来自Spring批处理Jaxb2Marshaller-Marshall.JAXB_FORMACTED_OUTPUT的XML输出不起作用，为什么？

问题描述

我正在进行将MongoDB转换为XML的Spring批处理。我有以下两个代码片段。

首先：

<bean id="reportMarshaller" class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
    <property name="classesToBeBound">
        <value>com.mkyong.model.Report</value>
    </property>
    <property name="marshallerProperties">
        <map>
            <entry>
                <key>
                    <util:constant static-field="javax.xml.bind.Marshaller.JAXB_FORMATTED_OUTPUT"/>
                </key>
                <value type="boolean">true</value>
            </entry>
        </map>
    </property>
</bean>

第二个

<bean id="reportMarshaller" class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
    <property name="classesToBeBound">
        <value>com.mkyong.model.Report</value>
    </property>
</bean>

两种配置都没有格式化输出文件。结果只打印在一行XML文件中。我原以为第一个配置将格式化结果，但事实并非如此。

我在单行XML文件中看到的输出：

pom.xml

<properties>
    <!-- Generic properties -->
    <java.version>1.7</java.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

    <spring.version>4.3.5.RELEASE</spring.version>
    <spring.batch.version>3.0.7.RELEASE</spring.batch.version>
    <spring.data.version>1.8.4.RELEASE</spring.data.version>
    <mongodb.driver.version>3.1.1</mongodb.driver.version>

    <!-- Logging -->
    <logback.version>1.0.13</logback.version>
    <slf4j.version>1.7.5</slf4j.version>
    <jcl.slf4j.version>1.7.12</jcl.slf4j.version>

    <!-- Test -->
    <junit.version>4.12</junit.version>

</properties>

<dependencies>
    <!-- Spring Core -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${spring.version}</version>
    </dependency>

    <!-- Spring XML to/back object -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-oxm</artifactId>
        <version>${spring.version}</version>
    </dependency>

    <!-- Spring Batch dependencies -->
    <dependency>
        <groupId>org.springframework.batch</groupId>
        <artifactId>spring-batch-core</artifactId>
        <version>${spring.batch.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.batch</groupId>
        <artifactId>spring-batch-infrastructure</artifactId>
        <version>${spring.batch.version}</version>
    </dependency>

    <!-- Spring Batch unit test -->
    <dependency>
        <groupId>org.springframework.batch</groupId>
        <artifactId>spring-batch-test</artifactId>
        <version>${spring.batch.version}</version>
    </dependency>

    <!-- MongoDB database driver -->
    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>mongo-java-driver</artifactId>
        <version>${mongodb.driver.version}</version>
    </dependency>

    <!-- Logging with SLF4J & LogBack -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${slf4j.version}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>${logback.version}</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>jcl-over-slf4j</artifactId>
        <version>${jcl.slf4j.version}</version>
    </dependency>

    <!-- Spring data mongodb -->
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-mongodb</artifactId>
        <version>${spring.data.version}</version>
    </dependency>

    <dependency>
        <groupId>javax.xml.bind</groupId>
        <artifactId>jaxb-api</artifactId>
        <version>2.2.12</version>
    </dependency>


    <!-- Junit -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
        <scope>test</scope>
    </dependency>

    <!-- Testng -->
    <dependency>
        <groupId>org.testng</groupId>
        <artifactId>testng</artifactId>
        <version>6.8.5</version>
        <scope>test</scope>
    </dependency>
</dependencies>

我正在使用以下内容：

<bean id="xmlItemWriter" class="org.springframework.batch.item.xml.StaxEventItemWriter">
    <property name="resource" value="file:outputs/report.xml" />
    <property name="encoding" value="ISO-8859-1" />
    <property name="version" value="1.0" />
    <property name="marshaller" ref="reportMarshaller" />
    <property name="rootTagName" value="record" />
    <!-- TRUE means, that output file will be overwritten if exists - default is TRUE -->
    <property name="overwriteOutput" value="true" />
</bean>

根据Karthik的输入：

<?xml version="1.0" encoding="ISO-8859-1"?>
<record><record id="1">
    <date>01-06-2013</date>
    <impression>139237</impression>
    <clicks>40</clicks>
    <earning>220.90</earning>
  </record><record id="2">
    <date>02-06-2013</date>
    <impression>339100</impression>
    <clicks>60</clicks>
    <earning>320.88</earning>
  </record><record id="3">
    <date>03-06-2013</date>
    <impression>431436</impression>
    <clicks>76</clicks>
    <earning>270.80</earning>
  </record><record id="4">
    <date>12-03-2016</date>
    <impression>534987</impression>
    <clicks>43</clicks>
    <earning>454.80</earning>
  </record></record>

推荐答案

看这个JIRA Ticket，这个问题在春批中还没有修复。但是，有解决此问题的方法。

添加maven依赖项。

<dependency>
    <groupId>net.java.dev.stax-utils</groupId>
    <artifactId>stax-utils</artifactId>
    <version>20070216</version>
</dependency>

创建自定义类。

public class IndentingStaxEventItemWriter <T> extends StaxEventItemWriter<T> {

      private boolean indenting = true;

      @Override
      protected XMLEventWriter createXmlEventWriter( XMLOutputFactory outputFactory, Writer writer) throws XMLStreamException {
        if (indenting) {
          return new IndentingXMLEventWriter( super.createXmlEventWriter( outputFactory, writer ) );
        }
        else {
          return super.createXmlEventWriter( outputFactory, writer );
        }
      }

    public boolean isIndenting() {
        return indenting;
    }

    public void setIndenting(boolean indenting) {
        this.indenting = indenting;
    }

}

修改您的EventWriter

<bean id="xmlItemWriter" class="com.kp.IndentingStaxEventItemWriter">
    <property name="resource" value="file:outputs/report.xml" />
    <property name="encoding" value="ISO-8859-1" />
    <property name="version" value="1.0" />
    <property name="marshaller" ref="reportMarshaller" />
    <property name="rootTagName" value="record" />
    <!-- TRUE means, that output file will be overwritten if exists - default is TRUE -->
    <property name="overwriteOutput" value="true" />
</bean>