这是indexloc提供的服务，不要输入任何密码
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BAEL-7264 How to Pretty-print a Map in Java #15909

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merged 1 commit into from
Feb 23, 2024
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BAEL-7264 How to Pretty-print a Map in Java #15909

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14 changes: 11 additions & 3 deletions core-java-modules/core-java-collections-maps-7/pom.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -32,17 +32,22 @@
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>32.1.2-jre</version>
<version>${guava.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-core</artifactId>
<version>1.37</version>
<version>${jmh.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-generator-annprocess</artifactId>
<version>1.37</version>
<version>${jmh.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-collections4</artifactId>
<version>${commons-collections.version}</version>
</dependency>
</dependencies>

Expand All @@ -63,6 +68,9 @@
<properties>
<gson.version>2.10.1</gson.version>
<csv.version>1.5</csv.version>
<guava.version>32.1.2-jre</guava.version>
<jmh.version>1.37</jmh.version>
<commons-collections.version>4.4</commons-collections.version>
</properties>

</project>
202 changes: 202 additions & 0 deletions ...lections-maps-7/src/test/java/com/baeldung/map/prettyprintmap/PrettyPrintMapUnitTest.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,202 @@
package com.baeldung.map.prettyprintmap;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Joiner;
import com.google.gson.GsonBuilder;
import org.apache.commons.collections4.MapUtils;
import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.Test;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;

class PrettyPrintMapUnitTest {

private static final Map<String, Object> MAP;

static {
// using LinkedHashMap to keep insertion order, helpful in assertions
MAP = new LinkedHashMap<>();
MAP.put("one", 1);
MAP.put("two", 2);

Map<String, Integer> innerMap = new LinkedHashMap<>();
innerMap.put("ten", 10);
innerMap.put("eleven", 11);

MAP.put("inner", innerMap);
}

@Test
void givenMap_whenToString_thenOneLine() {
String result = MAP.toString();

String expected = "{one=1, two=2, inner={ten=10, eleven=11}}";
Assertions.assertThat(result).isEqualTo(expected);
}

@Test
void givenMap_whenSimpleForEachLoop_thenPrettyPrintWithoutNested() {
StringBuilder result = new StringBuilder();

for (Map.Entry<?, ?> entry : MAP.entrySet()) {
result.append(String.format("%-15s : %s%n", entry.getKey(), entry.getValue()));
}

String expected =
"one : 1\n" +
"two : 2\n" +
"inner : {ten=10, eleven=11}\n";
Assertions.assertThat(result.toString()).isEqualToIgnoringNewLines(expected);
}

@Test
void givenMap_whenRecursionForEachLoop_thenPrettyPrint() {
String result = printMap(0, MAP);

String expected =
"one : 1\n" +
"two : 2\n" +
"inner :\n" +
" ten : 10\n" +
" eleven : 11\n";
Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
}

@Test
void givenMap_whenStream_thenPrettyPrintWithoutNested() {
StringBuilder result = new StringBuilder();

MAP.forEach((k, v) -> result.append(String.format("%-15s : %s%n", k, v)));

String expected =
"one : 1\n" +
"two : 2\n" +
"inner : {ten=10, eleven=11}\n";
Assertions.assertThat(result.toString()).isEqualToIgnoringNewLines(expected);
}

@Test
void givenMap_whenExtendedStream_thenPrettyPrintWithoutNested() {
String result = MAP.entrySet().stream()
.map(entry -> String.format("%-15s : %s", entry.getKey(), entry.getValue()))
.collect(Collectors.joining("\n"));

String expected =
"one : 1\n" +
"two : 2\n" +
"inner : {ten=10, eleven=11}\n";
Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
}
@Test
void givenMap_whenJackson_thenPrettyPrint() throws JsonProcessingException {
String result = new ObjectMapper().writerWithDefaultPrettyPrinter().writeValueAsString(MAP);

String expected =
"{\n" +
" \"one\" : 1,\n" +
" \"two\" : 2,\n" +
" \"inner\" : {\n" +
" \"ten\" : 10,\n" +
" \"eleven\" : 11\n" +
" }\n" +
"}";
Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
}

@Test
void givenMap_whenGson_thenPrettyPrint() {
String result = new GsonBuilder().setPrettyPrinting().create().toJson(MAP);

String expected =
"{\n" +
" \"one\": 1,\n" +
" \"two\": 2,\n" +
" \"inner\": {\n" +
" \"ten\": 10,\n" +
" \"eleven\": 11\n" +
" }\n" +
"}";
Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
}

@Test
void givenMap_whenApacheCommonsCollectionsDebugPrint_thenPrettyPrintWithClassNames() throws IOException {
try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
PrintStream ps = new PrintStream(baos)) {

MapUtils.debugPrint(ps, "map", MAP);
String result = baos.toString();

String expected =
"map = \n" +
"{\n" +
" one = 1 java.lang.Integer\n" +
" two = 2 java.lang.Integer\n" +
" inner = \n" +
" {\n" +
" ten = 10 java.lang.Integer\n" +
" eleven = 11 java.lang.Integer\n" +
" } java.util.LinkedHashMap\n" +
"} java.util.LinkedHashMap\n";
Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
}
}

@Test
void givenMap_whenApacheCommonsCollectionsVerbosePrint_thenPrettyPrint() throws IOException {
try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
PrintStream ps = new PrintStream(baos)) {

MapUtils.verbosePrint(ps, "map", MAP);
String result = baos.toString();

String expected =
"map = \n" +
"{\n" +
" one = 1\n" +
" two = 2\n" +
" inner = \n" +
" {\n" +
" ten = 10\n" +
" eleven = 11\n" +
" }\n" +
"}\n";
Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
}
}

@Test
void givenMap_whenGuavaJoiner_thenPrettyPrintWithoutNested() {
String result = Joiner.on(",\n").withKeyValueSeparator("=").join(MAP);

String expected =
"one=1,\n" +
"two=2,\n" +
"inner={ten=10, eleven=11}";
Assertions.assertThat(result).isEqualToIgnoringNewLines(expected);
}

private static String printMap(int leftPadding, Map<?, ?> map) {
StringBuilder ret = new StringBuilder();

for (Map.Entry<?, ?> entry : map.entrySet()) {
if (entry.getValue() instanceof Map) {
ret.append(String.format("%-15s :%n", entry.getKey()));
ret.append(printMap(leftPadding + 4, (Map<?, ?>) entry.getValue()));
}
else {
ret.append(String.format("%" + (leftPadding > 0 ? leftPadding : "") + "s" // adding padding
+ "%-15s : %s%n",
"", entry.getKey(), entry.getValue()));
}
}
return ret.toString();
}

}