asmhatre
c438afc33b
37 runnable examples covering the eight feature posts on ankurm.com, verified against Jackson 3.2.1 on Temurin 21.0.5. Every output committed under docs/ was produced by run-all.sh. Also documents 11 places where the published snippets do not compile or do not behave as printed against a real Jackson 3 build - most notably that writeValueAsString(List<Base>) silently drops the polymorphic type discriminator, so the post's serialised output cannot be read back.
51 lines
2.2 KiB
Java
51 lines
2.2 KiB
Java
package com.ankurm.jackson3.part1objectmapper;
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import com.fasterxml.jackson.annotation.JsonPropertyOrder;
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import tools.jackson.databind.json.JsonMapper;
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/**
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* BEYOND THE POST — no blog section covers this, but it bites on first run.
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*
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* A record serialises in declaration order. A getter-based POJO serialises in
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* ALPHABETICAL order. If you are diffing Jackson output against a fixture, this
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* is usually the reason the diff is not empty.
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*/
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public class B04PropertyOrdering {
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/** Getter-based POJO: output is alphabetical, NOT declaration order. */
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public static class ProductPojo {
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private Long productId;
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private String productName;
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private double listPrice;
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public ProductPojo(Long i, String n, double p) { productId = i; productName = n; listPrice = p; }
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public Long getProductId() { return productId; }
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public String getProductName() { return productName; }
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public double getListPrice() { return listPrice; }
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}
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/** Record: output follows the component declaration order. */
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public record ProductRecord(Long productId, String productName, double listPrice) { }
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/** Explicit ordering wins over both defaults. */
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@JsonPropertyOrder({ "productId", "productName", "listPrice" })
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public static class ProductOrdered {
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private final Long productId;
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private final String productName;
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private final double listPrice;
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public ProductOrdered(Long i, String n, double p) { productId = i; productName = n; listPrice = p; }
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public Long getProductId() { return productId; }
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public String getProductName() { return productName; }
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public double getListPrice() { return listPrice; }
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}
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public static void main(String[] args) {
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JsonMapper mapper = JsonMapper.builder().build();
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System.out.println("POJO : " + mapper.writeValueAsString(
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new ProductPojo(1L, "Mechanical Keyboard", 79.99)));
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System.out.println("record : " + mapper.writeValueAsString(
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new ProductRecord(1L, "Mechanical Keyboard", 79.99)));
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System.out.println("ordered : " + mapper.writeValueAsString(
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new ProductOrdered(1L, "Mechanical Keyboard", 79.99)));
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}
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}
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