[SalesForce] How to Display Integer value got from SOQL Query (Apex Class) to Visualforce Page

You can use the action attribute of the page tag for this - that will execute an action method on the controller before anything is rendered. E.g.

Controller:

public class MyController
{
   public void MyActionMethod()
   {
      // do some stuff here
   }
}

Page:

<apex:page controller="MyController" action="{!MyActionMethod}">

<!-- rest of page -->

</page>

One important point to note - this should not be used to initialise information that other parts of the page rely on, as there is no guarantee that this method will be called before the getters (my understanding is that is how it currently works, but may change in the future) - there's a thread with one of the Visualforce developer's explaining this in more detail at:

https://developer.salesforce.com/forums?id=906F0000000957bIAA

If this causes a problem, the other way is to execute some JavaScript when the page loads that invokes the action method and then renders the rest of the page. I've blogged that solution at:

http://bobbuzzard.blogspot.co.uk/2011/08/dml-during-initialisation.html

I do not see examples of exactly what you want in documentation such as Building a Complex Chart with Visualforce Charting.

But you should be able to get part of the way there because apex:barSeries supports colorSet and colorsProgressWithinSeries attributes. It looks like putting the colors there using a true value should give a different color per bar.

In the examples I have seen, the apex:legend is typically used to describe the series and you only have one series (your apex:barSeries). You are trying to get the legend to repeat the labels of the x-axis and that does not appear to be a supported option.

So I suggest the compromise of using the colored bars and just removing the legend.

PS

The code below produces the chart below and demonstrates that just setting colorsProgressWithinSeries allows the colors from the apex:chart to be used. When experimenting with the size of the chart, I found that the legends are hidden when they don't fit so making the chart bigger is the simplest way to get all the legends shown. One purpose of the legend when displayed is to turn a series on and off so the legend has little value when there is only one series. And there appears to be no option to repurpose the legend to show axis values instead so I think your are out of luck. (Or if the first chart you show was created using apex:chart contact whoever created it and ask them.)

<apex:page controller="ChartController">
    <apex:pageBlock title="Annual Recurring Revenue">
        <apex:chart name="AnnualRecurringRevenue" data="{!nvs}" width="400" height="400"
                colorSet="#156F9E,#FF9123,#6BAE4A,#424242,#A4A4A4">
            <apex:axis type="Numeric" position="left" grid="true" title="$(Millions)"
                    fields="v"/>
            <apex:axis type="Category" position="bottom" grid="false" title="Quarter"
                    fields="n"/>
            <apex:barSeries orientation="vertical" axis="left" xField="n" yField="v"
                    colorsProgressWithinSeries="true"/>
        </apex:chart>
    </apex:pageBlock>
</apex:page>

public class ChartController {
    public class Nv {
        public String n { get; private set; }        
        public Decimal v { get; private set; }
        Nv(String n, Decimal v) {
            this.n = n;
            this.v = v;       
        }
    }
    public Nv[] getNvs() {
        return new Nv[] {
            new Nv('Actual', 106.00),
            new Nv('Forecast', 150.56),
            new Nv('Plan', 135.00),
            new Nv('Prior Qtr', 97.00),
            new Nv('Prior Yr', 88.44)
        };
    }
}