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http断点续传简单实现(java)

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/* q8>t!rh<R  
**SiteFileFetch.java IkDiT63]I  
*/ o5swH6Y.)J  
package NetFox; iA'As%S1  
import java.io.*; bb;(gK;F  
import java.net.*; bO3GVc+S  
dU]/$7  
JJ ?I>S N!  
public class SiteFileFetch extends Thread { ?^u^im  
2.-o@im0  
?mx\eX{  
SiteInfoBean siteInfoBean = null; //文件信息Bean +-BwQ{92[:  
long[] nStartPos; //开始位置 (}smW_ `5  
long[] nEndPos; //结束位置 [Atc "X$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Nu^p  
long nFileLength; //文件长度 83 I-X95  
boolean bFirst = true; //是否第一次取文件 pJBg?D  
boolean bStop = false; //停止标志 Nxk(mec"  
File tmpFile; //文件下载的临时信息 $6h*l T<  
DataOutputStream output; //输出到文件的输出流 J;}3t!  
?Ik4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) M;jcUX_{  
public SiteFileFetch(SiteInfoBean bean) throws IOException (ChD]PWQ  
{ SV.z>p  
siteInfoBean = bean; &!L:"]=+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P4k;O?y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /_t|Dry015  
if(tmpFile.exists ()) Y$<D9f s3  
{ pKT2^Q}-h  
bFirst = false; ]Gv!M?:  
read_nPos(); RWKH%C[Yd  
} FhkkW W L  
else 3mO;JXd  
{ c_.-b=zm  
nStartPos = new long[bean.getNSplitter()]; 9QwKakci  
nEndPos = new long[bean.getNSplitter()]; mwC=o5O  
} ''H"^oS  
SeEw.;Xw  
n~.*1. P  
%m&@o~+  
} &~~wX,6+  
&nj&:?w  
}%TPYc  
public void run() Lrd[O v  
{ hyg8wI  
//获得文件长度 DM{ 4@*]  
//分割文件 ,"\@fwy{  
//实例FileSplitterFetch S`!-Cal`n  
//启动FileSplitterFetch线程 -!e7L>w  
//等待子线程返回 s?rBE.g@}  
try{ ZnW@YC#9  
if(bFirst) W*N$'%  
{ Bv6 K$4  
nFileLength = getFileSize(); By)u-)g9  
if(nFileLength == -1) k; ZxY"^  
{ 4x;_AN  
System.err.println("File Length is not known!"); ABh&X+YD  
} !w39FfU{  
else if(nFileLength == -2) p{D4"Qn+P9  
{ ;dR=tAf0$Q  
System.err.println("File is not access!"); ?D`T7KSe~D  
} ?6^|ZtB  
else T,%j\0  
{ K`g7$r)U[  
for(int i=0;i<nStartPos.length;i++) ?jx1R^  
{ p-GAe,2q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T;5r{{  
} )%d*3\Tsd  
for(int i=0;i<nEndPos.length-1;i++) ntVS:F  
{ vBcq_sbo  
nEndPos = nStartPos[i+1]; Pe;Y1Qq>>  
} eE GfM0  
nEndPos[nEndPos.length-1] = nFileLength; vy9 w$ls  
} jszK7$]^  
} [ic870_  
O@V%Cu  
r!PpUwod  
//启动子线程 Z?5V4F:f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =O).Lx2J  
for(int i=0;i<nStartPos.length;i++) "A$!, PX6  
{ ` Ag{)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), **3 z;58i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9iUrnG*  
nStartPos,nEndPos,i); q 11IkDa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p Z: F:  
fileSplitterFetch.start(); TS2ZF{m  
} Uu 8,@W+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #Lv2Zoi>G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4db(<h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *z*uEcitW  
nEndPos = " + nFileLength); c2t=_aAIPQ  
// fileSplitterFetch[nPos.length-1].start(); j>-gO,v, y  
4%nE*H%  
F8:vDv  
//等待子线程结束 Zwz&rIQpT  
//int count = 0; ",7Q   
//是否结束while循环 C?Bl{4-P}*  
boolean breakWhile = false; #|&Sc_#4)  
!$-\;<bZw  
YG [;"QR  
while(!bStop) #9-P%%kQ  
{ U4aU}1RKz  
write_nPos(); /='. 4 v  
Utility.sleep(500); ]vWKR."4  
breakWhile = true; VXIP0p@  
z|EEVNFd&  
Y2o?gug  
for(int i=0;i<nStartPos.length;i++) $6OkIP.  
{ WmY``  
if(!fileSplitterFetch.bDownOver) VCXJwVb  
{ }by;F9&B  
breakWhile = false; S}p4iE"n  
break; .ZvM^GJb  
} ![]`` g2  
} i;LXu%3\  
if(breakWhile) z9FfU  
break; 35E_W>n  
:8CvRO*<  
1$M@]7e+!+  
//count++; wr[,  
//if(count>4) \b%kf99  
// siteStop(); ^6_e=jIN  
} UfN&v >8f  
h4q|lA6!k8  
z!l.:F  
System.err.println("文件下载结束!"); .pvi!NnL-  
} &?mD$Eo  
catch(Exception e){e.printStackTrace ();} Ty vtmx M  
} ?c[*:N(  
o.0ci+z@  
QUu}Xg:  
//获得文件长度 G:~k.1y[  
public long getFileSize() nqInb:  
{ GGnpjwXeH  
int nFileLength = -1; \"X!2  
try{ tjupJ*Rt  
URL url = new URL(siteInfoBean.getSSiteURL()); C:PMewn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O3I8k\`  
httpConnection.setRequestProperty("User-Agent","NetFox"); :<}=e@/~|  
n4}B r;%  
?b(=1S\E'^  
int responseCode=httpConnection.getResponseCode(); ?VP8ycm  
if(responseCode>=400) "jG}B.l=,  
{ G6T_O  
processErrorCode(responseCode); xuqv6b.  
return -2; //-2 represent access is error a)wJT`xu  
}  ,%uo6%  
{zMU#=EC  
"?V0$-DR  
String sHeader; |&RU/a  
&YF^j2  
1v71rf&w  
for(int i=1;;i++) "rx-_uK*  
{ O^oWG&Y;v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vQ;Ex  
//Utility.log(in.readLine()); O8h%3&  
sHeader=httpConnection.getHeaderFieldKey(i); V5UF3'3;}  
if(sHeader!=null) ["h5!vj  
{ 9I&xfvD,  
if(sHeader.equals("Content-Length")) nih0t^m'  
{ i\,-oO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7Zlw^'q$:L  
break; M7pOLP_1jB  
} B}lvr-c#  
} u6AA4(  
else 5`~PR :dN  
break; x[a<mk  
} vN`klDJgW[  
} ibj87K  
catch(IOException e){e.printStackTrace ();} vX/T3WV  
catch(Exception e){e.printStackTrace ();}  C uB`CI  
!@}wDt  
I}1NB3>^  
Utility.log(nFileLength); wOU_*uY@6'  
kM,C3x{A  
9[<)WQe6M  
return nFileLength; RW<D<5C  
} <g"{Wv: h  
Y$"O VC  
%5(I/zB  
//保存下载信息(文件指针位置) jYk&/@`Ly  
private void write_nPos() Dfmjw  
{ hb}+A=A=+  
try{ ynthDE o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;lE%M  
output.writeInt(nStartPos.length); E|iQc8gr&  
for(int i=0;i<nStartPos.length;i++) F(>Np2oi6  
{ .+$ Q<L  
// output.writeLong(nPos); <3LbN FP  
output.writeLong(fileSplitterFetch.nStartPos); YtmrRDQs  
output.writeLong(fileSplitterFetch.nEndPos); GPN]9  
} e|"WQ>  
output.close(); Y3Yz)T}UkS  
} yDzc<p\`  
catch(IOException e){e.printStackTrace ();} LRL,m_gt  
catch(Exception e){e.printStackTrace ();} VK m&iidU  
} '=b/6@&  
{*G9|#[/@  
].-1v5  
//读取保存的下载信息(文件指针位置) h`^jyoF"(  
private void read_nPos() dYJ(!V&  
{ y [}.yyye  
try{ 0XE4<U   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); eA2@Nkw~)  
int nCount = input.readInt(); %)1y AdG 8  
nStartPos = new long[nCount]; rC5 p-B%  
nEndPos = new long[nCount]; ,E S0NA  
for(int i=0;i<nStartPos.length;i++) C5o#i*|  
{ Cd#(X@n  
nStartPos = input.readLong(); Bs^aII$  
nEndPos = input.readLong(); *4\:8  
} ua3~iQj-  
input.close(); !fE`4<|?  
} "\: `/k3  
catch(IOException e){e.printStackTrace ();} +r2+X:#~T  
catch(Exception e){e.printStackTrace ();} ]d$8f  
} "@V Y  
j()7_  
hOjk3 k  
private void processErrorCode(int nErrorCode) oB(?_No7  
{ ,Vc6Gwm  
System.err.println("Error Code : " + nErrorCode); _kef 0K6  
} ]L5@,E4.  
=^M/{51j  
L/$H"YOv  
//停止文件下载 glO^yZs  
public void siteStop() Ag-(5:  
{ , qMzWa  
bStop = true; XO.jl"xu  
for(int i=0;i<nStartPos.length;i++) slCx w$  
fileSplitterFetch.splitterStop(); }Y12  
n(1l}TJy  
@LF,O}[2J  
} R0KPZv-  
} .s?L^Z^  
//负责部分文件的抓取 PxvyN_B#>  
**FileSplitterFetch.java P) Jgs  
*/ ]C!gQq2'a  
package NetFox; u-QB.iQ+s  
ha]VWt%}  
]E5o1eeg  
import java.io.*; WlOmJtt4)  
import java.net.*; BtkOnbz8X  
Ri<u/ ]oR"  
)1?y 8_B  
public class FileSplitterFetch extends Thread { 3Z>Ux3[  
r8`ffH  
|mZxfI  
String sURL; //File URL Ytn9B}%o  
long nStartPos; //File Snippet Start Position xG~P+n7t5$  
long nEndPos; //File Snippet End Position ER%^!xA  
int nThreadID; //Thread's ID [_BP)e  
boolean bDownOver = false; //Downing is over d[iQ` YW5  
boolean bStop = false; //Stop identical bV^rsJm  
FileAccessI fileAccessI = null; //File Access interface x]}^v#  
/CrSu  
uy>q7C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lU8l}Ndz"  
{ T$8)u'-pa  
this.sURL = sURL; (~p< P+  
this.nStartPos = nStart; ; 5*&xz  
this.nEndPos = nEnd; )3cAQ'w  
nThreadID = id; j\eI0b @*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ">\?&0  
} 'g}!  
<$D`Z-6  
=*oJEy"  
public void run() N=V==Dbu-  
{ 2=*H 8'k  
while(nStartPos < nEndPos && !bStop) OAgniLv  
{ 9SX +  
AP3a;4Z#  
ahusta  
try{ y6g&Y.:o  
URL url = new URL(sURL); >xN .F/[K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A7%)~z<  
httpConnection.setRequestProperty("User-Agent","NetFox"); NDN7[7E  
String sProperty = "bytes="+nStartPos+"-"; nGC/R&  
httpConnection.setRequestProperty("RANGE",sProperty); &h}#HS>l  
Utility.log(sProperty); %Hu5K>ZNYp  
VF+KR*  
Sj3+l7S?  
InputStream input = httpConnection.getInputStream(); p?02C# p  
//logResponseHead(httpConnection); l[dK[4  
wo3d#=   
 eb ?x9h  
byte[] b = new byte[1024]; &sl0W-;0  
int nRead; w2?3wrP3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >R'F,  
{ ?e%ZOI  
nStartPos += fileAccessI.write(b,0,nRead); lt/1f{v[:  
//if(nThreadID == 1) 1y:-N6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]}V<*f  
} 0 j^Kgx  
B`EJb71^Xy  
9=s<Ld  
Utility.log("Thread " + nThreadID + " is over!"); ko!)s  
bDownOver = true; R!HXhQ  
//nPos = fileAccessI.write (b,0,nRead); W~)}xy  
} 21n?=[  
catch(Exception e){e.printStackTrace ();} v_yw@  
} t$`r4Lb9/  
} `~cqAs}6]Q  
F/ ]2G^-  
 \__i  
//打印回应的头信息 aEB_#1  
public void logResponseHead(HttpURLConnection con) <;lkUU(WT2  
{ b]e"1Y)D-  
for(int i=1;;i++) A@`}c,G  
{ L7l FtX+b  
String header=con.getHeaderFieldKey(i); =0 #O U  
if(header!=null) 11NQR[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9p]QM)M  
Utility.log(header+" : "+con.getHeaderField(header)); wH*-(*N "  
else 7 W5@TWM  
break; jV i) Efy  
} td$E/h=3  
} IYv`IS"  
x5pdS:  
_T60;ZI+^  
public void splitterStop() 'B |JAi?  
{ 6%'QjwM_  
bStop = true; MxKS4k  
} /l3V3B7  
GblA9F7  
Y/F6\oh  
} 8|gIhpO?^  
[+Iz@0q  
Zpt\p7WQ  
/* *VCXihgo  
**FileAccess.java $t+,Tav  
*//文件访问(定位,写) Dm981t>wL  
package NetFox; 10Q ]67  
import java.io.*; !aUs>1i  
i$Ul(?  
-OV&Md:~  
public class FileAccessI implements Serializable{ yxPazz  
2Ah#<k-gC;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {p2!|A&a  
RandomAccessFile oSavedFile; hE{K=Tz$  
long nPos; A`%k:@  
U gat1Pz  
g&L!1<, p  
public FileAccessI() throws IOException 70?\ugxA  
{ Z-%\ <zT  
this("",0); ic:zsuEm  
} b`Zx!^  
M/f<A$xx_  
#~]zhHI  
public FileAccessI(String sName,long nPos) throws IOException 'ms-*c&  
{ }rUN_.n4z  
oSavedFile = new RandomAccessFile(sName,"rw"); |"}FXa O  
this.nPos = nPos; "S[450%  
oSavedFile.seek(nPos); (MM]N=Tw4  
} yZY\MB/  
qz_7%c]K[  
iQ67l\{R  
public synchronized int write(byte[] b,int nStart,int nLen) )MVz$h{c.]  
{ Pm6p v;WK  
int n = -1; K-)] 1BG  
try{ (XTG8W sN  
oSavedFile.write(b,nStart,nLen); ;fTKfa  
n = nLen; HQdxL*N%^  
} FjHv   
catch(IOException e) z _$%-6  
{ BKCiIfkZ  
e.printStackTrace (); 5Pc;5 o0C  
} au(D66VO  
r8?gD&c}  
8 /]S^'>  
return n; :LQYo'@yB  
} g/d<Zfq<{  
P= BZ+6DS  
EU 6oQ  
} KAJi  
2QcOR4_V  
&J]K3w1p  
/* Pbn*_/H  
**SiteInfoBean.java 1s&zMWC  
*/ WDYeOtc  
package NetFox; tKuwpT1Qc  
"S]0  
X,% 0/6*]  
public class SiteInfoBean { 4"(Bu/24  
EWhK0Vej=  
9rX&uP)j^#  
private String sSiteURL; //Site's URL $99n&t$Y  
private String sFilePath; //Saved File's Path oCv.Ln1;Z  
private String sFileName; //Saved File's Name NR6#g,+7  
private int nSplitter; //Count of Splited Downloading File Wis~$"  
3pROf#M  
n38p!oS  
public SiteInfoBean() ub0.J#j@  
{//nSplitter的缺省值为5 Z clQ  
//default value of nSplitter is 5 <$$yw=ef  
this("","","",5); H2 {+)  
} u~:y\/Y6  
x_}:D *aI  
Mj3A5;#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h2A <"w  
{  qA7>vi%  
sSiteURL= sURL; k"%~"9  
sFilePath = sPath; K7B/s9/xs  
sFileName = sName; |Zpfq63W  
this.nSplitter = nSpiltter; *;slV3  
+o{R _  
M/'sl;  
} [S%_In   
?3,:-"(@p  
.VJMz4$]O  
public String getSSiteURL() CsR$c,8X.  
{ 1=c\Rr9]  
return sSiteURL; &{hL&BLr  
} L#{S!P,"  
re?,Wext\  
IPKbMlV#d  
public void setSSiteURL(String value) f*% D$Mqg  
{ SM#]H-3  
sSiteURL = value; i>A s;*  
} I*{ nP)^9  
g)[V(yWu  
*%NT~C q  
public String getSFilePath() /t57!&  
{ ~H_/zK6e  
return sFilePath; nNV'O(x}  
} =:Fc;n>c<K  
Fnv;^}\z  
}eU*( }<^  
public void setSFilePath(String value) ~ 'cmSiz-  
{ xh,qNnGGi  
sFilePath = value; \ a<h/4#|  
} k,6f &#x  
%@aSe2B  
"Yv_B3p   
public String getSFileName() .V/Rfq  
{ ::lKL  
return sFileName; wu!59pL  
} 33x{CY15  
bHYy}weZ  
X/!o\yyT  
public void setSFileName(String value) 6 7.+ .2  
{ [Td4K.c  
sFileName = value; `pa!~|p  
} {hjhL: pg  
%D34/=(X  
{SPq$B_VR  
public int getNSplitter() Oc#syfO  
{ tjGn|+|k  
return nSplitter; l"T44CL;  
} ]=I@1B;_m  
+F` S>U  
qvsd5PeCO  
public void setNSplitter(int nCount) W ]1)zO  
{ . B9iLI  
nSplitter = nCount; LVfF[  
} DB|Y  
} &K.d'$q  
]L $\ #  
3?9IJ5p  
/* YeL#jtC  
**Utility.java "@@u3`#  
*/ &< `NT D  
package NetFox; ?0?#U0(;u  
QB uMJm  
Ad8n<zt|  
public class Utility { wLH>:yKUU  
&*,#5.  
HxV=F66"  
public Utility() =E4LRKn  
{ "Mn6U-  
H>IMf/%5N-  
ay ;S4c/_  
} u@UMP@"#  
=,=A,kI[;  
//线程睡眠 /GN<\_o=q  
public static void sleep(int nSecond)  SI-qC  
{ )e+>w=t  
try{ ^z IW+:  
Thread.sleep(nSecond); F=e8IUr  
} 2!m/  
catch(Exception e) IGQaDFr  
{ 4#xDgxg\f  
e.printStackTrace (); T|eu  
} 9igiZmM  
} Q800y??&J  
n u[ML  
//日志 M*, -zGr  
public static void log(String sMsg) !qh]6%l  
{ ,{u yG:  
System.err.println(sMsg); <I\/n<*  
} Uw. `7b>B  
wPd3F.<$  
QUc= &5 %  
public static void log(int sMsg) ^R7lom.  
{ rdP[<Y9  
System.err.println(sMsg); 4{U T!WIi  
} ?%-DfCS  
} Eqd<MY7  
wedbx00o  
wr/"yQA]  
/* qZtzO2Mt  
**TestMethod.java !mJ"gg  
*/ v!6  c0a  
package NetFox; P6-s0]-g  
DS(}<HK{  
l'-Bu(  
public class TestMethod { s4y73-J^.v  
%~H-)_d20  
?}tFN_X"  
public TestMethod() kW Ml  
{ ///xx/weblogic60b2_win.exe p Z|V 3  
try{ x_N'TjS^{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (l~AV9!m:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !*d I|k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (&F}/s gbi  
fileFetch.start(); XH4  
} %+W{iu[|  
catch(Exception e){e.printStackTrace ();} r1`x=r   
|P HT694Uz  
f;o5=)Y  
} eCU:Q  
"Y =;.:qe  
.PIL +x*]N  
public static void main(String[] args) BDW^7[n  
{ X8a/ `Y,  
new TestMethod(); s^G.]%iU  
} A@!qv#'  
} 45@ I*`  
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