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http断点续传简单实现(java)

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/* ),H1z`c&I  
**SiteFileFetch.java ,{_56j^d,  
*/ bl{W{?QI  
package NetFox; !Ej?9LHo  
import java.io.*; [LrO"9q(  
import java.net.*; zb s7G  
j Q8 T  
y5XFJj  
public class SiteFileFetch extends Thread { 92~$Qa\S!  
(a"/cH  
sGE %zCB  
SiteInfoBean siteInfoBean = null; //文件信息Bean OW#G{#.6R  
long[] nStartPos; //开始位置 ";^_[n  
long[] nEndPos; //结束位置 7Rd(,eWE@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qDgy7kkQ  
long nFileLength; //文件长度 5Rp mR  
boolean bFirst = true; //是否第一次取文件 bK{ VjXF  
boolean bStop = false; //停止标志 &'Xgf!x  
File tmpFile; //文件下载的临时信息 ?v`24p3PC  
DataOutputStream output; //输出到文件的输出流 JW"`i   
}GHC u  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ?5F;4 oR2g  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3 K q /V_  
{ ru|*xNXKgC  
siteInfoBean = bean; h-x~:$Z,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ED);2*qP}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \+&)9 !K  
if(tmpFile.exists ()) Pa"Kk9!o36  
{ Yp\Y]pym  
bFirst = false; ?1r<`o3l\  
read_nPos(); eI%k xqc  
} &q M8)2Y  
else (M{>9rk8  
{ . BX*C  
nStartPos = new long[bean.getNSplitter()]; TaF;P GjVw  
nEndPos = new long[bean.getNSplitter()];  QB !%  
} <U8w#dc  
2*] [M,L0c  
a'd=szt  
iiWpm E<,  
} Tl#2w=  
TD78&a#  
jvpv1>KYV  
public void run() F+L%Ho;@P  
{ . g-  HB'  
//获得文件长度 3Bcv"O,B!{  
//分割文件 X$?0C{@.}  
//实例FileSplitterFetch d(9-T@J  
//启动FileSplitterFetch线程 i 1Kq (7  
//等待子线程返回 \GKR(~f  
try{ 1H-~+lf  
if(bFirst) N#@v`S  
{ '8FHn~F  
nFileLength = getFileSize(); .v-2A);I  
if(nFileLength == -1) r]]:/pw?t  
{ BK wo2=m~  
System.err.println("File Length is not known!"); s'OK])>`  
} EVE"F'Ww,_  
else if(nFileLength == -2) &.PAIe.  
{ c= ?Tu  
System.err.println("File is not access!"); BqDsf5}jpA  
} JB=L{P J  
else 43<i3O  
{ |?hsMN  
for(int i=0;i<nStartPos.length;i++) 8k+k\V{  
{ `b%^_@Fb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D *IeG>%  
} L+eK)Q  
for(int i=0;i<nEndPos.length-1;i++) lkC|g%f  
{ Wtp=1  
nEndPos = nStartPos[i+1]; J|@D @\?7  
} 3o"l sly  
nEndPos[nEndPos.length-1] = nFileLength; +}Mm5^6*  
} ?.n1t@sG&  
} \j &&o  
<GLoTolZ  
",#Ug"|2  
//启动子线程  vNdW.V}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P>^$X  
for(int i=0;i<nStartPos.length;i++) jhBfy|Ftu  
{ P*OT&q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %!A-K1Z\D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), InRcIQT  
nStartPos,nEndPos,i); L3 KJ~LI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;0NJX)GL  
fileSplitterFetch.start(); J6ed  
} t< RPDQ>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kaaz,C.$^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ="P FCxi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XqwP<5Z  
nEndPos = " + nFileLength); .F[5{XV  
// fileSplitterFetch[nPos.length-1].start(); Wg<o%6`  
66$ hdT$  
DF'~ #G8  
//等待子线程结束 hlz/TIP^N3  
//int count = 0; 4/v[ .5  
//是否结束while循环 ~QUN O~  
boolean breakWhile = false; c%&*yR  
kuq&; uk$Q  
06v'!M  
while(!bStop) > %slzr  
{ }o\} qu*  
write_nPos(); 6Q{OM:L/;.  
Utility.sleep(500); mS49l  
breakWhile = true; HiD%BL>%  
$BG]is,&5  
f zL5C2d  
for(int i=0;i<nStartPos.length;i++) = C/F26=|  
{ } :gi<#-:G  
if(!fileSplitterFetch.bDownOver) [HQ/MkP-Z  
{ }_H\ 75Iv  
breakWhile = false; %?F$3YN,  
break; ^+gD;a|t  
} NzN"_ojM  
} NLUO{'uUW  
if(breakWhile) P{Q$(rOe  
break; *i!t&s  
] ;HCt=I~  
J4 U]_|  
//count++; ;Cjj_9e,:  
//if(count>4) dxH.  
// siteStop(); y(E<MRd8V  
} -Rr !J37  
V 'fri/Z  
8Z)wot  
System.err.println("文件下载结束!"); NS;L FeGD  
} bfpoX,:   
catch(Exception e){e.printStackTrace ();} 1N5lI97j  
} -.L )\  
09{s'  
U!E}(9 tb  
//获得文件长度 563ExibH  
public long getFileSize() N^k& 8  
{ 7{9M ^.}  
int nFileLength = -1; v yt|x5  
try{ < 'BsQHI  
URL url = new URL(siteInfoBean.getSSiteURL()); .CNwuN\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FPPl^  
httpConnection.setRequestProperty("User-Agent","NetFox"); rEbH< |  
.' h^  
oiD{Z  
int responseCode=httpConnection.getResponseCode(); ub+XgNO  
if(responseCode>=400) G|||.B 8  
{ pRUQMPn (  
processErrorCode(responseCode); 6z:/ma^  
return -2; //-2 represent access is error SwaPRAF  
} {.DY\;Q  
^+k= ;nl  
bqaj~:}@  
String sHeader; H]f[r~  
TefPxvd  
)HvB ceN  
for(int i=1;;i++) h-SKw=n  
{ 6Tc! =lk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E}<i?;  
//Utility.log(in.readLine()); ~&+a.@T  
sHeader=httpConnection.getHeaderFieldKey(i); eZ0-O /_i  
if(sHeader!=null) EB6X Yr  
{ <Z\{ijfvD  
if(sHeader.equals("Content-Length")) .M ID)PY-  
{ c6y>]8_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,dVJAV7v  
break; /FC(d5I  
} 8HHR  
} 7KJ0>0~Et  
else ={;+0Wjb8  
break; m}S}fH(  
} YD{N)v  
} ?{5}3a bB`  
catch(IOException e){e.printStackTrace ();} X|QokAR{$>  
catch(Exception e){e.printStackTrace ();} .])X.7@x  
 Vo%Z|  
c%(Nd i  
Utility.log(nFileLength); R|` `A5zQ  
A..`?oGj  
!,]c}Y{i  
return nFileLength; =^_a2_BBl  
} G2+ gEg  
$M+'jjnP  
u`Y~r<?P(  
//保存下载信息(文件指针位置) d\tY-X3  
private void write_nPos() FV,aQ#  
{ k `5K&  
try{ )|AxQPd  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SZ7; } r8  
output.writeInt(nStartPos.length); K@ &;f( Y  
for(int i=0;i<nStartPos.length;i++) ASr@5uFR  
{ AN|f:259  
// output.writeLong(nPos); %L wq.  
output.writeLong(fileSplitterFetch.nStartPos); %Y5F@=>&  
output.writeLong(fileSplitterFetch.nEndPos); 3f~znO  
} 2iOYC0`!  
output.close(); ]D=fvvST  
} tDfHO1pS  
catch(IOException e){e.printStackTrace ();} 475g-t2"@  
catch(Exception e){e.printStackTrace ();} #JXXq%4 @  
} UN:qE oS  
{K?e6-N(z  
>J)4e~9EJ2  
//读取保存的下载信息(文件指针位置) qEl PYN*wF  
private void read_nPos() vL^ +X`.td  
{ y=[{:  
try{ `>)pqI%L[g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !;hp  
int nCount = input.readInt(); i'^! SEt  
nStartPos = new long[nCount]; _ sy]k A  
nEndPos = new long[nCount]; up0=Y o@  
for(int i=0;i<nStartPos.length;i++) >g@@ yR,  
{ >B*zzj  
nStartPos = input.readLong(); ~,xso0  
nEndPos = input.readLong(); O'3/21)|y  
} 0($On`#  
input.close(); 6E^9>  
} }m7$,'C%P  
catch(IOException e){e.printStackTrace ();} )ZFc5m^+u  
catch(Exception e){e.printStackTrace ();} TqOH(= {  
} =En1?3?  
,Tk53 "  
zqZ/z>Gf  
private void processErrorCode(int nErrorCode) NmF8BmIj  
{ 2 &_>2"=<@  
System.err.println("Error Code : " + nErrorCode); &fU48n1Uh  
} NS*Lv  
YQD/vc~8G  
~@[<y1g?nG  
//停止文件下载 @l5GBsLK  
public void siteStop() 9jNh%raG|  
{ \b$Y_  
bStop = true; GJHJ?^%  
for(int i=0;i<nStartPos.length;i++) f;Ijl0d@  
fileSplitterFetch.splitterStop(); YRd`G3J  
>RpMw!NT  
yMD0Tj5ZQ  
} /V#? d  
} +V[;DOlll  
//负责部分文件的抓取 -pQ?ybQ  
**FileSplitterFetch.java -C!m#"PDW  
*/ giW9b_  
package NetFox; I }8b]  
1\)lD(J\C  
g@Y]$ey%A  
import java.io.*; kVG+Wr7l0F  
import java.net.*; K*4ib/'E a  
t'.:"H8BI  
yw89*:A6  
public class FileSplitterFetch extends Thread { [8oX[oP  
Dqd2e&a\  
\0&$ n  
String sURL; //File URL %5@> nC?`[  
long nStartPos; //File Snippet Start Position Z$6B}cz<  
long nEndPos; //File Snippet End Position ];N/KHeZ  
int nThreadID; //Thread's ID PpF`0w=1%l  
boolean bDownOver = false; //Downing is over |)*!&\Ch  
boolean bStop = false; //Stop identical jJ,y+o  
FileAccessI fileAccessI = null; //File Access interface ,wv>G]v  
9JJ6$cLF  
s%6L94\t  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C^,J 6;'  
{ x;LO{S4Z  
this.sURL = sURL; b5f+q:?{  
this.nStartPos = nStart; -mLu!32I<  
this.nEndPos = nEnd; roe_H>  
nThreadID = id; <yvo<R^30  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B[+b%a3  
} u^WZsW  
_x,(576~  
/ZH*t\  
public void run() NJOV!\k  
{ 8E9k7  
while(nStartPos < nEndPos && !bStop) CoWT  
{ &SPr#OkW  
4E1j0ARQQ  
T eu.i   
try{ iQLP~Z>,T  
URL url = new URL(sURL); dP]Z:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K5??WB63B  
httpConnection.setRequestProperty("User-Agent","NetFox"); Kq+vAp).  
String sProperty = "bytes="+nStartPos+"-"; lE8_Q*ev  
httpConnection.setRequestProperty("RANGE",sProperty); Vf=,@7  
Utility.log(sProperty); 7vI ROK~  
QXEZ?gx  
6wXy;!2  
InputStream input = httpConnection.getInputStream(); X?/32~\  
//logResponseHead(httpConnection); _.%g'=14f  
n3 Rf:j^R  
lh!8u<yv*  
byte[] b = new byte[1024]; [TxvZq*4  
int nRead; .SSPJY(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HL:w*8a  
{ V!e*J,g  
nStartPos += fileAccessI.write(b,0,nRead); #$!^1yO  
//if(nThreadID == 1) ?g0dr?H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u^x<xw6f  
} Qp2~ `hD  
m"AyO"}I5  
=CCddLO  
Utility.log("Thread " + nThreadID + " is over!"); mJH4M9WJ]  
bDownOver = true; [[]NnWJ  
//nPos = fileAccessI.write (b,0,nRead); + EKp*Vje  
} LJt5?zQKrW  
catch(Exception e){e.printStackTrace ();} ,">CPl]  
} }wEt=zOJ  
} 0G+ qF96  
r'XWt]B+[  
T?`Ha\go  
//打印回应的头信息 zn|O)"C  
public void logResponseHead(HttpURLConnection con) vB5mOXGNq  
{ [?g}<fa  
for(int i=1;;i++) pK/RkA1  
{ yWr &G@>G  
String header=con.getHeaderFieldKey(i); r"\<+$ 7  
if(header!=null) GW%!?mJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *GdJ<B$  
Utility.log(header+" : "+con.getHeaderField(header)); %0 U@k!lP  
else 3jto$_3'w  
break; FR]uCH  
} <Oy2 JjY  
} aghlYcPg  
y'JJ#7O=  
zhyf}Ta'  
public void splitterStop() xr!A>q+@i  
{ ~i>'3j0@k  
bStop = true; |]-~yYqP3  
} eQqCRXx  
VjZb\ d4  
#ZHKq7  
} 6r[pOl:  
e%0IE X  
cwQ *P$n  
/* 6QPT  
**FileAccess.java B>cx[.#!  
*//文件访问(定位,写) \D#+0  
package NetFox; xq%BR[1  
import java.io.*; IQmlmu  
ktTP~7UVi  
NLL"~  
public class FileAccessI implements Serializable{ 23^>#b7st  
U; oXX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~bb6NP;'L  
RandomAccessFile oSavedFile; P5_Ajb(@'  
long nPos; { %X2K  
lF!PiL  
vNs%e/~vj  
public FileAccessI() throws IOException <<MpeMi  
{ gp`@dn';  
this("",0); ;(`bP  
} xE<H@@w  
~-7/9$ay5  
Ex p ?x  
public FileAccessI(String sName,long nPos) throws IOException {\1bWr8!U  
{ hTn"/|_SW  
oSavedFile = new RandomAccessFile(sName,"rw"); jerU[3  
this.nPos = nPos; Y%"$v0D  
oSavedFile.seek(nPos); bOr11?  
} a`w=0]1&*  
>E J{ *  
KUZi3\p9W>  
public synchronized int write(byte[] b,int nStart,int nLen) w CLniCt  
{ )Ac,F6w  
int n = -1; +S(# 7  
try{ 3/n?g7B  
oSavedFile.write(b,nStart,nLen); ?Xypn#OPt  
n = nLen; Y`ip. Nx  
} Bzwll  
catch(IOException e) /C!~v!;e  
{ kb2C 9<  
e.printStackTrace (); F-|DZ?)k5  
} u9S*2'  
}=bzUA`C  
Ly2,*\7  
return n; Y0,{fw<  
} 1sj7]G]`k  
*b) (-#w3  
l.pxDMY  
} 9abUh3  
a[~[l k=7  
GCN-T1HvA2  
/* Vp]7n!g4l  
**SiteInfoBean.java j? BL8E'   
*/ Q*#Lr4cm{  
package NetFox; ON\bD?(VY  
$EFS_*<X  
i;%G Z8  
public class SiteInfoBean { ! I?C8)  
2: gh q  
-"nkC  
private String sSiteURL; //Site's URL M 8WjqTq  
private String sFilePath; //Saved File's Path RG45S0Ygj  
private String sFileName; //Saved File's Name lF(v<drkB  
private int nSplitter; //Count of Splited Downloading File j67a?0<C2U  
9y6u&!PZ\  
LD[\eJ _  
public SiteInfoBean() GW>F:<p  
{//nSplitter的缺省值为5 GqCBD-@4v.  
//default value of nSplitter is 5 tjtvO@?1-  
this("","","",5); d {U%q d  
} +&G(AW  
|"LHo  H  
6NV592  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s 7 nl  
{ G]aey>)  
sSiteURL= sURL; ~Re4zU  
sFilePath = sPath; O.Pp*sQ^  
sFileName = sName; ++,I`x+p  
this.nSplitter = nSpiltter; A` _dj}UF  
}>@SyE'Q  
4Y59^  
} g$GGo[_0  
:} =lE"2  
[x{$f7CEh  
public String getSSiteURL() SV t~pE+Y  
{ PzKTEYJL  
return sSiteURL; u|IS7>Sm  
} =p.avAuSn  
FA-cTF[,(  
WZ ?>F  
public void setSSiteURL(String value) kfas4mkc  
{ *.nSv@F  
sSiteURL = value; HQ"T>xb  
} 'm*W<  
pl r@  
Gz{%Z$A~o  
public String getSFilePath() kB@gy}  
{ Lm}.+.O~d  
return sFilePath; ?=Ceo#Er  
} -b!Z(}JK  
^)]U5+g?  
F,S)P`?  
public void setSFilePath(String value) u=nd7:bv  
{ K.QSt  
sFilePath = value; M2cGr  
} Ti)Me-g  
5?H8?~&dz  
z# &1>  
public String getSFileName() 9cB+ x`+Lu  
{ 9oc_*V0<  
return sFileName; If'2 m_  
} L3\#ufytb  
ZbT$f^o}M]  
*yT>  
public void setSFileName(String value) h'em?fN(  
{ ')q4d0B`"  
sFileName = value; JqO1 a?H  
} J(}PvkA  
\VhG'd3k  
|qe;+)0>K  
public int getNSplitter() _(g0$vRP~  
{ ~-vCY  
return nSplitter; ,(q] $eOZ  
} grE(8M  
0#TL$?=|  
sTP\}  
public void setNSplitter(int nCount) 8?LT*>!  
{ 2Pm}wD^`  
nSplitter = nCount; TsT5BC63  
} kF^4kCJ@  
} pqO0M]}  
h%F.h![*  
9 l~D}5e7  
/* r}qDvC D  
**Utility.java py\:u5QS  
*/ Qqg.z-G%.  
package NetFox; (y; 6 H  
stK}K-=`  
0'6ai=W  
public class Utility { v@QnS  
9NwUX h(:(  
`l'T/F \  
public Utility() `PAQv+EYz  
{ jC[_uG  
Q(-&}cY  
8>WA5:]v  
} 5QK%BiDlr  
J/P[9m30[  
//线程睡眠 "|I.j)  
public static void sleep(int nSecond) $=diG  
{ hO[_ _j8  
try{ XgX~K:<jt  
Thread.sleep(nSecond); rkji#\_-FV  
} "XxmiK  
catch(Exception e) ^cNuEF9  
{ rM.Pc?Z  
e.printStackTrace (); _fZec+oM  
} @4UX~=:686  
} A^FkU  
hNh!H<}|m8  
//日志 D+:s{IcL<  
public static void log(String sMsg) nuWQ3w p[e  
{ VK*_p EV,}  
System.err.println(sMsg); @P~%4:!Hr  
} ?&9=f\/P  
*K_8=TIA*  
0IqGy}+VU  
public static void log(int sMsg) d6*84'|!  
{ >6yQuB  
System.err.println(sMsg); ^G`6Zg;  
} l4i 51S"  
} GdUsv  
<QvVPE}z   
RuYIG?J=/  
/* 67&IaDts  
**TestMethod.java X<IW5*   
*/ oS$7k3s fj  
package NetFox; 40MKf/9  
'.z7)n  
@2. :fK  
public class TestMethod { r e zp7  
&&l ZUR,`  
*cM=>3ws/  
public TestMethod() {1Cnrjw  
{ ///xx/weblogic60b2_win.exe 75p9_)>96  
try{ _!zc <&~I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +`wr{kB$~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UfPB-EFl$D  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7/a7p(   
fileFetch.start(); >b"@{MZ@t  
} ,N:^4A  
catch(Exception e){e.printStackTrace ();} ,w6?Ap  
X@[5nyILf  
iCpm^XT  
} X7OU=+g  
y _apT<P  
lHM} E$5  
public static void main(String[] args) 0~ nCT&V  
{ Z<>gx m<  
new TestMethod(); 7r?,wM  
} Y>aVnixx<  
} U/{t "e  
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