Gson解析Json示例源码

package com.gson.test; import java.util.ArrayList; import java.util.Date; import java.util.HashMap; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.Map.Entry; import org.junit.Test; import com.google.gson.FieldNamingPolicy; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.reflect.TypeToken; public class GsonTest { private static final Gson gson1 = new Gson(); private static final Gson gson2 = new GsonBuilder() // 美化输出结果 .setPrettyPrinting() // 设置日期格式 .setDateFormat("yyyy年MM月dd日-HH时mm分ss秒") // 为Student类注册StudentTypeAdapter,定制序列化和反序列化规则 .registerTypeAdapter(Student.class, new StudentTypeAdapter()) // 设置字段的命名规则，对使用@SerializedName注解的字段无效 .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE) // 设置排除策略 .setExclusionStrategies(new MyExclusionStrategy(Gender.class)) // 仅序列化和反序列化带有@Expose注解的字段 // 注解格式：@Expose (serialize = false, deserialize = false) // .excludeFieldsWithoutExposeAnnotation() // 序列化空值，默认空值不会序列化 // .serializeNulls() // 开启版本控制，与@Until、@Since注解配合使用 .setVersion(1.7) // 启用对Map中复杂对象的序列化支持 .enableComplexMapKeySerialization().create(); private static final Gson gson3 = new GsonBuilder() // 美化输出结果 .setPrettyPrinting() // 设置日期格式 .setDateFormat("yyyy年MM月dd日-HH时mm分ss秒").registerTypeAdapter(Gender.class, new GenderSerializer()) // 仅序列化和反序列化带有@Expose注解的字段 // 注解格式：@Expose (serialize = false, deserialize = false) .excludeFieldsWithoutExposeAnnotation().create(); @Test public void testGson1() { Student user1 = new Student(9527, "瓦力", 16); Student user2 = new Student(89757, "雪莉", 14); // 将对象转换为json字符串 String userStr = gson1.toJson(user1); System.out.println(userStr); List<Student> userList = new ArrayList<Student>(); userList.add(user1); userList.add(user2); // 将对象集合转换为json字符串 String listStr = gson1.toJson(userList); System.out.println(listStr); Teacher teacher = new Teacher(200802, "潮歌", userList); // 将对象转换为json字符串 String jsonStr = gson1.toJson(teacher); System.out.println(jsonStr); // 将json字符串还原为对象 Student user = gson1.fromJson(userStr, Student.class); System.out.println(user); // 将json字符串还原为对象集合 List<Student> users = gson1.fromJson(listStr, new TypeToken<List<Student>>() { }.getType()); System.out.println(users); } @Test public void testGson2() { Student user1 = new Student(9527, "瓦力", 16); Student user2 = new Student(89757, "雪莉", 14); user1.setEnrollmentDate(new Date()); user1.setGraduationDate(new Date()); // 将对象转换为json字符串 String userStr = gson2.toJson(user1); System.out.println(userStr); List<Student> userList = new ArrayList<Student>(); userList.add(user1); userList.add(user2); // 将对象集合转换为json字符串 String listStr = gson2.toJson(userList); System.out.println(listStr); // 为保证对象序列化时的顺序，此处使用LinkedHashMap Map<String, Student> map = new LinkedHashMap<String, Student>(); map.put(user1.getName(), user1); map.put(user2.getName(), user2); // 将对象Map转换为json字符串 String mapStr = gson2.toJson(map); System.out.println(mapStr); Map<String, Student> retMap = gson2.fromJson(mapStr, new TypeToken<Map<String, Student>>() { }.getType()); for (Entry<String, Student> entry : retMap.entrySet()) { System.out.println(entry.getKey() + ":" + entry.getValue()); } } @Test public void testGson3() { Student user1 = new Student(9527, "瓦力", 16); Student user2 = new Student(89757, "雪莉", 14); user1.setGender(Gender.MALE); user2.setGender(Gender.FEMALE); // 将对象转换为json字符串 String userStr = gson3.toJson(user1); System.out.println(userStr); List<Student> userList = new ArrayList<Student>(); userList.add(user1); userList.add(user2); // 将对象集合转换为json字符串 String listStr = gson3.toJson(userList); System.out.println(listStr); Map<String, Student> map = new HashMap<String, Student>(); map.put(user1.getName(), user1); map.put(user2.getName(), user2); // 将对象Map转换为json字符串 String mapStr = gson3.toJson(map); System.out.println(mapStr); Map<String, Student> retMap = gson3.fromJson(mapStr, new TypeToken<Map<String, Student>>() { }.getType()); for (Entry<String, Student> entry : retMap.entrySet()) { System.out.println(entry.getKey() + ":" + entry.getValue()); } } }