blocks|key|61909|text|您可以通过在ObjectMapper上设置SerializationFeature.INDENT_OUTPUT来启用美观打印，如下所示：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|61910|mapper.enable(SerializationFeature.INDENT_OUTPUT);|code-block|syntax|javascript|61911|entityMap^0|6|C|L|Y|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

You can enable pretty-printing by setting the <code>SerializationFeature.INDENT_OUTPUT</code> on your <code>ObjectMapper</code> like so:

<pre><code>mapper.enable(SerializationFeature.INDENT_OUTPUT);
</code></pre>

blocks|key|62036|text|jackson+API已更改：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|62037|new+ObjectMapper()
.writer()
.withDefaultPrettyPrinter()
.writeValueAsString(new+HashMap<String,+Object>());|code-block|syntax|javascript|62038|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The jackson API has changed:

<pre><code>new ObjectMapper()
.writer()
.withDefaultPrettyPrinter()
.writeValueAsString(new HashMap&lt;String, Object&gt;());
</code></pre>

blocks|key|61962|text|IDENT_OUTPUT没有为我做任何事情，并且给出了一个与我的jackson+2.2.3+jars一起工作的完整答案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|61963|public+static+void+main(String[]+args)+throws+IOException+{

byte[]+jsonBytes+=+Files.readAllBytes(Paths.get("C:\\data\\testfiles\\single-line.json"));

ObjectMapper+objectMapper+=+new+ObjectMapper();

Object+json+=+objectMapper.readValue(+jsonBytes,+Object.class+);

System.out.println(+objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(+json+)+);
}|code-block|syntax|javascript|61964|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

the IDENT_OUTPUT did not do anything for me, and to give a complete answer that works with my jackson 2.2.3 jars:

<pre><code>public static void main(String[] args) throws IOException {

byte[] jsonBytes = Files.readAllBytes(Paths.get("C:\\data\\testfiles\\single-line.json"));

ObjectMapper objectMapper = new ObjectMapper();

Object json = objectMapper.readValue( jsonBytes, Object.class );

System.out.println( objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString( json ) );
}
</code></pre>

blocks|key|278332|text|如果您想在默认情况下为进程中的所有ObjectMapper实例打开此功能，这里有一个小技巧，它会将INDENT_OUTPUT的默认值设置为true：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|278333|val+indentOutput+=+SerializationFeature.INDENT_OUTPUT
val+defaultStateField+=+indentOutput.getClass.getDeclaredField("_defaultState")
defaultStateField.setAccessible(true)
defaultStateField.set(indentOutput,+true)|code-block|syntax|javascript|278334|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you'd like to turn this on by default for ALL ObjectMapper instances in a process, here's a little hack that will set the default value of INDENT_OUTPUT to true:

<pre><code>val indentOutput = SerializationFeature.INDENT_OUTPUT
val defaultStateField = indentOutput.getClass.getDeclaredField("_defaultState")
defaultStateField.setAccessible(true)
defaultStateField.set(indentOutput, true)
</code></pre>

blocks|key|62075|text|如果你使用的是spring和jackson的组合，你可以这样做。我按照建议遵循了@gregwhitaker，但以spring风格实现。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|62076|<bean+id="objectMapper"+class="com.fasterxml.jackson.databind.ObjectMapper">
++++<property+name="dateFormat">
++++++++<bean+class="java.text.SimpleDateFormat">
++++++++++++<constructor-arg+value="yyyy-MM-dd"+/>
++++++++++++<property+name="lenient"+value="false"+/>
++++++++</bean>
++++</property>
++++<property+name="serializationInclusion">
++++++++<value+type="com.fasterxml.jackson.annotation.JsonInclude.Include">
++++++++++++NON_NULL
++++++++</value>
++++</property>
</bean>

<bean+class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
++++<property+name="targetObject">
++++++++<ref+bean="objectMapper"+/>
++++</property>
++++<property+name="targetMethod">
++++++++<value>enable</value>
++++</property>
++++<property+name="arguments">
++++++++<value+type="com.fasterxml.jackson.databind.SerializationFeature">
++++++++++++INDENT_OUTPUT
++++++++</value>
++++</property>
</bean>|code-block|syntax|javascript|62077|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

if you are using spring and jackson combination you can do it as following. I'm following @gregwhitaker as suggested but implementing in spring style.


 
 

<pre><code>&lt;bean id="objectMapper" class="com.fasterxml.jackson.databind.ObjectMapper"&gt;
 &lt;property name="dateFormat"&gt;
 &lt;bean class="java.text.SimpleDateFormat"&gt;
 &lt;constructor-arg value="yyyy-MM-dd" /&gt;
 &lt;property name="lenient" value="false" /&gt;
 &lt;/bean&gt;
 &lt;/property&gt;
 &lt;property name="serializationInclusion"&gt;
 &lt;value type="com.fasterxml.jackson.annotation.JsonInclude.Include"&gt;
 NON_NULL
 &lt;/value&gt;
 &lt;/property&gt;
&lt;/bean&gt;

&lt;bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean"&gt;
 &lt;property name="targetObject"&gt;
 &lt;ref bean="objectMapper" /&gt;
 &lt;/property&gt;
 &lt;property name="targetMethod"&gt;
 &lt;value&gt;enable&lt;/value&gt;
 &lt;/property&gt;
 &lt;property name="arguments"&gt;
 &lt;value type="com.fasterxml.jackson.databind.SerializationFeature"&gt;
 INDENT_OUTPUT
 &lt;/value&gt;
 &lt;/property&gt;
&lt;/bean&gt;
</code></pre>

blocks|key|62098|text|如果其他查看此问题的人只有一个JSON字符串(不在对象中)，那么您可以将其放入HashMap中，并且仍然可以让ObjectMapper工作。result变量是您的JSON字符串。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|62099|import+com.fasterxml.jackson.core.JsonParseException;
import+com.fasterxml.jackson.databind.JsonMappingException;
import+com.fasterxml.jackson.databind.ObjectMapper;
import+java.util.HashMap;
import+java.util.Map;

//+Pretty-print+the+JSON+result
try+{
++++ObjectMapper+objectMapper+=+new+ObjectMapper();
++++Map<String,+Object>+response+=+objectMapper.readValue(result,+HashMap.class);
++++System.out.println(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(response));
}+catch+(JsonParseException+e)+{
++++e.printStackTrace();
}+catch+(JsonMappingException+e)+{
++++e.printStackTrace();
}+catch+(IOException+e)+{
++++e.printStackTrace();
}+|code-block|syntax|javascript|62100|entityMap^0|13|7|1J|C|1Y|6|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|L|$]]

If others who view this question only have a JSON string (not in an object), then you can put it into a <code>HashMap</code> and still get the <code>ObjectMapper</code> to work. The <code>result</code> variable is your JSON string.

<pre><code>import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.HashMap;
import java.util.Map;

// Pretty-print the JSON result
try {
 ObjectMapper objectMapper = new ObjectMapper();
 Map&lt;String, Object&gt; response = objectMapper.readValue(result, HashMap.class);
 System.out.println(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(response));
} catch (JsonParseException e) {
 e.printStackTrace();
} catch (JsonMappingException e) {
 e.printStackTrace();
} catch (IOException e) {
 e.printStackTrace();
} 
</code></pre>

blocks|key|61930|text|尝尝这个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|61931|+objectMapper.enable(SerializationConfig.Feature.INDENT_OUTPUT);|code-block|syntax|javascript|61932|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this.

<pre><code> objectMapper.enable(SerializationConfig.Feature.INDENT_OUTPUT);
</code></pre>

Right now I have an instance of <code>org.fasterxml.jackson.databind.ObjectMapper</code> and would like to get a <code>String</code> with pretty JSON. All of the results of my Google searches have come up with Jackson 1.x ways of doing this and I can't seem to find the proper, non-deprecated way of doing this with 2.2. Even though I don't believe that code is absolutely necessary for this question, here's what I have right now:

<pre><code>ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(Include.NON_NULL);
System.out.println("\n\n----------REQUEST-----------");
StringWriter sw = new StringWriter();
mapper.writeValue(sw, jsonObject);
// Want pretty version of sw.toString() here
</code></pre>

Pretty printing JSON from Jackson 2.2's ObjectMapper

JSON

现在，我有一个org.fasterxml.jackson.databind.ObjectMapper的实例，并希望获得一个具有漂亮JSON的String。我在谷歌上搜索的所有结果都给出了Jackson 1.x的方法，而我似乎找不到合适的、非弃用的2.2方法来做到这一点。尽管我不认为代码对于这个问题是绝对必要的，但下面是我现在所拥有的：ObjectMapper mapper = new Object

问来自Jackson 2.2的ObjectMapper的漂亮打印JSON
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问来自Jackson 2.2的ObjectMapper的漂亮打印JSON
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