Archive for March 2009
Reading and writing fixed length records with Castor XML
I’ve been searching a generic Java tool in order to read and write fixed length records files with no success.
Traditionally, mainframe systems produce plain text files filled with fixed length records. Number records are filled with zeroes at the left (p.e. the fixed Number5 value 100 should be 00100) and String records are completed with blank spaces (p.e. the fixed String 5 value "abc" shoud be "abc "). So, this files may have the following aspect:
010011 CDOGenResCDW27032009
05001RES ACP 1 1 127032009
06001000000001Cosa1
06001000000002Cosa1
05999000000000004000000000002
05001RES REX 1 1 127032009
05999000000000002000000000000
01999000002000000000008
Read and write operations in Java over this type of plain files use to be tailored sentences using Java beans and formatter transformations. This technique can be a fast way to develop, but in my opinion decreases maintenance capabilities drastically.
Below a method to manage with plain files filled with fixed length records.
1. Develop an XSD to describe file contents
< ?xml version="1.0" encoding="UTF-8"?>
<xs_schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://cdwrecresfile.batch.cdocdw.net.lacaixa.es" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://cdwrecresfile.batch.cdocdw.net.lacaixa.es">
<xs_simpletype name="Numerico5">
<xs_restriction base="xs_long">
<xs_totaldigits value="5" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Numerico6">
<xs_restriction base="xs_long">
<xs_totaldigits value="6" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Numerico9">
<xs_restriction base="xs_long">
<xs_totaldigits value="9" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Numerico12">
<xs_restriction base="xs_long">
<xs_totaldigits value="12" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico1">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,1}" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico3">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,3}" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico8D">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,8}" />
<xs_pattern value="((0[1-9])|([12][0-9])|(3[01]))((0[1-9])|(1[012]))((000[1-9])|(00[1-9][0-9])|(0[1-9][0-9]{2})|([1-9][0-9]{3}))" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico8">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,8}" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico9">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,9}" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico12">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,12}" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico15">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,15}" />
</xs_restriction>
</xs_simpletype>
<xs_simpletype name="Alfanumerico1900">
<xs_restriction base="xs_string">
<xs_pattern value=".{0,1900}" />
</xs_restriction>
</xs_simpletype>
<xs_element name="CDWRecResFile">
<xs_complextype>
<xs_sequence>
<xs_element name="CabeceraFichero">
<xs_complextype>
<xs_sequence>
<xs_element name="codRegistro" type="Numerico5" fixed="01001"/>
<xs_element name="idAplicacion" type="Alfanumerico3"/>
<xs_element name="idInterface" type="Alfanumerico12" fixed="CDOGenResCDW"/>
<xs_element name="fechaProceso" type="Alfanumerico8D"/>
</xs_sequence>
</xs_complextype>
</xs_element>
<xs_element name="Respuesta" minOccurs="0" maxOccurs="unbounded">
<xs_complextype>
<xs_sequence>
<xs_element name="CabeceraRespuesta">
<xs_complextype>
<xs_sequence>
<xs_element name="codRegistro" type="Numerico5" fixed="05001"/>
<xs_element name="idTipoMensaje" type="Alfanumerico12"/>
<xs_element name="idSubTipoMensaje" type="Alfanumerico8"/>
<xs_element name="idSolicitud" type="Alfanumerico9"/>
<xs_element name="idCartaCredito" type="Alfanumerico15"/>
<xs_element name="idCliente" type="Alfanumerico1"/>
<xs_element name="fechaSolicitud" type="Alfanumerico8D"/>
</xs_sequence>
</xs_complextype>
</xs_element>
<xs_element name="DetalleRespuesta" minOccurs="0" maxOccurs="unbounded">
<xs_complextype>
<xs_sequence>
<xs_element name="codRegistro" type="Numerico5" fixed="06001"/>
<xs_element name="numLinea" type="Numerico9"/>
<xs_element name="textoXML" type="Alfanumerico1900"/>
</xs_sequence>
</xs_complextype>
</xs_element>
<xs_element name="PieRespuesta">
<xs_complextype>
<xs_sequence>
<xs_element name="codRegistro" type="Numerico5" fixed="05999"/>
<xs_element name="numLineas" type="Numerico12"/>
<xs_element name="numLineasXML" type="Numerico12"/>
</xs_sequence>
</xs_complextype>
</xs_element>
</xs_sequence>
</xs_complextype>
</xs_element>
<xs_element name="PieFichero">
<xs_complextype>
<xs_sequence>
<xs_element name="codRegistro" type="Numerico5" fixed="01999"/>
<xs_element name="numRespuestas" type="Numerico6"/>
<xs_element name="numRegistros" type="Numerico12"/>
</xs_sequence>
</xs_complextype>
</xs_element>
</xs_sequence>
</xs_complextype>
</xs_element>
</xs_schema>
Note. “xs:” replaced by “xs_” for visualization purpouses.
2. Use some marshalling tool to generate Java beans (Castor 1.1.1 for this example)
3. Write some useful read and write tools (only “interfaces” included in this post)
FileWriter.java
public interface FileWriter {
public FileWriter(String path, String fileName) throws IOException;
public void writeNext(String line) throws IOException;
public void endWrite();
}
FileReader.java
public interface FileReader {
public FileReader(String path, String fileName);
// Read one line
public String readNext() throws IOException;
public void gotoPosition(long position) throws IOException;
public void endRead() throws IOException;
public long getPreviousPosition();
}
LineWriter.java
public interface LineWriter {
public void addNumber(Object number, int length) throws Exception;
public void addString(Object string, int length) throws Exception;
public String getLine();
}
LineReader.java
public interface LineReader {
public LineReader(String line);
public String getString(int length);
public void reset();
public boolean isEnded();
public String getCurrentLine();
public int getCurrentPosition();
}
4. Core class to write and read plain files using Castor objects
/**
* Read and write plain text files filled with fixed width records using
* Castor objects that represent XSD files.
*/
public class BatchFile {
// Field length fixed by "pattern" attribute with value of type ".{0,N}"
private static final String STRING_LENGTH_PATTERN = ".{0,";
// Equivalent "codRegistro" values specified by "patterns" of type "0?NNNN"
private static final String EQUIVALENT_COD_REGISTRO_PATTERN = "0?";
// XML name for "codRegistro" attribute (indicates type of record)
private static final String COD_REGISTRO_XML_NAME = "codRegistro";
/**
* Write Castor object in file using fixed width records.
* @param castorObject File content
* @param file File for output
* @throws Exception
*/
public static void writeFile(Object castorObject, FileWriter file) throws Exception {
// Castor object validity
Method isValidMethod = castorObject.getClass().getMethod("isValid", new Class[]{});
Boolean valid = (Boolean)isValidMethod.invoke(castorObject, new Object[]{});
if (!valid) {
Method marshal = castorObject.getClass().getMethod("marshal", new Class[]{Writer.class});
marshal.invoke(castorObject, new Object[]{new StringWriter()});
}
// Write object into the file
writeFileInternal(castorObject, file);
file.endWrite();
}
/**
* Write Castor object in file using fixed width records.
* @param castorObject File content
* @param file File for output
* @throws Exception
*/
@SuppressWarnings("unchecked")
private static void writeFileInternal(Object castorObject, FileWriter file) throws Exception {
LineWriter lineWriter = new LineWriter();
// Castor object Descriptor
String className = castorObject.getClass().getPackage().getName() + ".descriptors." + castorObject.getClass().getSimpleName() + "Descriptor";
XMLClassDescriptorImpl descriptor = (XMLClassDescriptorImpl)Class.forName(className).newInstance();
// Elements holded by this Castor object
XMLFieldDescriptor[] fdList = (XMLFieldDescriptor[])descriptor.getFields();
for (XMLFieldDescriptor fd : fdList) {
// Complex element (simple and multiple elements)
if (fd.getValidator().getTypeValidator() == null) {
Method method = castorObject.getClass().getMethod("get" + fd.getXMLName(), new Class[]{});
Object retrievedCastorObject = method.invoke(castorObject, new Object[]{});
// Optional elements (minOccurs=0) should be not informed
if (retrievedCastorObject != null) {
if (retrievedCastorObject.getClass().isArray()) {
Object[] array = (Object[]) retrievedCastorObject;
for (Object element : array) {
writeFileInternal(element, file);
}
} else {
writeFileInternal(retrievedCastorObject, file);
}
}
// Simple element
} else {
Method method = castorObject.getClass().getMethod("get" + fd.getXMLName().substring(0,1).toUpperCase() + fd.getXMLName().substring(1), new Class[]{});
Object retrievedCastorObject = method.invoke(castorObject, new Object[]{});
// Only numeric and string fields processed
if (fd.getValidator().getTypeValidator() instanceof LongValidator) {
// Length fixed by "totalDigits" attribute
LongValidator lv = (LongValidator)fd.getValidator().getTypeValidator();
lineWriter.addNumber(retrievedCastorObject, lv.getTotalDigits());
} else {
// Length fixed by "pattern" attribute of type ".{0,N}"
StringValidator sv = (StringValidator)fd.getValidator().getTypeValidator();
List<string> patterns = sv.getPatterns();
for(String pattern : patterns) {
if (pattern.startsWith(STRING_LENGTH_PATTERN)) {
String maxLength = pattern.substring(STRING_LENGTH_PATTERN.length(), pattern.length() - 1);
lineWriter.addString(retrievedCastorObject, Integer.parseInt(maxLength));
}
}
}
}
}
if (lineWriter.getLine() != null && !"".equals(lineWriter.getLine())) {
file.writeNext(lineWriter.getLine());
}
}
/**
* Returns Castor object filled with data from the file.
* @param castorObject Initialized
* @param file Reading file
* @return Castor object containing file date
* @throws Exception
*/
public static Object readFile(Object castorObject, FileReader file) throws Exception {
Object retCastorObject = readFileInternal(castorObject, file, null, null, null, false);
file.endRead();
// Castor object validity
Method isValidMethod = retCastorObject.getClass().getMethod("isValid", new Class[]{});
Boolean valid = (Boolean)isValidMethod.invoke(retCastorObject, new Object[]{});
if (!valid) {
Method marshal = retCastorObject.getClass().getMethod("marshal", new Class[]{Writer.class});
marshal.invoke(retCastorObject, new Object[]{new StringWriter()});
}
return retCastorObject;
}
/**
* Equivalent codes are specified in XSD by "patterns" of type "0?NNNN"
*/
private static Map</string><string , List<Integer>> equivalentCodesMap = new HashMap</string><string , List<Integer>>();
private static Integer checkEquivalences(Integer codRegistro, Integer codRegistroPrevious) {
for (Map.Entry</string><string , List<Integer>> equivalentCodes : equivalentCodesMap.entrySet()) {
if (equivalentCodes.getValue().contains(codRegistro) && equivalentCodes.getValue().contains(codRegistroPrevious)) {
return codRegistro;
}
}
return codRegistroPrevious;
}
private static List</string><string> elementsInProcess = new ArrayList</string><string>();
/**
* Returns Castor object filled with data from the file.
* @param castorObject Object in use
* @param file Reading file
* @param lineReader Current line
* @param codRegistroPrevious "codRegistro" previously read
* @param parentCastorObject Parent object for object in use
* @param multiple Element multiple ("maxOccurs" specified in XSD)
* @return Castor object containing file date
* @throws Exception
*/
@SuppressWarnings("unchecked")
private static Object readFileInternal(
Object castorObject,
FileReader file,
LineReader lineReader,
Integer codRegistroPrevious,
Object parentCastorObject,
boolean multiple) throws Exception {
// Extract "codRegistro" from current line
Integer codRegistro = null;
if (lineReader == null || lineReader.isEnded()) {
lineReader = new LineReader(file.readNext());
codRegistro = lineReader.getInteger(5);
lineReader.reset();
} else if (lineReader.getCurrentPosition() == 0){
codRegistro = lineReader.getInteger(5);
lineReader.reset();
}
// Equivalent codes transformation
codRegistroPrevious = checkEquivalences(codRegistro, codRegistroPrevious);
// Elements in process (recurisivity control)
if (elementsInProcess.contains(castorObject.getClass().getSimpleName())) {
if (codRegistro == null && codRegistroPrevious == null) {
codRegistroPrevious = -1;
}
}
elementsInProcess.add(castorObject.getClass().getSimpleName());
// Process elements from reading file
if (codRegistroPrevious == null || (codRegistro != null && codRegistro.equals(codRegistroPrevious))) {
String targetMultipleMethod = null;
// Descriptor XML for current Castor object
XMLClassDescriptorImpl descriptor = null;
if (multiple && codRegistro != null && codRegistro.equals(codRegistroPrevious)) {
String className = parentCastorObject.getClass().getPackage().getName() + ".descriptors." + parentCastorObject.getClass().getSimpleName() + "Descriptor";
descriptor = (XMLClassDescriptorImpl)Class.forName(className).newInstance();
targetMultipleMethod = "add" + castorObject.getClass().getSimpleName();
castorObject = parentCastorObject;
} else {
String className = castorObject.getClass().getPackage().getName() + ".descriptors." + castorObject.getClass().getSimpleName() + "Descriptor";
descriptor = (XMLClassDescriptorImpl)Class.forName(className).newInstance();
}
// Elements contained in Castor object
XMLFieldDescriptor[] fdList = (XMLFieldDescriptor[])descriptor.getFields();
for (XMLFieldDescriptor fd : fdList) {
// Complex element (simple and multiple)
if (fd.getValidator().getTypeValidator() == null) {
Method[] methods = castorObject.getClass().getDeclaredMethods();
// Search "add" or "set" method to create new instance
for (Method method : methods) {
if (targetMultipleMethod == null || targetMultipleMethod.equals(method.getName())) {
if (method.getName().equals("add" + fd.getXMLName())) {
Class[] parameters = method.getParameterTypes();
Object[] values = new Object[parameters.length];
int i = 0;
for(Class parameter : parameters) {
values[i] = parameter.newInstance();
i++;
}
method.invoke(castorObject, values);
readFileInternal(values[0], file, lineReader, null, castorObject, true);
break;
} else if (method.getName().equals("set" + fd.getXMLName())) {
Class[] parameters = method.getParameterTypes();
Object[] values = new Object[parameters.length];
int i = 0;
for(Class parameter : parameters) {
values[i] = parameter.newInstance();
i++;
}
method.invoke(castorObject, values);
readFileInternal(values[0], file, lineReader, null, castorObject, false);
break;
}
}
}
// Simple element
} else {
// Detect equivalent codes
if (fd.getXMLName().equals(COD_REGISTRO_XML_NAME) && equivalentCodesMap.get(castorObject.getClass().getSimpleName()) == null) {
List<integer> equivalentCodes = new ArrayList</integer><integer>();
LongValidator lv = (LongValidator)fd.getValidator().getTypeValidator();
List<string> patterns = lv.getPatterns();
for(String pattern : patterns) {
if (pattern.startsWith(EQUIVALENT_COD_REGISTRO_PATTERN)) {
equivalentCodes.add(Integer.parseInt(pattern.substring(2)));
}
}
if (equivalentCodes.size() > 0) {
equivalentCodesMap.put(castorObject.getClass().getSimpleName(), equivalentCodes);
}
}
// Search "set" method to set the value
Method targetMethod = null;
Method[] methods = castorObject.getClass().getDeclaredMethods();
for(Method method : methods) {
if (method.getName().equals("set" + fd.getXMLName().substring(0,1).toUpperCase() + fd.getXMLName().substring(1))) {
targetMethod = method;
break;
}
}
try {
if (fd.getValidator().getTypeValidator() instanceof LongValidator) {
LongValidator lv = (LongValidator)fd.getValidator().getTypeValidator();
targetMethod.invoke(castorObject, new Object[]{lineReader.getLong(lv.getTotalDigits())});
} else {
StringValidator sv = (StringValidator)fd.getValidator().getTypeValidator();
List</string><string> patterns = sv.getPatterns();
for(String pattern : patterns) {
if (pattern.startsWith(STRING_LENGTH_PATTERN)) {
Integer maxLength = Integer.parseInt(pattern.substring(STRING_LENGTH_PATTERN.length(), pattern.length() - 1));
targetMethod.invoke(castorObject, new Object[]{lineReader.getString(maxLength)});
}
}
}
} catch (Exception e) {
// Skip current element
file.gotoPosition(file.getPreviousPosition());
// Remove current Castor object
if (multiple) {
String removeMethod = "remove" + castorObject.getClass().getSimpleName();
Method[] methodsParent = parentCastorObject.getClass().getDeclaredMethods();
for(Method method : methodsParent) {
if (method.getName().equals(removeMethod)) {
method.invoke(parentCastorObject, castorObject);
}
}
} else {
String removeMethod = "set" + castorObject.getClass().getSimpleName();
Method[] methodsParent = parentCastorObject.getClass().getDeclaredMethods();
for(Method method : methodsParent) {
if (method.getName().equals(removeMethod)) {
method.invoke(parentCastorObject, new Object[] {null});
}
}
}
multiple = false;
break;
}
}
}
// Search new instances
if (multiple) {
readFileInternal(castorObject, file, lineReader, codRegistro, parentCastorObject, true);
}
} else {
// Skip element
file.gotoPosition(file.getPreviousPosition());
}
// Clear empty objects
int getMethodsCount = 0;
int nullGetMethodsCount = 0;
boolean countMethodIsZero = false;
Method[] methods = castorObject.getClass().getDeclaredMethods();
for (Method method : methods) {
if (method.getName().startsWith("get") && method.getParameterTypes().length == 0) {
getMethodsCount++;
Object ret = method.invoke(castorObject);
if (ret == null) {
nullGetMethodsCount++;
} else if (ret.getClass().isArray()) {
Object[] o = (Object[]) ret;
if (o.length == 0) {
nullGetMethodsCount++;
}
} else if (ret instanceof Number) {
Number n = (Number) ret;
if (n.longValue() == 0) {
nullGetMethodsCount++;
countMethodIsZero = true;
}
}
}
}
// Simple node with element list
if (getMethodsCount == 2 && countMethodIsZero) {
nullGetMethodsCount = getMethodsCount;
}
if (nullGetMethodsCount == getMethodsCount) {
boolean removeMethodFound = false;
String removeMethod = "remove" + castorObject.getClass().getSimpleName();
Method[] methodsParent = parentCastorObject.getClass().getDeclaredMethods();
for(Method method : methodsParent) {
if (method.getName().equals(removeMethod)) {
method.invoke(parentCastorObject, castorObject);
removeMethodFound = true;
}
}
if (!removeMethodFound) {
removeMethod = "set" + castorObject.getClass().getSimpleName();
methodsParent = parentCastorObject.getClass().getDeclaredMethods();
for(Method method : methodsParent) {
if (method.getName().equals(removeMethod)) {
method.invoke(parentCastorObject, new Object[]{null});
}
}
}
}
elementsInProcess.remove(castorObject.getClass().getSimpleName());
return castorObject;
}
}
5. Sample read and write code
public class TestCDWRecResFile {
public static void main(String... args) throws Exception {
writeCDWRecResFile();
readCDWRecResFile();
}
private static Respuesta addRespuesta(String idSubTipoMensaje, String textoXML, int numLineasXML) {
Respuesta respuesta = new Respuesta();
CabeceraRespuesta cabeceraRespuesta = new CabeceraRespuesta();
cabeceraRespuesta.setIdTipoMensaje("RES");
cabeceraRespuesta.setIdSubTipoMensaje(idSubTipoMensaje);
cabeceraRespuesta.setIdSolicitud("1");
cabeceraRespuesta.setIdCartaCredito("1");
cabeceraRespuesta.setIdCliente("1");
cabeceraRespuesta.setFechaSolicitud("27032009");
respuesta.setCabeceraRespuesta(cabeceraRespuesta);
for(int i = 0; i < numLineasXML; i++) {
DetalleRespuesta detalleRespuesta = new DetalleRespuesta();
detalleRespuesta.setNumLinea((long)i + 1);
detalleRespuesta.setTextoXML(textoXML);
respuesta.addDetalleRespuesta(detalleRespuesta);
}
PieRespuesta pieRespuesta = new PieRespuesta();
pieRespuesta.setNumLineas((long)(1 + respuesta.getDetalleRespuestaCount() + 1));
pieRespuesta.setNumLineasXML((long)respuesta.getDetalleRespuestaCount());
respuesta.setPieRespuesta(pieRespuesta);
return respuesta;
}
public static void writeCDWRecResFile() throws Exception {
CDWRecResFile cdwRecResFile = new CDWRecResFile();
CabeceraFichero cabeceraFichero = new CabeceraFichero();
cabeceraFichero.setIdAplicacion("1");
cabeceraFichero.setFechaProceso("27032009");
cdwRecResFile.setCabeceraFichero(cabeceraFichero);
cdwRecResFile.addRespuesta(addRespuesta("ACP", "Cosa1", 2));
cdwRecResFile.addRespuesta(addRespuesta("REX", null, 0));
PieFichero pieFichero = new PieFichero();
pieFichero.setNumRespuestas((long)cdwRecResFile.getRespuestaCount());
long numRegistros = 2l; // cabecera fichero + pie fichero
Respuesta[] respuestas = cdwRecResFile.getRespuesta();
for(Respuesta r : respuestas) {
numRegistros = numRegistros + r.getPieRespuesta().getNumLineas();
}
pieFichero.setNumRegistros(numRegistros);
cdwRecResFile.setPieFichero(pieFichero);
FileWriter fw = new FileWriter("D:/apps/cdw/", "cdwrecres.txt");
BatchFile.writeFile(cdwRecResFile, fw);
}
public static void readCDWRecResFile() throws Exception {
FileReader file = new FileReader("D:/apps/cdw/", "cdwrecres.txt");
CDWRecResFile cdwRecResFile = new CDWRecResFile();
cdwRecResFile = (CDWRecResFile)BatchFile.readFile(cdwRecResFile, file);
StringWriter sw = new StringWriter();
cdwRecResFile.marshal(sw);
System.out.println(sw.toString());
}
As it can be seen, maintenance operations can be performed clearly on XSD file and the impact on Java code (sample on point 5) is reduced and can be controlled.
Some conventions have been asumed to develop this code:
- codRegistro field indicates the type of record
- Multiple elements can be repeated only if codRegistro field is the same for each line
- Some Castor limitations provide a limited type XSD definition (p.e. the use of “pattern” restriction in String instead of “length”)
ThreadLocal considerations. Use in WebSphere 6 and Weblogic 10.
ThreadLocal class enables the sharing of a variable in a statically way across a whole Java process by attaching this variable to a single Thread (p.e. Thread.currentThread()). This is specially useful to make accesible values recovered in filter layer to the other ones.
Think about database logging of HTTP requests or responses. Note that this is the unique point to retrieve, for instance, complete signed requests or responses. All this process (request and response) is executed on a single thread, so ThreadLocal mechanism can be used to share the request content with the DAO layer. By doing a threadLocal.set(request) on Filter class and a threadLocal.get() on DAO class the described functionality is achieved.
And here is where different behaviours arrive. WebSphere 6 doesn’t clean servlet pooled threads after execution while Weblogic 10 does. So, ThreadLocal variable must be cleared in WebSphere for every new request!
Typically is discouraged the use of this tecnique in managed environments, but in many cases the best should be the simpliest.
Reference - IBM – Threading lightly.
Dump request and response using javax.servlet.Filter
Java class
package com.foo;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.CharArrayWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
public class DumpFilter implements Filter {
private static class ByteArrayServletStream extends ServletOutputStream {
ByteArrayOutputStream baos;
ByteArrayServletStream(ByteArrayOutputStream baos) {
this.baos = baos;
}
public void write(int param) throws IOException {
baos.write(param);
}
}
private static class ByteArrayPrintWriter {
private ByteArrayOutputStream baos = new ByteArrayOutputStream();
private PrintWriter pw = new PrintWriter(baos);
private ServletOutputStream sos = new ByteArrayServletStream(baos);
public PrintWriter getWriter() {
return pw;
}
public ServletOutputStream getStream() {
return sos;
}
byte[] toByteArray() {
return baos.toByteArray();
}
}
private class BufferedServletInputStream extends ServletInputStream {
ByteArrayInputStream bais;
public BufferedServletInputStream(ByteArrayInputStream bais) {
this.bais = bais;
}
public int available() {
return bais.available();
}
public int read() {
return bais.read();
}
public int read(byte[] buf, int off, int len) {
return bais.read(buf, off, len);
}
}
private class BufferedRequestWrapper extends HttpServletRequestWrapper {
ByteArrayInputStream bais;
ByteArrayOutputStream baos;
BufferedServletInputStream bsis;
byte[] buffer;
public BufferedRequestWrapper(HttpServletRequest req) throws IOException {
super(req);
InputStream is = req.getInputStream();
baos = new ByteArrayOutputStream();
byte buf[] = new byte[1024];
int letti;
while ((letti = is.read(buf)) > 0) {
baos.write(buf, 0, letti);
}
buffer = baos.toByteArray();
}
public ServletInputStream getInputStream() {
try {
bais = new ByteArrayInputStream(buffer);
bsis = new BufferedServletInputStream(bais);
} catch (Exception ex) {
ex.printStackTrace();
}
return bsis;
}
public byte[] getBuffer() {
return buffer;
}
}
private boolean dumpRequest;
private boolean dumpResponse;
public void init(FilterConfig filterConfig) throws ServletException {
dumpRequest = Boolean.valueOf(filterConfig.getInitParameter("dumpRequest"));
dumpResponse = Boolean.valueOf(filterConfig.getInitParameter("dumpResponse"));
}
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,
FilterChain filterChain) throws IOException, ServletException {
final HttpServletRequest httpRequest = (HttpServletRequest)servletRequest;
BufferedRequestWrapper bufferedRequest= new BufferedRequestWrapper(httpRequest);
if (dumpRequest) {
System.out.println("REQUEST -> " + new String(bufferedRequest.getBuffer());
}
final HttpServletResponse response = (HttpServletResponse) servletResponse;
final ByteArrayPrintWriter pw = new ByteArrayPrintWriter();
HttpServletResponse wrappedResp = new HttpServletResponseWrapper(response) {
public PrintWriter getWriter() {
return pw.getWriter();
}
public ServletOutputStream getOutputStream() {
return pw.getStream();
}
};
filterChain.doFilter(bufferedRequest, wrappedResp);
byte[] bytes = pw.toByteArray();
response.getOutputStream().write(bytes);
if (dumpResponse) System.out.println("RESPONSE -> " + new String(bytes));
}
public void destroy() {}
}
web.xml
<filter>
<filter_name>DumpFilter</filter_name>
<filter_class>
com.foo.DumpFilter
</filter_class>
<init_param>
<param_name>dumpRequest</param_name>
<param_value>true</param_value>
</init_param>
<init_param>
<param_name>dumpResponse</param_name>
<param_value>true</param_value>
</init_param>
</filter>
<filter_mapping>
<filter_name>DumpFilter</filter_name>
<url_pattern>/services/*</url_pattern>
</filter_mapping>
Note. Character “-” replaced by “_” in web.xml for correct visualization.
