Java tutorial
/******************************************************************************* * Copyright (c) 2005, 2014 springside.github.io * * Licensed under the Apache License, Version 2.0 (the "License"); *******************************************************************************/ package org.springside.examples.showcase.demos.utilities.json; import static org.assertj.core.api.Assertions.*; import java.io.IOException; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Map.Entry; import javax.xml.bind.annotation.XmlElement; import javax.xml.bind.annotation.XmlTransient; import javax.xml.bind.annotation.XmlType; import org.joda.time.DateTime; import org.joda.time.format.DateTimeFormat; import org.junit.Test; import org.springside.modules.mapper.JsonMapper; import com.fasterxml.jackson.annotation.JsonAnyGetter; import com.fasterxml.jackson.annotation.JsonAnySetter; import com.fasterxml.jackson.annotation.JsonBackReference; import com.fasterxml.jackson.annotation.JsonFormat; import com.fasterxml.jackson.annotation.JsonIgnore; import com.fasterxml.jackson.annotation.JsonManagedReference; import com.fasterxml.jackson.annotation.JsonProperty; import com.fasterxml.jackson.annotation.JsonPropertyOrder; import com.fasterxml.jackson.annotation.JsonView; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.databind.DeserializationContext; import com.fasterxml.jackson.databind.JavaType; import com.fasterxml.jackson.databind.JsonMappingException; import com.fasterxml.jackson.databind.ObjectWriter; import com.fasterxml.jackson.databind.PropertyNamingStrategy; import com.fasterxml.jackson.databind.SerializerProvider; import com.fasterxml.jackson.databind.cfg.MapperConfig; import com.fasterxml.jackson.databind.deser.std.StdDeserializer; import com.fasterxml.jackson.databind.introspect.AnnotatedMethod; import com.fasterxml.jackson.databind.module.SimpleModule; import com.fasterxml.jackson.databind.ser.std.StdSerializer; import com.fasterxml.jackson.datatype.joda.JodaModule; import com.google.common.collect.Lists; import com.google.common.collect.Maps; /** * Jackson???Feature. * * @author calvin */ public class JsonDemo { private static JsonMapper mapper = JsonMapper.nonDefaultMapper(); // // ? //// /** * ?/?Json. */ @Test public void toJson() throws Exception { // Bean TestBean bean = new TestBean("A"); String beanString = mapper.toJson(bean); System.out.println("Bean:" + beanString); assertThat(beanString).isEqualTo("{\"name\":\"A\"}"); // Map Map<String, Object> map = Maps.newLinkedHashMap(); map.put("name", "A"); map.put("age", 2); String mapString = mapper.toJson(map); System.out.println("Map:" + mapString); assertThat(mapString).isEqualTo("{\"name\":\"A\",\"age\":2}"); // List<String> List<String> stringList = Lists.newArrayList("A", "B", "C"); String listString = mapper.toJson(stringList); System.out.println("String List:" + listString); assertThat(listString).isEqualTo("[\"A\",\"B\",\"C\"]"); // List<Bean> List<TestBean> beanList = Lists.newArrayList(new TestBean("A"), new TestBean("B")); String beanListString = mapper.toJson(beanList); System.out.println("Bean List:" + beanListString); assertThat(beanListString).isEqualTo("[{\"name\":\"A\"},{\"name\":\"B\"}]"); // Bean[] TestBean[] beanArray = new TestBean[] { new TestBean("A"), new TestBean("B") }; String beanArrayString = mapper.toJson(beanArray); System.out.println("Array List:" + beanArrayString); assertThat(beanArrayString).isEqualTo("[{\"name\":\"A\"},{\"name\":\"B\"}]"); } /** * Json???/?. */ @Test public void fromJson() throws Exception { // Bean String beanString = "{\"name\":\"A\"}"; TestBean bean = mapper.fromJson(beanString, TestBean.class); System.out.println("Bean:" + bean); // Map String mapString = "{\"name\":\"A\",\"age\":2}"; Map<String, Object> map = mapper.fromJson(mapString, HashMap.class); System.out.println("Map:"); for (Entry<String, Object> entry : map.entrySet()) { System.out.println(entry.getKey() + " " + entry.getValue()); } // List<String> String listString = "[\"A\",\"B\",\"C\"]"; List<String> stringList = mapper.fromJson(listString, List.class); System.out.println("String List:"); for (String element : stringList) { System.out.println(element); } // List<Bean> String beanListString = "[{\"name\":\"A\"},{\"name\":\"B\"}]"; JavaType beanListType = mapper.contructCollectionType(List.class, TestBean.class); List<TestBean> beanList = mapper.fromJson(beanListString, beanListType); System.out.println("Bean List:"); for (TestBean element : beanList) { System.out.println(element); } } /** * ???Inclusion. */ @Test public void threeTypeInclusion() { TestBean bean = new TestBean("A"); // ? JsonMapper normalMapper = new JsonMapper(); assertThat(normalMapper.toJson(bean)) .isEqualTo("{\"name\":\"A\",\"defaultValue\":\"hello\",\"nullValue\":null}"); // ??nullValue JsonMapper nonEmptyMapper = JsonMapper.nonEmptyMapper(); assertThat(nonEmptyMapper.toJson(bean)).isEqualTo("{\"name\":\"A\",\"defaultValue\":\"hello\"}"); // ???nullValuedefaultValue JsonMapper nonDefaultMaper = JsonMapper.nonDefaultMapper(); assertThat(nonDefaultMaper.toJson(bean)).isEqualTo("{\"name\":\"A\"}"); } /* * JaxbannotaionproperNameignorepropertyOrder */ @Test public void jacksonAnnoation() { TestBean2 testBean = new TestBean2(1, "foo", 18); // name???productNameageignore assertThat(mapper.toJson(testBean)).isEqualTo("{\"productName\":\"foo\",\"id\":1}"); } /* * Jaxbannotaion */ @Test public void jaxbAnnoation() { JsonMapper newMapper = new JsonMapper(); newMapper.enableJaxbAnnotation(); TestBean3 testBean = new TestBean3(1, "foo", 18); // name???productNameageignore assertThat(newMapper.toJson(testBean)).isEqualTo("{\"productName\":\"foo\",\"id\":1}"); } // ? @JsonPropertyOrder({ "name", "id" }) public static class TestBean2 { public long id; @JsonProperty("productName") public String name; @JsonIgnore public int age; public TestBean2() { } public TestBean2(long id, String name, int age) { this.id = id; this.name = name; this.age = age; } } // ? @XmlType(propOrder = { "name", "id" }) public static class TestBean3 { public long id; @XmlElement(name = "productName") public String name; @XmlTransient public int age; public TestBean3() { } public TestBean3(long id, String name, int age) { this.id = id; this.name = name; this.age = age; } } /** * BeanJSON??Bean?. */ @Test public void updateBean() { String jsonString = "{\"name\":\"A\"}"; TestBean bean = new TestBean(); bean.setDefaultValue("Foobar"); mapper.update(jsonString, bean); // name assertThat(bean.getName()).isEqualTo("A"); // DefaultValue?Json?? assertThat(bean.getDefaultValue()).isEqualTo("Foobar"); } /** * jsonp?. */ @Test public void jsonp() { TestBean bean = new TestBean("foo"); assertThat(mapper.toJsonP("callback", bean)).isEqualTo("callback({\"name\":\"foo\"})"); } /** * Bean, ???Mapper?Null???. */ public static class TestBean { private String name; private String defaultValue = "hello"; // ??? private String nullValue = null; // ???? public TestBean() { } public TestBean(String name) { this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getDefaultValue() { return defaultValue; } public void setDefaultValue(String defaultValue) { this.defaultValue = defaultValue; } public String getNullValue() { return nullValue; } public void setNullValue(String nullValue) { this.nullValue = nullValue; } @Override public String toString() { return "TestBean [defaultValue=" + defaultValue + ", name=" + name + ", nullValue=" + nullValue + "]"; } } // //?//// /** * ?. */ @Test public void enumType() { // toJSon?enum.name() assertThat(mapper.toJson(TestEnum.One)).isEqualTo("\"One\""); // fromJsonenum.name()enum.order() assertThat(mapper.fromJson("\"One\"", TestEnum.class)).isEqualTo(TestEnum.One); assertThat(mapper.fromJson("0", TestEnum.class)).isEqualTo(TestEnum.One); // enum.toString(), ???. // toString()indexenum.name()enum.order()????? JsonMapper newMapper = new JsonMapper(); newMapper.enableEnumUseToString(); assertThat(newMapper.toJson(TestEnum.One)).isEqualTo("\"1\""); assertThat(newMapper.fromJson("\"1\"", TestEnum.class)).isEqualTo(TestEnum.One); } /** * Bean. */ public static enum TestEnum { One(1), Two(2), Three(3); private final int index; TestEnum(int index) { this.index = index; } @Override public String toString() { return String.valueOf(index); } } /** * ?,Timestamp??2.0??@JsonFormat?. * JodaTime???Timestamp?, JodaTime.toString(). */ @Test public void dateType() { mapper.getMapper().registerModule(new JodaModule()); Date date = new Date(); DateTime dateTime = new DateTime(date); String timestampString = String.valueOf(date.getTime()); String format = "yyyy-MM-dd HH:mm:ss"; String formatedString = new DateTime(date).toString(format); DateBean dateBean = new DateBean(); dateBean.startDate = date; dateBean.endDate = date; dateBean.dateTime = dateTime; // to json String expectedJson = "{\"startDate\":" + timestampString + ",\"endDate\":\"" + formatedString + "\",\"dateTime\":" + timestampString + "}"; assertThat(mapper.toJson(dateBean)).isEqualTo(expectedJson); // from json Date expectedEndDate = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss").parseDateTime(formatedString) .toDate(); DateBean resultBean = mapper.fromJson(expectedJson, DateBean.class); assertThat(resultBean.startDate).isEqualTo(date); assertThat(resultBean.endDate).isEqualTo(expectedEndDate); } public static class DateBean { // timestamp public Date startDate; // annotation? @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+08:00") public Date endDate; public DateTime dateTime; } /** * ,,Empty?,"null". */ @Test public void nullAndEmpty() { // toJson // // Null Bean TestBean nullBean = null; String nullBeanString = mapper.toJson(nullBean); assertThat(nullBeanString).isEqualTo("null"); // Empty List List<String> emptyList = Lists.newArrayList(); String emptyListString = mapper.toJson(emptyList); assertThat(emptyListString).isEqualTo("[]"); // fromJson // // Null String for Bean TestBean nullBeanResult = mapper.fromJson(null, TestBean.class); assertThat(nullBeanResult).isNull(); nullBeanResult = mapper.fromJson("null", TestBean.class); assertThat(nullBeanResult).isNull(); // Null/Empty String for List List nullListResult = mapper.fromJson(null, List.class); assertThat(nullListResult).isNull(); nullListResult = mapper.fromJson("null", List.class); assertThat(nullListResult).isNull(); nullListResult = mapper.fromJson("[]", List.class); assertThat(nullListResult).isEmpty(); } // // //// /** * ?POJO. */ @Test public void cycleReferenceBean() { // ?parentchildren? child1,child2, child1/child2parent??parent. CycleReferenceBean parent = new CycleReferenceBean("parent"); CycleReferenceBean child1 = new CycleReferenceBean("child1"); child1.setParent(parent); parent.getChildren().add(child1); CycleReferenceBean child2 = new CycleReferenceBean("child2"); child2.setParent(parent); parent.getChildren().add(child2); // ?, jsonchildrenchild1/child2??parent String jsonString = "{\"name\":\"parent\",\"children\":[{\"name\":\"child1\"},{\"name\":\"child2\"}]}"; assertThat(mapper.toJson(parent)).isEqualTo(jsonString); // ???child1??parent? assertThat(mapper.toJson(child1)).isEqualTo("{\"name\":\"child1\"}"); // ????Json?parentchild1/child2. CycleReferenceBean parentResult = mapper.fromJson(jsonString, CycleReferenceBean.class); assertThat(parentResult.getChildren().get(0).getParent().getName()).isEqualTo("parent"); // ????child1parent CycleReferenceBean child1Result = mapper.fromJson("{\"name\":\"child1\"}", CycleReferenceBean.class); assertThat(child1Result.parent).isNull(); assertThat(child1Result.getName()).isEqualTo("child1"); } /** * ?POJOBean,@JsonBackReference @JsonManagedReference . */ public static class CycleReferenceBean { private String name; private CycleReferenceBean parent; private List<CycleReferenceBean> children = Lists.newArrayList(); public CycleReferenceBean() { } public CycleReferenceBean(String name) { this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } // ?gettersetter?annotation @JsonBackReference public CycleReferenceBean getParent() { return parent; } @JsonBackReference public void setParent(CycleReferenceBean parent) { this.parent = parent; } @JsonManagedReference public List<CycleReferenceBean> getChildren() { return children; } @JsonManagedReference public void setChildren(List<CycleReferenceBean> children) { this.children = children; } } /** * ?Bean. * ?Bean?Map<String,object> * ??? * Jackson???Map??@JsonAnyGetter/SetterMap? */ @Test public void extensibleBean() { // ??MapJSON. String jsonString = "{\"name\" : \"Foobar\",\"age\" : 37,\"occupation\" : \"coder man\"}"; ExtensibleBean extensibleBean = mapper.fromJson(jsonString, ExtensibleBean.class); // assertThat(extensibleBean.getName()).isEqualTo("Foobar"); assertThat(extensibleBean.getProperties().get("name")).isNull(); // ? assertThat(extensibleBean.getProperties().get("occupation")).isEqualTo("coder man"); } /** * ?Bean.@JsonAnySetter@JsonAnyGetter. */ public static class ExtensibleBean { // private String name; // private final Map<String, String> properties = Maps.newHashMap(); public ExtensibleBean() { } @JsonAnySetter public void add(String key, String value) { properties.put(key, value); } @JsonAnyGetter public Map<String, String> getProperties() { return properties; } public String getName() { return name; } public void setName(String name) { this.name = name; } } /** * ??POJO???????Jackson?View?. */ @Test public void multiViewBean() throws IOException { MultiViewBean multiViewBean = new MultiViewBean(); multiViewBean.setName("Foo"); multiViewBean.setAge(16); multiViewBean.setOtherValue("others"); // public view ObjectWriter publicWriter = mapper.getMapper().writerWithView(Views.Public.class); assertThat(publicWriter.writeValueAsString(multiViewBean)) .isEqualTo("{\"name\":\"Foo\",\"otherValue\":\"others\"}"); // internal view ObjectWriter internalWriter = mapper.getMapper().writerWithView(Views.Internal.class); assertThat(internalWriter.writeValueAsString(multiViewBean)) .isEqualTo("{\"age\":16,\"otherValue\":\"others\"}"); } public static class Views { static class Public { } static class Internal { } } /** * ???View??Bean. */ public static class MultiViewBean { private String name; private int age; private String otherValue; @JsonView(Views.Public.class) public String getName() { return name; } public void setName(String name) { this.name = name; } @JsonView(Views.Internal.class) public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getOtherValue() { return otherValue; } public void setOtherValue(String otherValue) { this.otherValue = otherValue; } } // ////// /** * ????MoneyLong. */ @Test public void customConverter() { JsonMapper newMapper = JsonMapper.nonEmptyMapper(); SimpleModule moneyModule = new SimpleModule("MoneyModule"); moneyModule.addSerializer(new MoneySerializer()); moneyModule.addDeserializer(Money.class, new MoneyDeserializer()); newMapper.getMapper().registerModule(moneyModule); // tojson User user = new User(); user.setName("foo"); user.setSalary(new Money(1.2)); String jsonString = newMapper.toJson(user); assertThat(jsonString).isEqualTo("{\"name\":\"foo\",\"salary\":\"1.2\"}"); // from User resultUser = newMapper.fromJson(jsonString, User.class); assertThat(resultUser.getSalary().value).isEqualTo(1.2); } public class MoneySerializer extends StdSerializer<Money> { public MoneySerializer() { super(Money.class); } @Override public void serialize(Money value, JsonGenerator jgen, SerializerProvider provider) throws IOException { jgen.writeString(value.toString()); } } public class MoneyDeserializer extends StdDeserializer<Money> { public MoneyDeserializer() { super(Money.class); } @Override public Money deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException { return Money.valueOf(jp.getText()); } } public static class Money { private final Double value; public Money(Double value) { this.value = value; } public static Money valueOf(String value) { Double srcValue = Double.valueOf(value); return new Money(srcValue); } @Override public String toString() { return value.toString(); } } /** * ?Money. */ public static class User { private String name; private Money salary; public String getName() { return name; } public void setName(String name) { this.name = name; } public Money getSalary() { return salary; } public void setSalary(Money salary) { this.salary = salary; } } /** * ?? */ @Test public void customPropertyNaming() throws JsonMappingException { TestBean bean = new TestBean("foo"); bean.setDefaultValue("bar"); JsonMapper newMapper = JsonMapper.nonEmptyMapper(); newMapper.getMapper().setPropertyNamingStrategy(new LowerCaseNaming()); assertThat(newMapper.toJson(bean)).isEqualTo("{\"name\":\"foo\",\"defaultvalue\":\"bar\"}"); } public static class LowerCaseNaming extends PropertyNamingStrategy { @Override public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName) { return defaultName.toLowerCase(); } } }