NetBeans_021：开发JavaEE 7 应用之四：使用Batch计算售票总金额

开发运行环境：NetBeans7.3.1。

关于Batch 1.0，请参考《JavaEE7 十大新特性》。

1. SalesReader.java
SalesReader.java是ItemReader，每次读取sales.csv的一行数据。

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package org.glassfish.movieplex7.batch;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Serializable;
import javax.batch.api.chunk.AbstractItemReader;
import javax.enterprise.context.Dependent;
import javax.inject.Named;

/**
 *
 * @author pmma
 */
@Named
@Dependent
public class SalesReader extends AbstractItemReader {

    private BufferedReader reader;

    @Override
    public void open(Serializable checkpoint) throws Exception {
        reader = new BufferedReader(
                new InputStreamReader(
                Thread.currentThread()
                .getContextClassLoader()
                .getResourceAsStream("META-INF/sales.csv")));
    }

    @Override
    public String readItem() {
        String string = null;
        try {
            string = reader.readLine();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        return string;
    }
}

2. SalesProcessor.java
SalesProcessor.java是ItemProcessor，每次分析读取SalesReader提供的Item数据，即读取的sales.csv的一行数据，把电影id和金额信息保存到Sales Entity中。

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package org.glassfish.movieplex7.batch;

import java.util.StringTokenizer;
import javax.batch.api.chunk.ItemProcessor;
import javax.enterprise.context.Dependent;
import javax.inject.Named;
import org.glassfish.movieplex7.entities.Sales;

/**
 *
 * @author pmma
 */
@Named
@Dependent
public class SalesProcessor implements ItemProcessor {

    @Override
    public Sales processItem(Object s) {
        Sales sales = new Sales();
        StringTokenizer tokens = new StringTokenizer((String) s, ",");
        sales.setId(Integer.parseInt(tokens.nextToken()));
        sales.setAmount(Float.parseFloat(tokens.nextToken()));
        return sales;
    }
}

3. SalesWriter.java

SalesWriter.java是ItemWriter，批量提交多个每次分析读取SalesProcessor提供的Item数据，即把多个Sales Entities一次提交到数据库中。

/*

 * To change this template, choose Tools | Templates

 * and open the template in the editor.

 */

package org.glassfish.movieplex7.batch;

import java.util.List;

import javax.batch.api.chunk.AbstractItemWriter;

import javax.enterprise.context.Dependent;

import javax.inject.Named;

import javax.persistence.EntityManager;

import javax.persistence.PersistenceContext;

import javax.transaction.Transactional;

import org.glassfish.movieplex7.entities.Sales;

/**

 *

 * @author pmma

 */

@Named

@Dependent

public class SalesWriter extends AbstractItemWriter {

    @PersistenceContext

    EntityManager em;

    @Override

    @Transactional

    public void writeItems(List list) {

        for (Sales s : (List) list) {

            em.persist(s);

        }

    }

}

说明：

（1）在writeItems上有 @Transactional批注，说明该方法是带事务的，这是JPA 2.1的新特性，即支持在任意一个POJO类上加事务。

4. Job XML配置文件：eod-sales.xml
<job id="endOfDaySales" xmlns="http://xmlns.jcp.org/xml/ns/javaee"

     version="1.0">

    <step id="populateSales">

        <chunk item-count="3" skip-limit="5">

            <reader ref="salesReader"/>

            <processor ref="salesProcessor"/>

            <writer ref="salesWriter"/>

            <skippable-exception-classes>

                <include class="java.lang.NumberFormatException"/>

            </skippable-exception-classes>

        </chunk>

    </step>

</job>

说明：

（1）endOfDaySales Job有一个Step，该Step有一个Chunk。

（2）在Chunk中，item-count="3"，在这里表明一次处理3行销售数据。

（3）skippable-exception-classes：java.lang.NumberFormatException表明忽略该异常。

（4）skip-limit="5"，表明最多忽略5次异常。

5. SalesBean.java
SalesBean.java是一个Managed Bean，负责启动Job，其中使用了JobOperator。

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package org.glassfish.movieplex7.batch;

import java.util.List;
import java.util.Properties;
import javax.batch.operations.JobOperator;
import javax.batch.operations.JobStartException;
import javax.batch.runtime.BatchRuntime;
import javax.enterprise.context.RequestScoped;
import javax.inject.Named;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import org.glassfish.movieplex7.entities.Sales;

/**
 *
 * @author pmma
 */
@Named
@RequestScoped
public class SalesBean {

    @PersistenceUnit
    EntityManagerFactory emf;

    public void runJob() {
        try {
            JobOperator jo = BatchRuntime.getJobOperator();
            long jobId = jo.start("eod-sales", new Properties());
            System.out.println("Started job: with id: " + jobId);
        } catch (JobStartException ex) {
            ex.printStackTrace();
        }
    }

    public List getSalesData() {
        return emf.createEntityManager().createNamedQuery("Sales.findAll",
                Sales.class).getResultList();
    }

}

6. sales.xhtml
Table绑定#{salesBean.salesData}，用于显示电影售票情况；按钮绑定#{salesBean.runJob()}，点击启动Job。

<?xml version='1.0' encoding='UTF-8' ?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml"

      xmlns:ui="http://xmlns.jcp.org/jsf/facelets"

      xmlns:h="http://xmlns.jcp.org/jsf/html"

      xmlns:f="http://xmlns.jcp.org/jsf/core">

    <body>

        <ui:composition template="./../WEB-INF/template.xhtml">

            <ui:define name="content">

                <h1>Movie Sales</h1>

                <h:form>

                    <h:dataTable value="#{salesBean.salesData}" var="s" border="1">

                        <h:column>

                            <f:facet name="header">

                                <h:outputText value="Show ID" />

                            </f:facet>

                            #{s.id}

                        </h:column>

                        <h:column>

                            <f:facet name="header">

                                <h:outputText value="Sales" />

                            </f:facet>

                            #{s.amount}

                        </h:column>

                    </h:dataTable>

                    <h:commandButton value="Run Job" action="sales"

                                     actionListener="#{salesBean.runJob()}"/>

                    <h:commandButton value="Refresh" action="sales" />

                </h:form>

            </ui:define>

        </ui:composition>

    </body>

</html>

Project 下载：5.movieplex7(Batch).7z