这是我的方法：
@Autowired
private HeadHunterService headHunterService;
public String getBarChartUrlByLang(String pl) {
List<HeadHunter> headHunter = headHunterService.getLastDataByLang(pl);
List<String> city = new ArrayList<String>();
List<Integer> salaries = new ArrayList<Integer>();
for (int i = 0; i < headHunter.size(); i++) {
city.add(headHunter.get(i).getCity().toString());
salaries.add(headHunter.get(i).getSalary().intValue());
}
final int MAX_SALARY = headHunter.get(0).getSalary();
Data salaryData = DataUtil.scaleWithinRange(0, MAX_SALARY, salaries);
BarChartPlot salary = Plots.newBarChartPlot(salaryData,
Color.newColor("3298C9"));
BarChart chart = GCharts.newBarChart(salary);
// Defining axis info and styles
AxisStyle axisStyle = AxisStyle.newAxisStyle(Color.newColor("000000"),
9, AxisTextAlignment.CENTER);
AxisLabels cities = AxisLabelsFactory.newAxisLabels(city);
cities.setAxisStyle(axisStyle);
AxisLabels salaryCount = AxisLabelsFactory.newNumericRangeAxisLabels(0,
MAX_SALARY);
salaryCount.setAxisStyle(axisStyle);
// Adding axis info to chart.
chart.addXAxisLabels(cities);
chart.addYAxisLabels(salaryCount);
chart.setHorizontal(false);
chart.setSize(800, 300);
chart.setSpaceBetweenGroupsOfBars(54);
// /51 is the max number of medals.
chart.setGrid(10, 800, 3, 2);
chart.setBackgroundFill(Fills.newSolidFill(Color.newColor("FFFFFF")));
String url = chart.toURLString();
return url;
}
这就是我 xml 的方式：
<bean id="googleCharts" class="net.babobka.blog.charts.GoogleCharts" />
如果我在控制器中调用它，它会正常工作。但现在我正在尝试调用另一个名为PDFBuilder. 这就是我所拥有的：
java.lang.NullPointerException
at net.babobka.blog.pdf.PDFBuilder.buildPdfDocument(PDFBuilder.java:47)
at net.babobka.blog.pdf.AbstractITextPdfView.renderMergedOutputModel(AbstractITextPdfView.java:47)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1180)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:950)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
第47行是：System.out.println(googleCharts.getBarChartUrlByLang("Java"));
这是我的根上下文：
<context:annotation-config />
<context:component-scan base-package="net.babobka.blog" />
<mvc:resources mapping="/resources/**" location="/resources/" />
<cache:annotation-driven />
<bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager">
<property name="caches">
<set>
<bean
class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean"
p:name="template" />
<bean
class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean"
p:name="headHunter" />
</set>
</property>
</bean>
<bean id="converter" class="net.babobka.blog.headHunter.Converter" />
<bean id="googleCharts" class="net.babobka.blog.charts.GoogleCharts" />
<bean id="propertyConfigurer"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
p:location="/WEB-INF/db/jdbc.properties" />
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close" p:driverClassName="${jdbc.driverClassName}"
p:url="${jdbc.databaseurl}" p:username="${jdbc.username}" p:password="${jdbc.password}" />
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation">
<value>/WEB-INF/db/hibernate.cfg.xml</value>
</property>
<property name="configurationClass">
<value>org.hibernate.cfg.AnnotationConfiguration</value>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${jdbc.dialect}</prop>
<prop key="hibernate.show_sql">${jdbc.show_sql}</prop>
<prop key="hibernate.connection.useUnicode">true</prop>
<prop key="hibernate.connection.characterEncoding">UTF-8</prop>
<prop key="hibernate.connection.charSet">UTF-8</prop>
</props>
</property>
</bean>
<bean id="transactionManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<mvc:annotation-driven />
<tx:annotation-driven />
<task:annotation-driven />
<bean id="Backupper" class="net.babobka.blog.backupper.Backupper"></bean>
<bean id="OldDataRemoval" class="net.babobka.blog.termination.OldDataRemoval"></bean>
<bean id="HeadHunterImport" class="net.babobka.blog.headHunter.HeadHunterImport"></bean>
<bean id="urlForwardController"
class="org.springframework.web.servlet.mvc.UrlFilenameViewController" />
<bean id="tilesConfigurer"
class="org.springframework.web.servlet.view.tiles2.TilesConfigurer">
<property name="definitions">
<list>
<value>/WEB-INF/tiles.xml</value>
</list>
</property>
</bean>
<bean id="viewResolver"
class="org.springframework.web.servlet.view.UrlBasedViewResolver">
<property name="viewClass"
value="org.springframework.web.servlet.view.tiles2.TilesView" />
</bean>
<bean id="viewResolver1"
class="org.springframework.web.servlet.view.ResourceBundleViewResolver">
<property name="order" value="1" />
<property name="basename" value="views" />
</bean>
和 PDFBuilder（我不认为它有帮助）：
public class PDFBuilder extends AbstractITextPdfView {
@Autowired
private GoogleCharts googleCharts;
@Override
protected void buildPdfDocument(Map<String, Object> model, Document doc,
PdfWriter writer, HttpServletRequest request,
HttpServletResponse response) throws Exception {
// get data model which is passed by the Spring container
List<HeadHunter> listHeadHunter = (List<HeadHunter>) model
.get("listHeadHunter");
doc.add(new Paragraph("Last data for "
+ listHeadHunter.get(0).getPl().toString()));
System.out.println(googleCharts.getBarChartUrlByLang("C++"));
String imageUrl = "http://chart.apis.google.com/chart?cht=bvg&chxt=y,x&chco=3298C9&chs=800x300&chbh=23,4,54&chf=bg,s,FFFFFF&chg=10.0,800.0,3,2&chxr=0,0.0,91557.0&chd=e:..0wx1t6tbrBpCkhjOi4&chxs=0,000000,9,0|1,000000,9,0&chxl=1:|Moscow|Saint+Petersburg|Voronezh|Nizhny+Novgorod|Tomsk|Novosibirsk|Yekaterinburg|Samara|Kazan|Rostov-on-Don";
PdfPTable table = new PdfPTable(3);
table.setWidthPercentage(100.0f);
table.setWidths(new float[] { 3.0f, 2.0f, 2.0f });
table.setSpacingBefore(10);
// define font for table header row
Font font = FontFactory.getFont(FontFactory.HELVETICA);
font.setColor(BaseColor.WHITE);
// define table header cell
PdfPCell cell = new PdfPCell();
BaseColor color = new BaseColor(50, 152, 186);
cell.setBackgroundColor(color);
cell.setPadding(10);
// write table header
cell.setPhrase(new Phrase("City", font));
table.addCell(cell);
cell.setPhrase(new Phrase("Vacancies", font));
table.addCell(cell);
cell.setPhrase(new Phrase("Avg. salary", font));
table.addCell(cell);
// write table row data
for (HeadHunter hh : listHeadHunter) {
table.addCell(hh.getCity());
table.addCell(hh.getVacancies().toString());
table.addCell(hh.getSalary().toString());
}
doc.add(table);
doc.add(new Paragraph("\n Visual representation (salary/city)"));
Image image = Image.getInstance(new URL(imageUrl));
image.setAbsolutePosition(35f, 335f);
image.scaleAbsolute(540f, 203f);
doc.add(image);
}
}
怎么了？