http断点续传简单实现（java)

/* Z4Q]By:/L  
**SiteFileFetch.java 0^S$_L  
*/ DcBAncsK  
package NetFox; O0jOI3/P%  
import java.io.*;  mhrF9&s  
import java.net.*; s.7=!JQ#]p  
%`
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public class SiteFileFetch extends Thread { `l'T/F\  
`PAQv+EYz  
|HT7m5tu4  
SiteInfoBean siteInfoBean = null; //文件信息Bean QBXEM=  
long[] nStartPos; //开始位置 m2^vH+wD  
long[] nEndPos; //结束位置 s?;8h &]=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9soEHG=P  
long nFileLength; //文件长度 *7H *ep
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boolean bFirst = true; //是否第一次取文件 roc DO8f  
boolean bStop = false; //停止标志 C~4SPCU  
File tmpFile; //文件下载的临时信息 E0RqY3  
DataOutputStream output; //输出到文件的输出流 {Ni]S$7  
4o M~  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Lqxhy s  
public SiteFileFetch(SiteInfoBean bean) throws IOException vrb@::sy0T  
{ 1_S]t[?I/  
siteInfoBean = bean; nZnqXclzxn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); TO89;O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); V~*>/2+  
if(tmpFile.exists ()) (U#,;  
{ G@Z%[YN
w  
bFirst = false; KF#^MEw%  
read_nPos(); I1m[M?  
} @P~%4:!Hr  
else dQSO8Jf  
{ Pa0W|q#?X  
nStartPos = new long[bean.getNSplitter()]; k%gj  
nEndPos = new long[bean.getNSplitter()]; TaSS) n  
} OWrQKd  
4GI3|{  
F%a&|X  
n.c0G`  
} eik_w(xPT  
bvh#Q_  
}v}F8}4  
public void run() ``<#F3  
{ !%M,x~H  
//获得文件长度 Q/3
*65  
//分割文件 5B|.cOE  
//实例FileSplitterFetch s"#N;  
//启动FileSplitterFetch线程 &'i_A%V  
//等待子线程返回 R98YGW_ dT  
try{ w;}5B~).  
if(bFirst) 'kj q C  
{ nG3SDL#(k  
nFileLength = getFileSize(); n\D/WLvM  
if(nFileLength == -1) B|a<=
~  
{ Dksn  
System.err.println("File Length is not known!"); Drtg7v{@\  
} M2ex 3
m  
else if(nFileLength == -2) G{6@]72  
{ )jl@hnA  
System.err.println("File is not access!"); Xj+_
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} I2HV{1(i  
else |~%RSS~b*  
{
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for(int i=0;i<nStartPos.length;i++) .S|T{DMQ[  
{  ij:a+T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `q]' ^EzJ  
} @mZK[*Ak<*  
for(int i=0;i<nEndPos.length-1;i++) nI?*[y
}  
{ j?*n@'   
nEndPos = nStartPos[i+1]; $!. [
R}  
} r4[=pfe25  
nEndPos[nEndPos.length-1] = nFileLength; Tv7W)?3h  
} K_Y{50#  
} 2~hdJ/  
jt}oq%Bf  
@1'OuX^  
//启动子线程 Z?xaXFm_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &TRKd)wd  
for(int i=0;i<nStartPos.length;i++) pD[&,gV$  
{ ~SBW`=aP}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9;XbyA]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [sG`D-\P[  
nStartPos,nEndPos,i); gYN;Fu-9Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XGR63hXND  
fileSplitterFetch.start(); K
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} "Cxj_V@\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 16eP
7s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [dLc+h1{B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `:Wyw<^  
nEndPos = " + nFileLength); _YR#J%xa  
// fileSplitterFetch[nPos.length-1].start(); eD7\,}O  
cHr]{@7Cs  
YIW9z{rrs  
//等待子线程结束 bE% Hm!  
//int count = 0; 'X+aYF}Ye  
//是否结束while循环 H#GR*4x  
boolean breakWhile = false; pW8?EGO@  
(9( xJ)  
%P1zb7:8  
while(!bStop) *IbDA  
{ Y<POdbg  
write_nPos(); z5({A2q  
Utility.sleep(500); vh"';L_*37  
breakWhile = true; #]+BIr`  
_5n2'\] H`  
FEhBhv|m  
for(int i=0;i<nStartPos.length;i++) rMWvW(@@D  
{ }` `oojz  
if(!fileSplitterFetch.bDownOver) PT,*KYF_O"  
{ zx"EAF{  
breakWhile = false; Bi fI.2|  
break; D_<B^3w)  
} < q(i(%  
} yD3vq}U!  
if(breakWhile) }mp`!7?>O  
break; sCy.i/y  
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=>Ae]mi7  
//count++; 4`v[p4k  
//if(count>4) ;;UsHhbhI  
// siteStop(); u*iqwm.  
} b*|?7  
|1ry*~  
QP<P,Bi~  
System.err.println("文件下载结束！"); moVf(7  
} #|769=1  
catch(Exception e){e.printStackTrace ();} ;w%g*S  
} q{*[uJ}Xc"  
L ~Vw`C  
V^qBbk%l>D  
//获得文件长度 :/? Op  
public long getFileSize() /:A239=+?  
{ gjT`<CW  
int nFileLength = -1; wMF1HT<*  
try{ 2\$<&]q  
URL url = new URL(siteInfoBean.getSSiteURL()); }1CO>a<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hHw1<! M  
httpConnection.setRequestProperty("User-Agent","NetFox"); aAoAjVNkK  
;/m>c{  
WR.7%U';  
int responseCode=httpConnection.getResponseCode(); {3vm]  
if(responseCode>=400) 6"?#s/fk  
{ &C,]c#-+  
processErrorCode(responseCode);
H!y@.W{_  
return -2; //-2 represent access is error @AG=Eq9<o  
} yF` (GU  
BI#(L={5  
?b^<Tny  
String sHeader; 0~<t :q!  
VasQ/  
]]V=\.y  
for(int i=1;;i++) q{,yas7}  
{ :1iXBG\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <9=RLENmY"  
//Utility.log(in.readLine()); (o6u^#6  
sHeader=httpConnection.getHeaderFieldKey(i); W#b++}S  
if(sHeader!=null) mMhe,8E&  
{ OB,T>o@  
if(sHeader.equals("Content-Length")) AsZyPybq  
{ /$vX1T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QBoX3w=  
break; &@7|_60  
} K1<l/ s  
} OZObx  
else < R@&<E6  
break; 2(D&jL  
} U_B`SS  
} A^c5CJ_  
catch(IOException e){e.printStackTrace ();} ; zy;M5l5.  
catch(Exception e){e.printStackTrace ();} mOjl0n[To]  
i3Nt?FSN  
+xmZK<{<  
Utility.log(nFileLength); 0XIrEwm@%  
gA
i}"};  
r:^`005  
return nFileLength; DUm/0q&  
} QQ,w:OjA0  
)>=|oY3  
)^^}!U#|e  
//保存下载信息（文件指针位置） ~>$(5s2  
private void write_nPos() ER$~kFE2yP  
{ kS7T'[d  
try{ }>j1j^c1='  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?~VevD  
output.writeInt(nStartPos.length); T5U(B3j_  
for(int i=0;i<nStartPos.length;i++) H @E-=Ly  
{ 8J9o$Se  
// output.writeLong(nPos); {24Pv#ZG#^  
output.writeLong(fileSplitterFetch.nStartPos); .Qj`_q6=  
output.writeLong(fileSplitterFetch.nEndPos); 0Zl1(;hx@  
} i%B$p0U<  
output.close(); ]Otl(\v(h  
} \=~<I  
catch(IOException e){e.printStackTrace ();} 1hp@.Fv  
catch(Exception e){e.printStackTrace ();} @1[LD[<  
} 9=~jKl%\vJ  
`V0]t_*D  
7 ~ Bo*UM  
//读取保存的下载信息（文件指针位置） lu.2ZQE
 
private void read_nPos() Ki@8  
{ Ix5yQgnB}j  
try{ C[$<7Mi|;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l}c<eEfOy"  
int nCount = input.readInt(); `wG&Cy]v  
nStartPos = new long[nCount]; 55|$Imnf  
nEndPos = new long[nCount]; g(;ejKSR  
for(int i=0;i<nStartPos.length;i++) ln!KL'T]  
{ }mJ)gK5b 6  
nStartPos = input.readLong(); B "}GAk}V  
nEndPos = input.readLong(); DFjkp;`1  
} tbk9N( R  
input.close(); )ZmE"  
} +
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catch(IOException e){e.printStackTrace ();} )'<zC  
catch(Exception e){e.printStackTrace ();} (/Y gcT  
} &q` =xF  
ZNA?`Z)f  
?,),%JQ  
private void processErrorCode(int nErrorCode) RMrt4:-DI  
{ gA) F  
System.err.println("Error Code : " + nErrorCode); uTJ?@^nq  
} \S2'3SDd/  
sQH.}W$C  
)d1,}o  
//停止文件下载 >"nk}@  
public void siteStop() j+ys&pDczm  
{ 1X9sx&5H  
bStop = true; n2O7n@8  
for(int i=0;i<nStartPos.length;i++) C,z]q$4  
fileSplitterFetch.splitterStop(); wLUmRo56aR  
>zhbipA  
O 1X !  
} ZmHl~MR@  
} /iQ>he~fy  
//负责部分文件的抓取 bKaV]Uy  
**FileSplitterFetch.java @+!d@`w:z2  
*/ 9_/1TjrDN  
package NetFox; D 7E^;W)H  
|)_<JAN  
!c`1~a!  
import java.io.*; jKQP0 t-  
import java.net.*; :{6[U=O  
nW%c95E  
+1623E  
public class FileSplitterFetch extends Thread { Gsh2  
dCyQCA[  
*:_hOOT+[  
String sURL; //File URL f3h9CV  
long nStartPos; //File Snippet Start Position Y\x Xo?  
long nEndPos; //File Snippet End Position Qqaf\$X  
int nThreadID; //Thread's ID J8D-a!  
boolean bDownOver = false; //Downing is over QBo^{],  
boolean bStop = false; //Stop identical tr}$82Po  
FileAccessI fileAccessI = null; //File Access interface z'I0UB#  
NV;tsuA|  
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T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6a!X`%N=  
{ VEZ/-s/  
this.sURL = sURL; fjJIF%  
this.nStartPos = nStart; *Ee# x!O  
this.nEndPos = nEnd; %qv7;E2C  
nThreadID = id; zC^Ib&gm>,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 g/yXPzLU  
} /L8=8  
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n#fg7d%  
public void run() 0?sp  
{ Aws TDM  
while(nStartPos < nEndPos && !bStop) ^YZ#P0 y  
{ MG@19R2s  
Dx%fW`  
8|/YxF<  
try{ x/<.?[A  
URL url = new URL(sURL); C!P6Z10+j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5-QXvw(TH  
httpConnection.setRequestProperty("User-Agent","NetFox"); w$!n8Aqs  
String sProperty = "bytes="+nStartPos+"-"; /L 4WWQ5  
httpConnection.setRequestProperty("RANGE",sProperty); "8X+F%  
Utility.log(sProperty); 'huLv(Uu  
RPWYm  
/ u{r5`4  
InputStream input = httpConnection.getInputStream(); M>#{
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//logResponseHead(httpConnection); >j?uI6Uw  
M@3H]t?  
zYNJF>^<  
byte[] b = new byte[1024]; XDGZqkt  
int nRead; ]9:G
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VQ;=-95P  
{ Xz@>sY>Jc  
nStartPos += fileAccessI.write(b,0,nRead); ( FRf.mv{  
//if(nThreadID == 1) l]Sui_+ZU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8K/lpqw  
} xl^'U/  
ZjK~s)RC  
;sf/tX  
Utility.log("Thread " + nThreadID + " is over!"); +A3H#'  
bDownOver = true; a*8}~p,  
//nPos = fileAccessI.write (b,0,nRead); HKwGaCj`  
} |"< I\Vs:  
catch(Exception e){e.printStackTrace ();} !|/fVWH  
} 
uI[*uAR  
} )em.KbsPPF  
Z0=OR^HjA  
-iHhpD9"X  
//打印回应的头信息 T_-MSXhA  
public void logResponseHead(HttpURLConnection con) KPhqD5, (  
{ *GhRU5  
for(int i=1;;i++) BTyVfq sx  
{ `<n:D`{dZ  
String header=con.getHeaderFieldKey(i); [C6?:'}FA  
if(header!=null) \zUsHK?L"t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NC}#P<U  
Utility.log(header+" : "+con.getHeaderField(header)); v
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else =.c"&,c?L  
break; vo-{3]u#=  
} ||=Duk  
} Ln|${c  
"q.uiz+1:  
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public void splitterStop() %U7B
0-  
{ hz%IxI9  
bStop = true; ap~Iz
  
} xTMTkVa+B  
;GSJnV  
?r<F\rBT7*  
} hd;I x%tq>  
$5r,Q{;$  
O@rb4(  
/* }TW=eu~  
**FileAccess.java !*gAGt_  
*//文件访问(定位，写) >``GDjcJ  
package NetFox; ,GIqRT4K  
import java.io.*; |Y11sDa9h  
`%3p.~>  
ErC[Zh"''  
public class FileAccessI implements Serializable{ Cj+=9Dc  
~~,<+X:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >lmL  
RandomAccessFile oSavedFile; P1n@E*~V5  
long nPos; _O%p{t'q<  
DG=Ap:sl*$  
h :R)KM  
public FileAccessI() throws IOException 0)!zhO_}  
{ ,be?GAq  
this("",0); ,m,vo_Ub  
} (xed(uFEK  
+.I'U9QeUN  
$4L3y uH  
public FileAccessI(String sName,long nPos) throws IOException {6sfa?1j  
{ Fr3t[:D  
oSavedFile = new RandomAccessFile(sName,"rw"); ".?{Y(~  
this.nPos = nPos; (K6StNtN  
oSavedFile.seek(nPos); ]s@8I2_  
} #7h fEAk  
V&H8-,7z  
Ui!|!V-  
public synchronized int write(byte[] b,int nStart,int nLen) w>_EM&r6~u  
{ nh)R  
int n = -1; `F8;{`a  
try{ w.p'Dpw  
oSavedFile.write(b,nStart,nLen); t8 "-zd8  
n = nLen; {W<-f?  
} jqWvLBU!  
catch(IOException e) ^6>|!  
{ =osw3"ng  
e.printStackTrace (); wf%Ep#^6}  
} A>A'dQ69  
>r3< O=Z7  
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return n; @0,dyg<$>  
}  a|uZJ*  
f"N3;,Oc  
{PtTPz  
} r$Y!Y#hwQ  
Ky$G$H  
d/rz0L  
/* LW5ggU/  
**SiteInfoBean.java 6JYOe  
*/ Gw^=kzh  
package NetFox; F5P{+z7  
D ;$+]2  
Zb;$
ZUWQX  
public class SiteInfoBean { O/oYaAlFF@  
Z8 %\v(L  
TR_oI<xB2  
private String sSiteURL; //Site's URL ItE~MJ5p  
private String sFilePath; //Saved File's Path .WyX/E$I^!  
private String sFileName; //Saved File's Name =[os<+  
private int nSplitter; //Count of Splited Downloading File h\\2r>  
Q$/FgS  
os^SD&hL  
public SiteInfoBean() M|e n>P  
{//nSplitter的缺省值为5 (Gc`3jJ  
//default value of nSplitter is 5 =3dbw8I  
this("","","",5); <|Eby!KXR  
} |S`yXsg  
'xoE [0!  
@k6}4
O?{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?9@Af{b t2  
{ \'tz|  
sSiteURL= sURL; $'{`i5XB  
sFilePath = sPath; vqz#V=J{  
sFileName = sName; -01 1U!  
this.nSplitter = nSpiltter; t0
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{}&f\6OI%  
Z;SG<  
} LE80`t>M#  
*1S.9L  
*Ne2l`!1m  
public String getSSiteURL() x~Ly$A2p  
{ Z)T@`B6  
return sSiteURL; ?V:]u
3  
} @ZR4%A"X4  
UH&1c8y}  
 / !  
public void setSSiteURL(String value) 0*/ r'  
{ !_H8Q}a  
sSiteURL = value; |SukiXJZF  
} He-Ja  
UJ)M:~
O  
O8~U<'=*  
public String getSFilePath() JX$NEq(  
{ AnE_<sPA  
return sFilePath; @3TkD_B&  
} qs1.@l("  
)/T$H|  
~K$"PKs3  
public void setSFilePath(String value) 7cP
[o+  
{ vJAAAS  
sFilePath = value; _.*4Y  
} :Z]hI
+7  
~7 L)n  
bo!]  
public String getSFileName() ~eOj:H  
{ 1L=Qg4 H  
return sFileName; s]<r  
} v\9,j  
cU5"c)$'  
2T(,H.O  
public void setSFileName(String value) IQi[g~E.5  
{ [(hvK{)  
sFileName = value; |
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} R ms
01m>Y  
} .H Fm'p  
E<#4G9O<  
public int getNSplitter() ZR-s{2sl  
{ CBnouKc:  
return nSplitter; u"8;fS  
} ~eV!!38 J  
+b,31  
xAd>",=~  
public void setNSplitter(int nCount)
m`\i+  
{ PVS<QN%  
nSplitter = nCount; )4L%zl7  
} :_QAjU  
} ^Im%D(MY  
uJ/?+5TU  
5ih"Nds[H  
/* !ga(L3vf  
**Utility.java :OQ:@Yk  
*/ #C,f/PXfaB  
package NetFox; bu"68A;>  
3+
8"  
,+f0cv4  
public class Utility { ZYA.1VrM  
7=p-A_X  
m!#)JFe67  
public Utility() M$]O=2h+2  
{ B`?N0t%X  
.xLF}{u  
C=dx4U~   
} '=Kof1  
C/CfjRzd  
//线程睡眠 gR-Qj  
public static void sleep(int nSecond) [#>$k 6F*  
{ ZP63Alt  
try{ o,Tr^e$  
Thread.sleep(nSecond); _+Jf.n20  
} EB29vHAt~  
catch(Exception e) dp[w?AMhM9  
{ e
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e.printStackTrace (); Id.Z[owC`Y  
} ;&W;  
} Yf!*OGF  
eb.cq"C  
//日志 @( n^S?(  
public static void log(String sMsg) 16[-3cJ T  
{ `Ge+(1x  
System.err.println(sMsg); jqX@&}3@  
} zOiY0`=  
/\-2l+y>J  
=,C
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public static void log(int sMsg) 3u?`q%Y-e  
{ y3KcM#[  
System.err.println(sMsg); E&];>3C  
} s=nVoc{Yt  
} ,h@R' f!  
mP)3cc5T  
{KU.  
/* znQ'm^h  
**TestMethod.java da00p-U  
*/ hSkc9jBF
 
package NetFox; W3jXZ>  
0tW<LR-}E  
Pn+IJ=0Y  
public class TestMethod { U50s!Zt45  
`s>UU- 9  
0j{F^rph  
public TestMethod() joChML_  
{ ///xx/weblogic60b2_win.exe O/DAf|X|  
try{ q4Oxs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cZDxsd]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9RCO|J  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %R.xS} Q  
fileFetch.start(); @ kJ0K  
} w*<Y$hnBzF  
catch(Exception e){e.printStackTrace ();} [:nx);\  
>k&8el6h  
Q$|^~  
} R,x>$n  
jJ*@5?A  
XdGpW  
public static void main(String[] args) J7'f@X~nM  
{ X!7VyE+n  
new TestMethod(); ] Wx>)LT  
} IP30y>\  
} S]e j=6SP  
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