oZCi_g 5i  
bStop = true; g41Lh3dj  
for(int i=0;i<nStartPos.length;i++) gy =`cMS@  
fileSplitterFetch.splitterStop(); `4EOy:a  
z~ u@N9M  
!RcAJs'  
} T (2,iG8  
} y]jh*KD[  
//负责部分文件的抓取 '*,4F'  
**FileSplitterFetch.java j [U0,]  
*/ c?R.SBr,'  
package NetFox; _TPo=}Z  
jATU b-  
H4:TYh  
import java.io.*; 6$6NVq  
import java.net.*; ESrWRO f9  
rFy9K4D  
Na~_=3+a  
public class FileSplitterFetch extends Thread { wO!hVm,T a  
Y!7P>?)`,X  
k(qQvn  
String sURL; //File URL 2mlE;.}8  
long nStartPos; //File Snippet Start Position C(0Iv[~y/  
long nEndPos; //File Snippet End Position =hs@W)-O  
int nThreadID; //Thread's ID PRz oLzr  
boolean bDownOver = false; //Downing is over %xZ.+Ff%  
boolean bStop = false; //Stop identical F{"%ey">  
FileAccessI fileAccessI = null; //File Access interface /MU<)[*Ro  
>(*jbL]p  
#wjBMR%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .FXQ,7mZ-  
{ f.P( {PN  
this.sURL = sURL; w%_BX3GTO  
this.nStartPos = nStart; ,?d%&3z<a  
this.nEndPos = nEnd; 8_,ZJ9l ;  
nThreadID = id; V[xy9L[#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _(z"l"l=$  
} R]Yhuo9,&n  
Azle ;\l`  
}1W$9\%  
public void run() y*(YZzF  
{ ]s -6GT  
while(nStartPos < nEndPos && !bStop) K`X2N  
{ ww,c)$  
4B y-+C*  
_[ phs06A  
try{ eLYFd,?9  
URL url = new URL(sURL); jF;4 8g@^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OWjZ)f/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8 KkpXaz  
String sProperty = "bytes="+nStartPos+"-"; Vx*q'~4y!|  
httpConnection.setRequestProperty("RANGE",sProperty); h^0mjdSp,  
Utility.log(sProperty); 4AM*KI  
!qpu /  
P8VU&b\  
InputStream input = httpConnection.getInputStream(); `l+SJLyJ%  
//logResponseHead(httpConnection); LX fiSM{o  
Ww(_EW  
<di_2hN  
byte[] b = new byte[1024]; i`SF<)M(  
int nRead; 31* 6 ;(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JJ~?ON.H  
{ \+u qP:Ty  
nStartPos += fileAccessI.write(b,0,nRead); biG9?  
//if(nThreadID == 1) 84[^#ke  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r9Z/y*q  
} u7=[~l&L  
'JMa2/7CG  
$a A.d^  
Utility.log("Thread " + nThreadID + " is over!"); 1;P\mff3Y  
bDownOver = true; `aUp&8{  
//nPos = fileAccessI.write (b,0,nRead); <C$<(Dw5  
} 4PWr;&  
catch(Exception e){e.printStackTrace ();} =vc5,  
} 6\3k0z  
} ]1&9~TL  
RF)B4D-W  
88>Uu!M=f  
//打印回应的头信息 1,j9(m2  
public void logResponseHead(HttpURLConnection con)  {K9E% ,w  
{ %jxuH+L   
for(int i=1;;i++) V8yX7yx  
{ a+/|O*>#  
String header=con.getHeaderFieldKey(i); I{zE73  
if(header!=null) AuTplO0_rE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k^pu1g=6I  
Utility.log(header+" : "+con.getHeaderField(header)); j>*SJtq7  
else 6Qb)Uq3}]  
break; \=7=>x_  
} %20-^&zZ  
} V@:=}*E  
M@g gLW  
f hG2  
public void splitterStop() RuNH (>Eb  
{ LH#LBjOZk  
bStop = true; WWcm(q =  
} 2w|u)ow )  
KN:dm!A  
gVU\^KN]  
} mzxvfXSF  
tgtoK|.  
-0SuREn  
/* XOg(k(&T  
**FileAccess.java 0~b6wuFl  
*//文件访问(定位,写) ]8>UII,US  
package NetFox; k^5R f  
import java.io.*; @Q\$dneY  
2Lekckgv  
\G=R hx f  
public class FileAccessI implements Serializable{ (l8r>V  
V 1nZ M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SE9u2Jk  
RandomAccessFile oSavedFile; $v<hW A]>  
long nPos; Usf"K*A  
csX*XiDWm  
G\>\VA  
public FileAccessI() throws IOException b/,!J] W  
{ i? _D]BY4  
this("",0); <<On*#80w  
} ;=VK _3"  
a^\- }4yR  
-)a_ub  
public FileAccessI(String sName,long nPos) throws IOException QjjJtKz  
{ sJI -  
oSavedFile = new RandomAccessFile(sName,"rw"); 2PP-0 E  
this.nPos = nPos; z?uQlm*We  
oSavedFile.seek(nPos); %{~mk[d3  
} b|ksMB>)  
&Wv`AoV  
=PKt09b^  
public synchronized int write(byte[] b,int nStart,int nLen) <x0uO  
{ @7l=+`.i  
int n = -1; -=Eq/s u%  
try{ &>zy_)  
oSavedFile.write(b,nStart,nLen); ?fa,[r|G  
n = nLen; l`FR.)2h  
} aEFe!_QY  
catch(IOException e) w HHF=Q  
{ QV'3O|  
e.printStackTrace (); a[P>SqT4`  
} ;TV'PJ  
%<J(lC9,C  
Kjn&  
return n; \B>[je-d  
} )_X xk_  
t`8e#n 9  
\|pK Z6*s  
} wO_pcNYZ8  
A.$VM#  
RZ)vU'@kx  
/* 1f@U :<:  
**SiteInfoBean.java d%_78nOh"  
*/ $-fjrQ  
package NetFox; {F(-s"1;xO  
$O~F>.*  
K+ 7yUF8XP  
public class SiteInfoBean { ,LW(mdIe(  
s9_`Wrg?  
/[nZ#zj!3  
private String sSiteURL; //Site's URL cEdz;kbUM  
private String sFilePath; //Saved File's Path *<.WL"Qhl  
private String sFileName; //Saved File's Name Yn$>QS 4  
private int nSplitter; //Count of Splited Downloading File SD|4ybK>d  
c5iormb"#  
m.HX2(&\3  
public SiteInfoBean() -@ UN]K  
{//nSplitter的缺省值为5 J]|6l/i  
//default value of nSplitter is 5 K.#,O+-Kg`  
this("","","",5); / UaNYv/  
} C6D=>%uY  
liCCc;&B;  
RQ*|+ ~H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !4 4mT'Y  
{ 7SA-OFM  
sSiteURL= sURL; TRySl5jx@  
sFilePath = sPath; :_fjml/  
sFileName = sName; p;n3`aVh  
this.nSplitter = nSpiltter; XC7Ty'#"KX  
n $O.>  
+9 16ZPk  
} qUEd E`B  
iJdrY 6qd  
JI+KS  
public String getSSiteURL() ^:cb $9F  
{ wv7p,9Z[  
return sSiteURL; OXIu>jF  
} H)j [eZP  
_>jrlIfc  
;9p#xW6  
public void setSSiteURL(String value) =q"w2b&  
{ ]uStn   
sSiteURL = value; U!a!|s>  
} [U%ym{be ^  
je- , S>U  
M!&_qj&N,  
public String getSFilePath() HIPcZ!p  
{ IFC%%I t5,  
return sFilePath; 0.J1!RIK/  
} {FV,j.D  
dJ%wVY0z=  
VVI8)h8  
public void setSFilePath(String value)  fW5" 4,  
{ !7mvyc!'!  
sFilePath = value; k\+y4F8$x  
} u@=+#q~/P  
Q*09 E  
_XY`UZ  
public String getSFileName() <K DH  
{ Nl=m'4 @`  
return sFileName; ]= ?X*,'  
} P S_3Oq)  
1qm/{>a-  
 l5ZADK4  
public void setSFileName(String value) 097Fvt=#  
{ #L@} .Giz  
sFileName = value; pW*{Mx  
} vi[#? ;pkF  
g{g`YvLu^  
gZ`32fB%  
public int getNSplitter() Gsds!z$  
{ q:`77  
return nSplitter; pgz:F#>  
} klK-,J  
#;\L,a|>*  
p|&ZJ@3  
public void setNSplitter(int nCount) vHs>ba$"  
{ 0%;N9\  
nSplitter = nCount; iX8h2l  
} a' IX yj  
} ou<S)_|Iu  
Fe_::NVvk  
jgo e^f  
/* 6)=](VmNL`  
**Utility.java ffmG~$Yh_  
*/ 8N=%X-R%  
package NetFox; H$NP1^5!  
rmY,v  
]Y_{P~ZX  
public class Utility { \GijNn9ah  
-:)DX++  
Nk lz_ ]  
public Utility() 4o1Q7  
{ ( GFgt_  
:3111}>c  
i&A{L}eCr:  
} |Hx%f  
K(-G: |  
//线程睡眠 fkdf~Vb  
public static void sleep(int nSecond) Y5n z?a  
{ #5'c\\?Q  
try{ 8q_1(& O  
Thread.sleep(nSecond); lTa1pp Zw  
} qg^(w fI  
catch(Exception e) d4jVdOq2  
{ ry$tK"v/  
e.printStackTrace (); Hfh@<'NL]  
} [GtcaX{Zz  
} Oq #o1>  
<'r0r/0g?  
//日志 Dl0/-=L  
public static void log(String sMsg) NzjMk4t  
{ WuBmdjZ  
System.err.println(sMsg); "sFW~Y  
} 4 hL`=[AB  
"V:   
*,E;  
public static void log(int sMsg) k%{ l4  
{ K5P Gi#  
System.err.println(sMsg); JzHqNUn*M  
} Z1VC5* K  
} W;^Rx.W  
G1kDM.L  
o^6jyb!j  
/* &J\B\`  
**TestMethod.java 3Z_t%J5QZ$  
*/ [_j6cj]  
package NetFox; :9(3h"  
`2>XH:+7F  
 `>%-  
public class TestMethod { 7;^((.]ln  
7*+Km'=M  
YkSuwx@5_q  
public TestMethod() ZH\0=l)  
{ ///xx/weblogic60b2_win.exe uK"^*NEC';  
try{ -oU@D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xcHen/4X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); DYc.to-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9~=gwP  
fileFetch.start(); 4S'[\ZJO  
} E3y6c)<  
catch(Exception e){e.printStackTrace ();} U?^OD  
lco~X DI  
^SEc./$  
} IDj_l+?c  
p`\3if'  
>H$;Z$o*(  
public static void main(String[] args) A_@I_V$  
{ FH4u$ g+  
new TestMethod(); a|U}Ammr  
} I=U+GY:  
} l(gJLjTH%  
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